Title of Invention	OXAZOLIDINONE DERIVATIVES, PROCESS FOR THEIR PREPARATION AND THEIR USE AS ANTIMYCOBACTERIAL AGENTS
Abstract	A compound of formula (I) and its pharmaceutical^ acceptable salts wherein, A is either hydrogen or fluorine, B is either hydrogen or fluorine, A and B together is hydrogen and fluorine, Ri is a group of formula, wherein, Q is either an alkyl group of two carbon atoms, an alkene group of two carbon atoms or an alkyne group of two carbon atoms Y is oxygen, sulfur or an amino function of formula NR3 wherein, R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or branched; cycloalkyl of 3-7 carbon atoms; CHO, -COOH, -COOR,; COCR,; CN; aryl or heteroaryl wherein, Rt is an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms. Ar is a substituted phenyl ring or a substituted pyridine ring of formula —O-R3 or Ar is a five membered ring of formula 48 or Ar is a fused bicyclic phenyl or pyridine ring of formula wherein, M is either CH or N Z is CH, NH, O, or S, X is a group selected from OR,, NR4R5, N02, SR,, SOOR,, SOONR4R5, F, CI, Br or I, wherein R4 is as defined hereinbefore, and and R3 is as defined hereinbefore R5 is hydrogen or R4 R2 is selected from the groups shown below, and the corresponding N-oxides thereof.

Title of Invention

OXAZOLIDINONE DERIVATIVES, PROCESS FOR THEIR PREPARATION AND THEIR USE AS ANTIMYCOBACTERIAL AGENTS

Abstract

A compound of formula (I) and its pharmaceutical^ acceptable salts wherein, A is either hydrogen or fluorine, B is either hydrogen or fluorine, A and B together is hydrogen and fluorine, Ri is a group of formula, wherein, Q is either an alkyl group of two carbon atoms, an alkene group of two carbon atoms or an alkyne group of two carbon atoms Y is oxygen, sulfur or an amino function of formula NR3 wherein, R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or branched; cycloalkyl of 3-7 carbon atoms; CHO, -COOH, -COOR,; COCR,; CN; aryl or heteroaryl wherein, Rt is an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms. Ar is a substituted phenyl ring or a substituted pyridine ring of formula —O-R3 or Ar is a five membered ring of formula 48 or Ar is a fused bicyclic phenyl or pyridine ring of formula wherein, M is either CH or N Z is CH, NH, O, or S, X is a group selected from OR,, NR4R5, N02, SR,, SOOR,, SOONR4R5, F, CI, Br or I, wherein R4 is as defined hereinbefore, and and R3 is as defined hereinbefore R5 is hydrogen or R4 R2 is selected from the groups shown below, and the corresponding N-oxides thereof.

Full Text	F0RM 2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See section 10; rule 13) 1. Title of the invention. - OXAZOLIDINONE DERIVATIVES, PROCESS FOR THEIR PREPARATION AND THEIR USE AS ANTIMYCOBACTERIAL AGENTS 2. Applicants) (a) NAME : LUPIN LIMITED (b) NATIONALITY : An Indian Company (c) ADDRESS : 159, C.S.T. Road, Kalina, Santacruz (East), Mumbai - 400 098, Maharashtra, India 3. PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed FIELD OF THE INVENTION The present invention relates to novel compounds belonging to the class of oxazolidinones useful in the treatment of acid fast organisms such as Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium spp. The present invention further relates to methods for preparation of the novel compounds and to pharmaceutical compositions containing the novel compounds useful in the treatment of tuberculosis. BACKGROUND OF THE INVENTION Tuberculosis (TB), an infectious disease caused by the bacterium Mycobacterium tuberculosis is transmitted mainly through air, affecting most often the lungs. When persons with pulmonary TB cough they produce tiny droplet nuclei containing M. tuberculosis, which remain suspended in air for a prolonged period of time. A person who breathes the air containing the aforesaid droplet nuclei containing M. tuberculosis can become infected with TB. TB, one of the three major infectious diseases in the priority list of the World Health Organization's (WHO) agenda kills about two million people around the world every year. About six million new cases are reported every year and nearly 20% of adult deaths and 6% of infant deaths are attributable to the disease (C. Dye et. al., J. Am. Med. Ass., 1999, 282, 677-686). About a billion people are expected to be affected by TB by the year 2020, with 35 million likely to succumb to the disease (WHO Fact Sheet No. 104, Global Alliance for TB Drug Development- Executive Summary of the Scientific Blueprint for TB Development : http://www.who.int/inf-fs/en/factl04.html). With the emergence of the AIDS epidemic and the increase in cases of HIV coupled with TB as well as the continued resistance of M. tuberculosis to isoniazid and rifampicin, the two most powerful anti-tubercular drugs available today there is an urgent need for new anti-tubercular drugs to combat the killer disease (S. H. E. Kaufmann et. al., Trends Microbiol., 1993, 1,2-5 ; B. R. Bloom et. al., N. Engl. J. Med., 1998, 338, 677-678). Although, many new compounds are becoming available for fighting a number of infectious diseases, the number of such compounds having antimycobacterial activity are few. This could partly be due to the complexity of research involved and partly due to business considerations (B. N. Roy et. al., J. Ind. Chem. Soc, April 2002, 79, 320-335 and references cited therein). However, renewed thrust in research in the last decade has resulted in development of new antimycobacterial compounds, a) differing widely in structures, b) having different mode/mechanism of action, c) possessing favourable pharmacokinetic properties, d) which are safe and have low incidence of side-effects, and e) which provide a cost-effective dosage regimen. 2 Among the aforesaid new compounds, the oxazolidinones first developed during the mid-1980s (W. A. Gregory et. al., J. Med. Chem., 1989, 32,1673-1681 and 1990,33,2569-2578 ; C-H Park et. al., J. Med. Chem., 1992, 35, 1156-1165) are a unique class in themselves. The in vivo results for some of the oxazolidinones show that they are active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, including resistant strains such as methicillin-resistant Staphylococcus aureus [MRSA], methicillin-resistant Streptococcus epidermidis [MRSE], penicillin-resistant Streptococcus pneumoniae [PRSP], vancomycin-resistant enterococci [VRE], etc. (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999,9 (5), 625-633 and the references contained therein). The oxazolidinones inhibit bacterial protein synthesis at a very early step in the initiation of complex formation involved in the process of translating mRNA into protein. The oxazolidinones, in general, are not cross-resistant with any known antibiotic because of this unique mechanism (D. C. Eustice et. al., Antimicrob. Agents Chemother., 1988, 32, 1218 and Biochem. Biophys. Res. Commun., 1988,150. 965). A feature of the oxazolidinone molecule is that only those compounds, which are enantiomers with a (5S)-acetamidomethyl configuration in the left side of the molecule are known to exhibit antibacterial activity (W. A. Gregory et. al., J. Med. Chem., 1989, 32, 1673-1681). Another feature is that most of such antibacterial compounds invariably carry a (substituted) phenyl ring attached to the nitrogen atom of the oxazolidinone ring in the right side of the molecule (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999, 9 (5), 625-633 and the references contained therein). The most promising compound among the N-phenyl oxazolidinones, which has been approved for human use is (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidin-yl]methyl]-acetamide), commonly known as linezolid (M. Barbachyn et. al., WO 995/07271). Linezolid possesses good in vitro and in vivo potency against most of the Gram-positive bacteria, including resistant strains {Drugs of the Future, 1996,21.(11), 1116-1123). The left hand side i. e. position 5- and the right hand side i. e. position 3- respectively of the oxazolidinone ring nucleus allows for many variations and has resulted in the discovery of a large number of compounds having antimicrobial and antibacterial properties. Such representative compounds, albeit not meant to be limiting are disclosed in the following prior art references. These are: i) US 4,942,183 (Gregory et. al.) and US 4,948,801 (Carlson et. al.) collectively disclose certain 3-substituted phenyl- 5-aminomethyl oxazolidinones, possessing useful antibacterial activity, ii) US 5,529,998 (Habich et. al.) discloses certain 3-benzoxazoyl- and benzothiazolyl-5- acetyl amino methyl oxazolidinones, useful as antibacterial medicaments. 3 iii) US 5,565,571, US 5,654,428, US 5,756,732, US 5,801,246 and US 5,929,248 (Barbachyn et. al.) collectively disclose several substituted aryl and heteroaryl phenyloxazolidinones carrying an acetyl aminomethyl function at the 5-position, specifically oxazolidinones having an aryl or heteroaryl group at the para position of the 3-phenyl ring and additional substituents at the meta positions of the 3-phenyl ring, which are useful as antibacterials. iv) US 5,652,238 (Brickner et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a hydroxyl acetyl piperazine moiety, active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, as well as anerobic organisms such as bacteroides and Clostridia species as well as acid-fast organisms such as Mycobacterium tuberculosis. v) US 5,684,023 (Riedl et. al.) discloses certain 3- benzofuranyl- and benzothienyl oxazolidinones, carrying an azido, hydroxy or acetyl aminomethyl group at the 5-position, useful as antibacterial medicaments. vi) US 5,688,792 (Barbachyn et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a (substituted)-morpholine. Such compounds are useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp. vii) US 5,719,154 (Tucker et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the said substitution being a pyrimidinyl or pyradazinyl group. Such compounds are useful as antimicrobial agents. viii) US 5,736,545 (Gadwood et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a five membered heterocycle ring, in particular an azolyl ring. Such compounds are useful in the treatment of microbial infections. ix) US 5,792,765 (Riedl. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-substituted phenyloxazolidinones, the substitution being a heterocyclic moiety, useful as antibacterial medicaments. x) US 5,861,413 (Habich et. al.) discloses certain 2-oxo and 2-thio-l,2-dihydroxyqoinolinyl-1-oxazolidinones, useful as antibacterial medicaments. xi) US 5,880,118 (Barbachyn et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a 4 substituted thiomorholine moiety i. e. oxazine and thiazine derivatives, useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp. xii) US 5,910,504 and US 6,124,334 (Hutchinson et. al.) collectively disclose certain substituted 5-acetyl aminomethyl-3- phenyloxazolidinones substituted at the para position of the 3-phenyl ring with a heteroaromatic moiety, which is five membered having one to four nitrogen atoms or alternatively, a benzoannulated five-membered heteroaromatic ring having one to four nitrogen atoms, useful as antibacterials. xiii) US 6,069,160 (Stolle et. al.) discloses certain substituted 5-acetyl aminomethyl-3-benzocyclopentaneoxazolidinones, containing an heteroatom, useful as antibacterial medicaments. xiv) US 6,227,868 Bl and US 6,410,728 (Sciotti et. al.) collectively disclose certain 5-acetyl aminomethyl-3-phenyloxazolidinones carrying an acetylenic moiety on the 3-phenyl ring, useful for treating bacterial infections, psoriasis, arthritis and toxicity due to chemotherapy. xv) WO 93/23384 (Hutchinson et. al.) discloses certain substituted 5-acetyl aminomethyl-3 -phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, useful for treatment of microbial infections caused by staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium. xvi) WO 97/10223 (Gadwood et. al.) discloses certain substituted 5-acetyl aminomethyl-3-aminoaryl oxazolidinone N-oxide compounds, which are exceedingly water soluble and useful in preparation of pharmaceutical compositions for combating a number of human and veterinary pathogens, staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium, Mycobacterium spp. and Mycoplasma spp. xvii) WO 98/01446 and WO 98/01447 (Betts et. al.) collectively disclose certain substituted 5-acetyl aminomethyl3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a six-membered heteroaryl ring containing two or three ring nitrogen atoms as the only ring heteroatoms, useful as antibacterial agents. xviii) WO 99/02525 (Thomasco et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted by a thiadiazolyl or oxadiazolyl moiety, useful as 5 antimicrobial agents, effective against a number of human and veterinary pathogens, including Gram-positive and Gram-negative aerobic bacteria. xix) WO 99/37630 (Gordeev et. al.) discloses oxazolidinone combinatorial libraries, compositionscontaining the same and methods of preparation thereof involving solid phase synthesis, which provides the said compounds for high-throughput screening. xx) W099/37641 (Bartel. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-bicyclene-substituted oxazolidinones, useful as antibacterial medicaments. xxi) WO 01/09107 (Gordeev et. al.) discloses certain 3-heteroaryl-5-acetyl aminomethyl oxazolidinones, substituted by a thioacyl, aminocarbonyl, alkoxycarbonyl, aminothiocarbonyl, alkoxythiocarbonyl and alkylthiocarbonyl group, useful in treating or preventing an infectious disorder in humans or animals. xxii) WO 01/42242 (Paget et. al.) discloses certain substituted 5-acetyl aminomethyl 3-substituted phenyloxazolidinones, the substitution being a bicyclic heterocyclic system, useful as antibacterial agents. xxiii) WO 02/06278 (Mehta et. al) discloses certain substituted 3-phenyl oxazolidinones and to process for synthesis of the same, the said compounds useful as antibacterial agents, effective against a large number of human and veterinary pathogens, including Gram-positive bacteria and acid fast organisms such as Mycobacterium tuberculosis. xxiv) WO 02/20515 (Madar et. al.) discloses heterocyclic phenyloxazolidinones, useful for treating bacterial infections. However, only a few of the disclosures described hereinbefore provide compounds that can be used as antimycobacterials, while most of the others are silent about the antimycobacterial activity of the disclosed compounds. A need, therefore, exists for new compounds possessing potent antimycobacterial properties for treatment of TB, which as mentioned hereinearlier is assuming alarming proportions. OBJECTS OF THE INVENTION It is thus the basic object of the present invention to synthesize, identify and provide new compounds belonging to the class of oxazolidinones, possessing potent antimycobacterial properties especially for treatment of acid fast organisms such as Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M. kansai. Another object is directed to providing antimycobacterial pharmaceutical composition effective in inhibiting/treating the generation of mycobacterial conditions/cells including Mycotacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M fortuitum and Mkansai. 6 Yet another object is directed to providing a method of treating/inhibiting mycobacterial cells/conditions involving the administrations of effective amount of the novel antimycobacterial compound and/or its salts /composition of the invention. SUMMARY OF THE INVENTION Thus according to the basic aspect of the present invention there is provided compound of formula (I) and its pharmaceutically acceptable salts thereof wherein, A, B = H, and/or F Ri is a group of formula wherein, Q is CH2-CH2, CH=CH, or C=C Y is O,S or NR3 wherein, R3 is Ci - C4 alkyl (straight, branched, unsaturated), cycloalkyl, COOH, COOR,, CHO, COCR4, CN, aryl, heteroaryl wherein, R is an alkane of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms, and Ar is an aromatic carbocycle represented by 7 wherein, X is OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, Br, CI, F, or I, M is-CHorN,and Zis-CH,-NH,OorS and wherein, R3 and R4 are as described hereinbefore, and R5 is H, or same as R4, and R.2 is selected from the groups shown below, and the corressponding N-oxides thereof Heteroaryl or Heterocycloalkyl wherein K is O, S, SO, S02, or CH2 According to another aspect of the invention there is provided a pharmaceutical composition comprising: i) atleast one of an antimycobacterially effective amounts of compound of formula I and pharmaceutically acceptable salts there of; and ii) a pharmaceutically acceptable carrier. According to yet another aspect of the present invention there is provided a method of inhibiting growth of mycobacterial cells such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M.kansai.,comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof. 8 According to yet another aspect of the present invention there is provided a method of treating mycobacterial conditions such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M kansai, comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof. According to another aspect, there is provided a process for the manufacture of the compound of formula I or its pharmaceutically acceptable salts comprising : coupling the amino fragments of compound of formula II with the carboxylic acid fragment of formula III. The above disclosed compound of formula I its pharmaceutically acceptable salts thereof are found to have antimycobacterial properties and the same in admixture with pharmaceutically active additives, an be administrated orally or paranterally for treatement of mycobacterial conditions especially TB. DETAILED DESCRIPTION OF THE INVENTION In the pharmaceutically active compound of formula (I) of this invention, the definition of the symbols and groups A, B, Rt and R2 are as follows : A is either hydrogen or fluorine, B is either hydrogen or fluorine, A and B together is hydrogen and fluorine, When A is hydrogen, B is fluorine and vice-versa. R1 represents a group of formula, Q is either an alkyl group of two carbon atoms (CH2-CH2), an alkene group of two to carbon atoms (CH=CH), or an alkyne group of two carbon atoms (C=C) 9 Y can either be oxygen, sulfur or an amino function of formula NR3, wherein R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or branched. Suitable alkyl groups are methyl, ethyl, n-propyl, n-butyl, iso-propyl, iso-butyl, tert- butyl, ethylene, propylene, 1, butene, both the geometric isomers of 2-butene i. e.(cis)-2-butene and (trans)-2-butene, and iso-butylene. or R3 is a cycloalkyl group of 3-7 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl, or R3 is a carboxylic acid group (-COOH) or a carboxylic acid ester of formula-COOR4, wherein R4 is H, an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms. R3 is further an aldehyde (-CHO), an acetyl group (-COCR4), wherein R4 is as mentioned hereinbefore or R3 is a nitrile (CN), aryl or heteroaryl, wherein Aryl is phenyl substituted with (0) or (1) of-F, -CI, -OCH3, -OH, -NH2, -CrC4 alkyl, -O-C(O)- OCH3,-N02or-CN,and Heteroaryl or Ar is a five membered ring of formula or Ar is a fused bicyclic phenyl or pyridine ring of formula 10 The group Ar is a substituted phenyl ring or a substituted pyridine ring of formula wherein, M is either CH or N; Z is -CH, -NH, O or S and R3 is as defined hereinbefore, X is a group selected from OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, F, CI, Br or I, wherein R4 is as defined hereinbefore, and R5 is hydrogen or R4. R2 is selected from the groups shown below, and the corresponding N-oxides thereof. Heteroaryl or Heterocycloalkyl wherein K is O, S, SO, S02, or CH2 The preferred novel compounds of formula (I) that form part of this invention, are as follows. The following compounds 1 to 78( named as per IUPAC or CAS nomenclature) are preferred compounds of formula (I) of the invention. 1. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide. 2. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 3. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 4. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide. 5. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 11 6. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide. 7. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide. 8. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 9. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 10. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 11. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methylphenyl) - 4- oxobutanamide. 12. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - (4 - methylphenyl) - 4- oxobutanamide. 13. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 14. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide. 15. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide. 16. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide. 17. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 18. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 19. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide. 20. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - (2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 21. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide. 22. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 23. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 12 24. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazohdinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 25. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazohdinyl methyl] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 26. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazohdinyl ] methyl - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide. 27. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 28. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl - 4 - oxo - 4 -( 2 - thienyl)butanamide. 29. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide. 30. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide. 31. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide. 32. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide. 33. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N - oxide. 34. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 35. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methoxyphenyl) - 4- oxobutanamide. 36. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - chlorophenyl) - 4- oxobutanamide. 37. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2,4 - dimethylphenyl) - 4- oxobutanamide. 38. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benztriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 39. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 40. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 41. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 13 42. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 43. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide. 44. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide. 45. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 46. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 47. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide. 48. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide. 49. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 50. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 51. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 52. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 -( 2 - thienyl)butanamide. 53. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 54. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 55. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - phenylbut - 2- enamide. 56. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo- 4 - ( 4 - thiomethylphenyl )butanamide. 57. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2 - naphthyl) - 4 - oxobutanamide. 58. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide. 59. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 14 60. (S) - N -[ [ 3 - (3 - fluoro—4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 61. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbut - 2- enamide. 62. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 63. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide. 64. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide. 65. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 66. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - (4 - thiomethylphenyl)butanamide. 67. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - ( 2 - naphthyl) - 4 - oxobutanamide. 68. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 69. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide. 70. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 71. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 72. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 73. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 74. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 75. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 76. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 77. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 15 78. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 — oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide. The respective N-oxides of the group R2 of the compounds of formula I listed above also form a novel aspect of the present invention. The pharmaceutically active compounds of formula (I), the corresponding N-oxides of the group R2 and pharmaceutically acceptable salts thereof of this invention can be prepared by methods known to one skilled in the art. Typically, compounds of formula (I), can be prepared by coupling of the amino fragment of formula (II) Scheme-! General method for synthesis of compounds of formula (I) In a typical experiment, the amine compound of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinbefore is dissolved in a 1:1 mixture of tertahydrofuran and water or a 1:1 mixture of methylene chloride and water. To the solution is added the carboxylic acid compound of formula (III), followed by addition of 1-hydroxybenztriazole (HOBt). The resulting mixture is cooled to a temperature of 0-5° C to which l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 1.1 Eq.) is added and gradually allowed to warm to room temperature and agitated at this temperature for 24 hours. At the end of 17 the reaction, a solution of saturated aqueous sodium bicarbonate is added and the organic phase separated from the aqueous phase. Evaporation of the solvent and chromatography of the residue over silica gel affords compound of formula (I), generally as white solids. The N-oxides of the group R2 of compound of formula (I) thus obtained are preferably prepared by addition of m-chloro perbenzoic acid (m-CPBA) to a cooled solution of the compound of formula (I) in a chlorinated hydrocarbon solvent such as methylene chloride and ethylene chloride and thereafter agitating the reaction mixture at room temperature for 12-15 hours. Evaporation of the solvent under reduced pressure, followed by chromatography of the residue over silica gel affords the corresponding N-oxides in high purity. The N-oxides thus prepared, while retaining most of the antimycobacterial activity of the corresponding deoxo compound exhibit exceedingly high water solubility over the deoxo analogue, thereby helping in manufacture of suitable iv formulations, which forms an important aspect of this invention. The starting materials required for synthesis of compound of formula (I), thus involve the amine compound of formula II and the carboxylic acid compound of formula III. The amine compound of formula II can be selected from i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vi) (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, and viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine. 18 The carboxylic acid compound of formula III can be selected from 4-(2-Naphthyl)-4- oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic acid, 4-oxo-4-(2'methylpropyl)phenylbutanoic acid, 4-Oxo-4- (2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 - oxobutanoic acid,4 - (2,4 - dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 - phenyl - but - 2 - ynoic acid. 20 Thus, the starting amines of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinearlier are prepared as per the method disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33, 2569-2578; C. Wang et. al., Tetrahedron, 1989, 45, 1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO 95/25106 and WO 97,21708. The method is essentially summarized in Scheme-II. In a typical method, morpholine, thiomorpholine, piperidine, 4-benzyl piperazine, pyrrolidine, 1,2,4-triazine, 12,3-benzotriazine, benzyl amine, a heterocycloalkyl or a heteroaryl moiety etc., each one of which corresponds to the group R2 defined hereinbefore is reacted with 3,4-difluoro nitrobenzene in the presence of a base and a solvent to give the corresponding derivative in which the fluorine atom at 4-position is substituted by the group R2. The nitro group in the compound thus obtained is reduced to amino group, which is thereafter protected by a suitable protective group. Reaction of the N-protected compound thus obtained with (R)-glycidyl butyrate in the presence of a strong base like n-butyl lithium leads to formation of the 5-hydroxymethyl oxazolidinone ring. The hydroxy group in the compound thus obtained is converted to sulfonyl derivative, for e.g. a methanesulfonyloxy (mesyl) or a p-toluenesulfonyloxy (tosyl) derivative by reaction with methanesulfonyl chloride or p-toluenesulfonyl chloride respectively. Reaction of the respective mesyl or tosyl derivative with sodium azide gives the corresponding azide, which is converted to the amine compound of formula (II) by standard methods, for e.g. by reaction with a triaryl/trialkyl phosphine, followed by hydrolysis. The starting carboxylic acid fragments of formula (III), wherein the group Ar has the same meaning as defined hereinearlier are prepared as per the method disclosed in Org. Reactions, 1949, 5, 229-289; Quart. Rev. Chem. Soc, 1954, 8, 355-379; Chem. Rev., 1955, 55, 229-281, and J. Am. Chem. Soc, 1947, 69, 1784-1786. The method is essentially summarized in Scheme-HI. Scheme-Ill General method for synthesis ofalkane and alkene carboxylic acid s of formula (HI) In a typical method, the aromatic compound Ar-H, wherein Ar is as defined hereinbefore is reacted with succinic anhydride in the presence of a Lewis acid, such as anhydrous aluminium chloride and in the presence of an anhydrous solvent and the mixture heated to 100° C to give the carboxylic acid derivatives of formula (HI), wherein Q is alkyl of 1-4 carbon atoms. 23 Similarly, compounds of formula (III), wherein Q is an alkene (CH=CH) are prepared by reaction of the aromatic compound Ar-H, wherein Ar is as defined hereinbefore with maleic anhydride under the same conditions mentioned hereinbefore. Compounds of formula (III), wherein Q is an alkyne (C=C) are prepared by reaction of propiolic acid ester with an aldehyde of formula Ar-CHO in the presence of butyl lithium and in the presence of an aprotic solvent such as THF at -78° C to give the corresponding secondary alcohol, which is oxidized to the keto derivative using manganese dioxide as the oxidizing agent. Saponification gives the carboxylic acid derivative of formula (ID) [ US 4,929,741 (A. Fischili et. al.) ] The synthesis is summarized in Scheme-IV. P = any protective group The synthesis of compound of formula (I) of this invention and the synthesis of the respective starting material amines of formula (II) and the carboxylic acids of formula (III) are further described herein in detail. SYNTHESIS OF THE STARTING AMINES OF FORMULA OD The amines were prepared as per the chemistry summarized in the Scheme-H and as per the methods disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33,2569-2578; C. Wang et. al., Tetrahedron, 1989, 45,1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO 24 95/25106 and WO 97,21708. Commercially available raw materials and known techniques were utilized for the synthesis. The optically pure amines as such were obtained by using optically active intermediates or resolution of racemic mixtures by a suitable reagent. The preferred enantiomer is (S), at the chiral centre on the oxazolidinone ring. Example 1 General Method for Preparation of the Amines (II) The oxazolidinone azides of general formula (8), given in Scheme-II (1.0 eq) were dissolved in dry THF (10 times by volume ) and treated with triphenyl phosphine (1.5 eq.) at room temp. The resulting solution was stirred for 6hrs at room temp. Water [2 eq. of (8)] was added and the solution heated for 6hrs at 55 - 60° C. The solvent was evaporated and the residue chromatographed on a column of silica gel (100 -200 mesh) and eluted initially with ethyl acetate and then with chloroform : methanol (4:1) to give the the amines (II) as white solids. The following amines i) to viii) of formula I were prepared by this general method, viz. i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vi) (S) - N -[3 - (3 - fluoro — 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, and viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine. SYNTHESIS OF THE STARTING CARBOXYLIC ACIDS OF FORMULA (HP Example 2 4-(2-Naphthyl)-4-oxobutanoic acid Naphthalene (5.0gm, 0.039moles) and succinic anhydride (4.68gm, 0.0468 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (11.44g, 0.0858 moles) was added at 25 room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 25 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid. Subsequent column chromatography gave a buff coloured solid. Subsequent chromatography gave 3.7 gm (41%) the title compound, mp 173-174° C. 'H NMR (CDCI3, 5) : 8.40 (s,lH), 7.7 - 8.0 ( m, 4H), 7.4 - 7.6 (m,2H), 3.33 (t,2H), 2.77 (t,2H + 1H). The filterate was concentrated to give 5.8 gm of a mixture of 4-(2-naphthyl)-4-oxobutanoic and 4-(l-naphthyl)-4-oxobutanoic acid. Example 3 4- Oxo-4-(2- ThienylJbutanoicacid Thiophene (5.0gm, 0.059moles) and succinic anhydride (7.13gm, 0.0713 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (17.43gm, 0.131 moles) was added at room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 30 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (50 ml). The solid was dried at room temp to give 9.8 gm (89%0 of the title compound, mp 103 - 107° C. !H NMR (CDCI3, 8) : 7.69 (dd, 1H), 7.58 (dd, 1H), 7.07 (dd,lH), 3.9 (bs, 1H), 3.23 (t, 2H), 2.74 (t,2H). Example 4 4- Oxo-4-(4-thiomethyl)phenylbutanoic acid Thiophenol methyl ether (8.0gm, 0.0645moles) and succinic anhydride (7.75gm, 0.0774 moles) were taken up in dichloroethane (80 ml). Aluminium chloride (18.90gm, 0.1419 moles) was added at room temperature. The resulting mixture stirred for 0.5hr and then heated at 85° C for lhr. The reaction mixture was cooled to room temperature, diluted with 40 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (80 ml). The solid was dried at room temp to give 6.9 gm (48%) of the title compound, mp 151 -154° C. H NMR (CDCI3, 5) : 7.82 (d,2H), 7.20 (d, 2H), 4.2 (bs, 1H), 3.21 (t, 2H), 2.73(t, 2H),2.45 (s,3H). 26 Example 5 4 - oxo -4- (2'methylpropyl)phenylbutanoic acid 2'methylpropylbenzene (5.0m, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles), were taken up in dichloroethane (50 ml). Aluminium chloride (10.90g, 0.0821 moles ) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 ml of a 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.7 gm (99%) of the title compound as a solid, mp 102 - 105° C. !H - NMR (CDC13, 8) : 7.83 (d,2H), 7.17(d,2H), 3.24(t,2H), 2.74(t, 2H), 2.46 (d, 2H), 1.80 (pent., 1H). Example 6 4 - Oxo - 4 - (2',2'dimethylethyl)phenylbutanoic acid 2',2'dimethylethylbenzene (5.0gm, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (10.90gm, 0.0821 moles) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 m of a 1:1 mixture of water Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.5 gm (97%) of the title compound as a solid, mp 103 — 107° C. !H-NMR (CDCI3,8) : 7.94(d,2H), 7.50 (d, 2H), 3.29 (t,2H), 2.82 (t,2H), 1.36 (s,9H). Example 7 Using the appropriate aromatic compound (Ar-H) and succinic anhydride and following exactly the method described in Examples 2-6 the following carboxylic acids can be prepared, viz. i) 4 -(4 -methylphenyl)- 4 - oxobutanoic acid, ii) 4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid, iii) 4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid, iv) 4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, v) 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, vi) 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid, vii) 4 -{2- Naphthyl)- 4 - oxobutanoic acid, viii) 4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, ix) (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and x) 4 - oxo - 4 - phenyl - but - 2 - ynoic acid. 27 SYNTHESIS OF THE COMPOUNDS OF FORMULA (D Example 7 Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - J - oxazolidinyl ] methyl] — 4-(4- naphthyl) -4- oxobutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 dichloromethane-water mixture (10 ml). To this was added 4 -( 2 - naphthyl- 4 - oxobutanoic acid (0.154gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) the resulting mixture was cooled to 0° C. l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added the resulting mixture was allowed to warm to room temperature and then stirred for 24hr. Saturated aqueous sodium bicarbonate solution (2ml) was added to the reaction mixture, stirred for 15 min and then the organic layer separated and the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.22 gm, 64%) as a white solid. MS (M+l) = 506 m/z H NMR (CDC13, 5) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, 1H ), 7.01(dd,lH ), 6.74 (t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, 1H), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91 (m,4H), 2.60(t, 2H). Example 8 Preparation of (S) -N-[[3- (3-fluoro-4-morpholinylphenyl) -2-oxo-5- oxazolidinyl ] methyl] -4- oxo -4-(2- thienyl)butanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml) . To this was added 4 - oxo - 4 (2 - thienyl)butanoic acid (0.125gm, 0. 00068 moles) and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the resulting mixture was allowed to warm to room temp and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated sodium bicarbonate was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separatedand the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.175 gm, 56%) as a white solid MS (M+1) = 462 m/z 28 lH NMR (CDC13, 8) : 7.63(d,lH ), 7.55 (dd,lH ), 7.35(dd,lH), 7.04(t, like dd, 2H), 6.83(t,lH), 6.30 (t,lH), 4.69(m,lH), 3.93 (t, 1H), 3.6- 3.8 (m, 3H),3.80 (m,4H), 3.61(dd, 2H), 3.21(dd,2H),2.97 (m,4H),2.55(t, 2H). Example 9 Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( V- methyl - 4 - propylphenyl) - 4 - oxobutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 -oxo - 5 -oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml). To this was added 4 - [ 4(2'-methylpropylphenyl)]- 4 - oxobutanoic acid (0.158gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated, and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.210gm, 60%) as a white solid. MS(M=l) = 512m/z 'H NMR (CDC13, 8) : 7.73(d,2H ), 7.52 (dd,lH ), 7.28(m,lH ),7.15(d,2H ), 7.05 (d,lH), 6.39 (t,lH), 4.75(m,lH), 3.91 (m, 4H), 3.5- 3.9 (m, 4H), 3.28 (dd, 2H), 3.16 (m,4H),2.54 (t, 2H), 2.45 (d, 2H), 1.82 (pent., 1H), 2.60 (t, 2H). Example 10 Preparation of(S) -N-[ [3 - (3 -fluoro -4- morpholinylphenyl) - 2 -oxo - J - oxazolidinyl J methyl J -4- oxo - 4 -(4- thiomethyl) phenylbutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF -water mixture (20 ml). To this was added 4 - (4-methlythiophenyl) - 4 - oxobutanoic acid (0.152g, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) and the resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142g, 0.00074 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate was added to, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The 29 combined fractions were concentrated to give the title compound (0.270 gm, 79%) as a white solid. MS (M+l) = 502 m/z JH NMR (CDC13, 5) : 7.70(d,2H ), 7.37 (dd,lH ), 7.14(d,2H ), 7.00 (dd,lH), 6.79(t,lH), 6.38 (t,lH), 4.71(m,lH), 3.86(t,lH),3.5- 3.9 (m, 4H), 3.81 (m, 4H), 3.22 (dd, 2H), 2.96 (m,4H),2.53 (t, 2H), 2.45(s,3H). Example 11 Preparation of:. (S) - N-[[3 - (3 -fluoro -4- morphottnylphenyl) — 2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) - 4 - oxobutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.100gm, 0.00034 moles) was taken up in 1:1 THF-water mixture (20 ml) . To this was added 4 - (4- chlorophenyl) - 4 - oxobutanoic acid(0.072g, 0.00034 moles and HOBt (0.046g, 0.00034 moles) .The resulting mixture was cooled to 0°C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.071gm, 0.00037 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated and 2 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with dichloromethane. The organic layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give (0.070gm, 42%) of the title compound as a white solid. MS (M+l) = 490 m/z JH NMR (CDCI3, 8) : 7.72(d,2H ),7.37 (dd,lH ),7.31(d,2H ), 6.98 (dd,lH),6.79 (t,lH), 6.28 (t,lH), 4.69(m,lH), 3.83 (t, 1H), 3.81 (m, 4H), 3.4- 3.m (m, 3H), 3.21 (dd, 2H), 2.97 (m,4H),2.54 (t,2H). Example 12 Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 -naphthyl) - 4 - oxobutanamide - N - oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (2 -naphthyl) - 4 - oxobutanamide (0.950gm, 0.0019 moles) in dichloromethane (150 ml) was added 60% m -CPBA (0.550g, 0.0032 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The column was eluted with ethyl acetate (200 ml), followed by a mixture of chloroform : methanol 30 (4:1,600 ml).Concentration the combined fractions gave the title N-oxide (0.891g, 82% ) as a white solid. !H NMR (CDCI3, 8) : 8.59(t,lH ), 8.36(s,lH),7.7-7.9 (m,5H), 7.2 -7.5 (m,2H),7.08 (dd,lH), 6.60(t,lH), 4.76(m,lH), 4.61(bt,2H), 3.5 - 4.3 (m, 9H), 3.42 (dd, 2H), 2.83 (bdd,2H), 2.61 (bt, 2H). Example 13 Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide. To a cooled solution (0 - 5° C) of (S) - N -[[3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - oxo - 4 - (2 - thienyl)butanamide (0.850gm, 0.0017moles) in dichloromethane (120 ml) was added 60% m -CPBA (0.550g,0.0032 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The column was eluted with ethyl acetate (200ml) followed by a mixture of chloroform : methanol (4:1,600 ml).Concentration of the combined fractions gave the tile N-oxide (0.790g, 90%) as a white solid. 1HNMR( CDCI3,5) : 8.63(t,lH), 7.77(dd,lH), 7.65 (d, 1H), 7.56 (d, 1H), 7.09 (dd, 1H),7.04 (dd,lH), 6.45(t,lH), 4.68(m,lH), 4.65(bt,2H), 4.22 (dt,2H), 3.89(t,lH), 3.5 - 3.9 (m, 5H), 3.22 (dd, 2H), 3.00 (bd,2H), 2.54 (t, 2H). Example 14 Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) -4- oxobutanamide -N- oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide, (1.150gm, 0.0023 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.725gm, 0.0040 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1,600 ml). Concentration of the combined fractions gave the title N-oxide (0.950g, 80%) as a white solid. 'HNMRtCDCk 8) : 8.61(t,lH ), 7.76(d,2H), 7.72 (dd, 1H), 7.34 (d, 2H), 7.10 (dd, 1H), 6.46(t,lH), 4.70(m,lH), 4.64(bt,2H), 4.16 (dt,2H), 3.94(t,lH), 3.5 - 3.9 (m, 5H), 3.24 (dd, 2H), 2.97 (bd,2H), 2.55 (t, 2H). 31 Example 15 Preparation of(S) -N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo -5-oxazolidinyl ] methyl] -4-/4-(2'- methyl - 4 -propylphenyl) -4 — oxobutanamide -N- oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - [4 - (2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide (1.05gm, 0.0020 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.600gm) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1 , 600 ml). Concentration of the combined fractions gave the title N-oxide (0.891gm, 82%) as a white solid. JH NMR (CDC13, 5) : 8.62(t,lH ), 7.77(dd,lH), 7.75 (d, 2H), 7.14 (d, 2H), 7.12 (dd, 1H), 6.44(t,lH), 4.75(m,lH), 4.64(bt,2H), 4.20 (dt,2H), 3.95(t,lH), 3.91 (t,lH) 3.5-3.9 (m, 4H), 3.26 (dd, 2H), 2.99(bd,2H), 2.57 (t, 2H),2.44(d,2H), 0.83(d,6H). Example 16 Preparation of (S)-N-ff3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4- methylphenyl)-4-thiooxobutanamide To a solution of (S)-n- of (S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4-methylphenyl)-4-oxo-butanamide (0.1 Ogm, 0.00021 moles) in dry THF (5ml) was added Lawessons Reagent (0.052gm, 0.000128 moles) and the resulting solution heated under reflux for 8 hr. The reaction mixture was cooled to room temperature and to this was added saturated aqueous sodium carbonate solution (3ml) and then extracted with ethyl acetate. The solvent was evaporated off and the residue chromatographed over silica gel and eluted with a mixture of ethyl acetate-hexane to give the title compound (0.023 gm, 23%) as a white solid, mp 149-151° C. lH NMR (CDCI3,5) : 8.60 (m, 1H), 7.68 (d, 2H), 7.34 (dd, 1H), 7.14 (d, 2H), 6.96 (dd, 1H), 6.81 (t, 1H), 4.90 (m, 1H), 4.20-4.40 (m, 1H), 3.80-4.0 (m, 4H), 3.50 (m, 2H), 2.90-3.00 (m, 6H). Example 17 Using the appropriate amine compound (II) and the carboxylic acid (HI) and following exactly the method described in Examples 7-16 the following carboxylic acids can be prepared, viz. (S) - N-[ [ 3 - (3-fluoro — 4- morpholinylphenyl) -2- oxo — 5- oxazolidinyl J methyl] — 4-(4- methylphenyl) -4- oxobutanamide. 32 'H NMR (CDCI3, 5) : 7.78 (d, 2H ), 7.44 ( d, IH ), 7.22 ( d,2H ), 7.09 ( d, IH ), 6.88 ( t, IH ), 6.41(t, IH), 4.76 (m, IH ), 3.6 - 4.1 (m, 4H ), 3.86 ( m, 4H ), 3.31 ( dd, 2H ), 2.61 (t, 2H ), 2.40 (s.3H). (S) -N-[[ 3-(3 -fluoro -4 - benzylpiperazinyl) phenyl] -2- oxo - 5 - oxazolidinyl] methy ] -4-oxo -4-phenylbutanamide. lH -NMR (CDC13, 5) : 7-88 ( d,2H ), 7.61 (dd, IH), 7.38 ( m, 5H ), 7.2 - 7.4 (m, 5H), 6.88 (t, IH ), 6.55 (t, IH ), 4.77 ( m, IH), 3.94 (t, IH), 3.5 - 3.7 (m, 3H ), 3.71 ( s, 2H ), 3.34 (dd, 2H ), 3.12 (m, 4H),3.12 (m, 4H ), 2.61 (t, 2H ). (S) - N-f]3 - ( 3 -fluoro - 4 - [methylbenzylamin]phenyl) - 2 - oxo -5 - oxazolidiny] methy ]-4-(4- methyl phenyl) -4- oxobutanamide. H NMR (CDCI3, 8) : 7.90 ( d, 2H ), 7.52 ( dd, IH ), 7.2 - 7.5 ( m, 8H ), 7.05 ( d, IH ), 6.84 (t, IH ), 6.50 (t, IH ), 4.75 (m, IH ), 4.48 (s, 2H ), 3.95 (t, IH), 3.6 - 4.1( m,3H ), 3.64 ( dd, 2H ), 2.71 (s,3H), 2.62 (t,2H). (S)-N-[[3-(3-fluoro-4- benzotriazolylpheny)-2-oxo-5-oxazolidinyl]methy]-4-oxo - 4 -phenylbutanamide. !H NMR ( CDCI3, 5) : 8.16 ( d,lH), 7.84 (d, 2H), 7.66 (t, IH), 7.2 -7.6 (m, 8H), 6.46 (t, IH ), 4.90 (m, IH), 3.98 (t,lH), 3.9 - 4.0 (m, 2H ), 3.65 (m, IH ), 3.39 (ddd, 2H ), 2.65 ( ddd, 2H). (S) -N-[[3-(3-fluoro-4- pyrrolidinylphen) -2-oxo-5- oxazolidinyl]methyl]-4-oxo - 4 -phenylbutanamide. !H NMR (CDCI3, 8) : 7.90 (d,2H ), 7.52 (dd, IH ), 7.44 (d, 2H ), (dd, IH ), 7.04 (dd, IH), 6.65 (t, IH), 6.43 (t, IH), 4.74 (m,lh), 3.93 (t,lH), 3.77 (t,lH), 3.6 3,8 (m, 2H), 3.33 (m, 6H ), 2.63 (t, 3H), 1.94 (m,4H). (S)-N-[[3-(3-fluoro-4- benzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methy]-4-(4- methlyphenyl) - 4- oxobutanamide. !HNMR (CDCU, 8) : 8.16 (d, IH ), 7.3 - 7.9( m,7H), 7.78 (d,2H ), 7.21(d,lH), 6.54(t, IH), 4.89 ( m, IH), 3.8 -42 (m, 3H ), 3.4 - 3.7 (m, 3H ), 2.63 (dd, 2H ), 2.23 (s, 3H ). (S)-N-][3-(3 -fluoro - 4 - thiomorpholinylphenyl) -2 — oxo - 5 - oxazolidinyl] methyl] -4- oxo- 4 -phenylbutanamide. !H NMR (CDCI3, 8) : 7.89 (d, 2H ), 7.39 - 7.60 ( m, 4H ), 7.11 (dd, IH ), 6.90 (t, IH), 6.39 ( t,lH ), 4.76 (m,lH ), 3.94 (t,lH ), 3.80 (t, IH ), 3.6 - 3.7 ( m, 2H ), 3.36 ( dd, 2H ), 3.28 ( m,4H), 2.80 ( m,4H ), 2.62 (t, 2H). (S) — N-[[3 - (3 -fluoro - 4 - benzylpiperazinyl) phenyl] — 2 — oxo — 5 - oxazolidinyl] methyl]- 4-(4- methylphenyl) -4- oxobutanamide. 33 H NMR (CDCI3, 5) : 7.81 ( d, 2H), 7.2 - 7.5 ( m, 8H ), 7.08 (dd, IH ), 6,89 (t, IH ), 6.39 (t, IH ), 4,78 ( m, IH ), 3.95( t, IH), 3.79 (t, IH), 3.6 - 3.7 (ni, 2H ), 3.61(s, 2H), 3.31 ( m,2H), 3.09 (m,4H), 2.65 (m,6H), 2.41 (s, 3H). (S)-N-[[3-(3-fluoro-4- piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl]-4- oxo - 4 - phenylbutanamide. !H NMR (CDCI3, 8) : 7.90(d,2H ),7.60 (dd,lH ),7.45(d,2H ), 7.39 (dd,lH), 7.10 (dd,lH), 6.90 (t,lH), 6.55 (t,lH), 4.78(m,lH), 3.95 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.35 (m, 2H), 3.00 (m,4H0,2.63 (t, 2H), 1.9-1.6 (m,6H). (S)-N-[[3- (3 -fluoro-4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4-(4 - methylphenyl) - 4- oxobutanamide. JH NMR (CDCI3, 5) : 7.79(d,2H ),7.40 (dd,lH ),7.23(d,2H ), 7.09 (dd,lH), 6.91 (t,lH), 6.40 (t,lH), 4.77(m,lH), 3.98 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.30(t, 2H), 2.98 (m,4H), 2.62 (t, 2H),2.41(s,3H), 1.6-1.9 (m,6H). (S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5- oxazolidinyl] methyl]- 4 -(4- methylphenyl) - 4- oxobutanamide. 'H NMR (CDCI3, 8) : 7.80(d,2H ),7.32 (dd,lH ),7.21(d,2H ), 7.01 (dd,lH), 6.60 (t,lH), 6.40 (t,lH), 4.75(m,lH),4.12(m,lH) 3.94 (t, IH), 3.75 (t, IH), 3.4- 3.6 (m, 2H), 3.34 (m, 6H), 2.61 (t, 2H),2.40(s,3H), 1.9(m,4H). (S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4 -(4- methoxyphenyl) -4- oxobutanamide. lU NMR (CDCI3, 8) : 7.79(d,2H ),7.36 (dd,lH ), 7.00 (dd,lH), 6.82 (d,2H), 6.80(t,lH), 6.38 (t,lH), 4.69(m,lH), 3.80 (s, 3H), 3.78 (m, 4H), 3.4- 4.0 (m, 4H), 3.20 (dt, 2H), 2.97 (m,4H),2.55 (dt,2H). (S) -N-[[3-(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4- (2 -naphthyl) -4- oxobutanamide. !H NMR (CDCI3, 8) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, IH ), 7.01(dd,lH ), 6.74 (t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, IH), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91 (m,4H), 2.60(t, 2H). ((S) - N -[[ 3 - (3 -fluoro -4- morpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4- (2, 4-difluorophenyl) -4-oxobutanamide. !H NMR (CDCI3, 8) : 7.73(ddd,2H ), 7.47 (dd,lH ), 7.01(dd,lH ),6.7 - 6.9(m,3H ), 6.30 (t,lH), 4.75(m,lH), 3.89 (m, 4H), 3.5- 3.9 (m, 4H), 3.20 (m, 2H), 3.09(m,4H), 2.52 (t, 2H). (S)-N -[[ 3-(3 -fluoro -4- morpholinylphenyl) -2- oxo -5— oxazolidinyl] methyl] - 4 -[4- (2s',2'- dimethyl- 4 - ethylphenyl) -4- oxobutanamide. 34 !H NMR (CDC13, 8) : 7.75(d,2H ), 7.37 (d,2H ), 7.35(dd,lH ), 7.05 (dd,lH), 6.82(t,lH), 6.37 (t,lH), 4.71(m,lH), 3.5- 3.9 (m, 4H), 3.80 (m, 4H), 3.25 (dt, 2H), 2.97 (m,4H),2.54 (t, 2H), 1.26(s,9H). (S) -N-ff 3 - (3 -fluoro - 4 -fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] -4-(4- methoxyphenyl) -4- oxobutanamide. lU NMR (CDC13, 8) : 7.76(d,2H ), 7.37 (dd,lH ), 7.16(m,5H ), 6.93 (dd,lH), 6.79(d,2H),6.74 ( t,lH), 6.37 (t,lH), 4.66(m,lH),4.14 (s,2H), 3.84(t,lH), 3.74 (s,3H), 3.4- 3.8 (m, 3H), 3.18 (dd, 2H), 2.62(s,3H),2.5 l(t, 2H). (S) -N-ff 3 - (3 -fluoro - 4 - fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl] methy] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide. 'H NMR (CDCU, 8) : 7.77(d,2H ), 7.37 (dd +d,3H ), 7.19 -7.22(m, 3H), 6.98 (dd,lH), 6.77(t,lH), 6.31 (t,lH), 4.69(m,lH), 4.17(s,2H), 3.89(t,lH)„3.72 (dd,lH), 3.5- 3.6 (m, 2H), 3.25 (dd, 2H), 2.64 (s,3H),2.55 (t, 2H), 1.25(s,9H). (S) -N-ff 3 -(3 -fluoro - 4 -[methylbenzylamino]phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] -4- (2,4 - dimethylphenyl) -4- oxobutanamide. lU NMR (CDCI3, 8) : 7.65(d,lH ), 7.46 (dd,lH ), 7.32(m,5H ), 7.04(m,3H), 6.95(t,lH), 6.36 (t,lH), 4.78(m,lH), 4.27(s,2H), 3.97(t,lH),3.6- 3.8 (m, 2H), 3.81 (t, IH), 3.27 (dd, 2H), 2.77 (s,3H),2.61 (t, 2H), 2.44(s,3H), 2.35 (s, 3H). (S)-N -[[ 3-(3 -fluoro -4- tnorpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] - 4 - (2,4 - dimethylphenyl) -4- oxobutanamide. 'H NMR (CDCU, 8) : 7.652(d,lH ), 7.42 (dd,lH ), 7.0- 7.1(m,3H), 6.86(t,lH), 6.38 (t,lH), 4.79(m,lH), 3.95(t,lH),3.5- 3.9 (m, 2H), 3.87 (m, 4H), 3.25(dd, 2H), 3.02 (m,4H), 2.59 (t, 2H), 2.41(s,3H), 2.34 (s, 3H). ^ -N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) —2 — oxo -5 — oxazolidinyl] methyl] — 4 — (2,4 - dimethylphenyl) - 4 - oxobutanamide. JH NMR (CDCI3, 8) : 7.62(d,lH ), 7.31 (dd,lH ), 7.03(s,+dd, 3H ), 6.60(t,lH), 6.36 (t,lH), 4.74(m,lH), 3.94(t,lH), 3.76 (dd, lH),3.67(m, 2H), 3.30 (m, 4H), 3.24 (dt, 2H), 2.60 (t, 2H), 2.44(s,3H), 2.34 (s, 3H).1.94 (m,2H). (S) -N-ff 3-(3-fluoro-4- benztriazolylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4- (2,4- dimethylphenyl) -4-oxobutanamide. !H NMR (CDCI3, 8) : 8.15(d,lH ), 7.80 (dd,lH ), 7.3 -7.7(m,6H ), 7.02(d,2H), 6.39 (t,lH), 4.87(m,lH), 4.07(t,lH), 3.96(t,lH), 3.89 (dq, IH), 3.75(dt,lH), 3.38 (qt, 2H), 2.62 (m, 2H), 2.39(s,3H), 2.26 (s, 3H). (S) - N-ff 3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4- oxo -4-(2- thienyl)butanamide. 35 H NMR (CDC13, 8) : 7.71(d,lH ), 7.63 (d,lH ), 7.31(dd,lH ), 7.11 (t, lH),7.05(dd,lH), 6.68(m,lH), 6.38 (t,lH), 4.74(m,lH), 3.95(t,lH), 3.77 (t, 1H),3.6- 3.7 (m, 2H), 3.36 (m, 4H), 3.28 (t, 2H), 2.63 (t, 2H), 1.96 (m,2H). (S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo - J - oxazolidinyl] methyl] - 4 - oxo -4-(2- thienyl)butanamide. !H NMR (CDC13, 8) : 8.08(d,lH), 7.77(dd,lH ), 7.3 - 7.7(m,7H ), 7.02(t,lH), 6.45 (t,lH), 4.81(m,lH), 4.00(t,lH),3.7- 4.0 (m, 2H), 3.57 (dt, 1H), 3.25 (m, 2H), 2.55 (m,2H). (3? -N-[[3-(3-fluoro-4- morpholinylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4- oxo - 4 -phenylbut - 2- enamide. JH NMR (CDCI3, 8) :7.92 (d,lH), 7.84 (,d,lH), 7.2 - 7.6 (m, 6H), 6.98 - 7.1 (m, 3H), 4.38(m, 1H), 3.5 - 4.1 (m, 4H), 3.84 (m, 4H), 3.03 (m, 4H). (S) -N-[[3-(3 -fluoro-4- piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4-(4 - methoxyphenyl) - 4- oxobutanamide. 'HNMR^MSOde, 8) : 8.25 (t, 1H), 7.79 (d, 2H), 7.38 (dd, 1H), 7.71 (dd, 1H), 6.95 (t,lH), 6.93 (d, 2H + 1H), 4.65 (m,lH), 3.75 (s,3H), 3.99 (t, 1H), 3.64 (dd, 1H), 3.06 (t, 2H), 2.81(m,4H), 1.3 -1.6(m.6H). (S) -N-[[3-(3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4 - chlorophenyl) - 4- oxobutanamide. lH NMR (CDCI3, 8) : 7.73(d,2H ), 7.33 (d,2H ), 7.2 - 7.8 (m, 2H),6.96(dd,lH), 6.34 (t,lH), 4.72(m,lH), 3.84(t,lH), 3.5- 3.8 (m, 3H), 3.21 (dd, 2H), 2.98 (m, 4H),2.54(t,2H), 1.5 - 1.7 (m,6H). (S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl] -4-(2,4 - dimethylphenyl) - 4- oxobutanamide. 'H NMR (CDCI3, 8) : 7.55(d,2H ), 7.4 (m,lH ), 6.9 - 7.0 (m, 3H),6.32(t,lH), 4.70(m,lH), 3.90(t,lH), 3.74 (t,lH), 3.5- 3.7 (m, 2H), 3.20 (dd, 2H), 2.9 - 3.1 (m, 4H),2.52(t,2H), 2.34 ( s,3H), 2.71 (s, 3H ), 1.5 -1.9 (m,6H). (S) - N-[[3 - (3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- methoxyphenyl) -4-oxobutanamide. XH NMR ( CDCI3, 8) : 8.07(d, 1H), 7.2 - 7.8 (m,6H), 7.71(d,2H ), 6.79 (d,2H ), 6.51(t,lH), 4.81(m,lH), 3.4- 4.0 (m, 4H), 3.71 (s, 3H), 3.15 (qt, 2H), 2.52 (dd, 2H). (S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- chlorophenyl) -4-oxobutanamide. 'H NMR (CDCI3, 8) : 8.09(d, 1H), 7.2 - 7.8 (m,6H), 7.75(d,2H ), 7.35 (d,2H ), 6.29(t,lH), 4.81(m,lH), 3.7 - 4.0(m, 3H), 3.5 - 3.7 (bt, 1H),3.25 (qt, 2H), 2.55 (t, 2H). (S)-N-[[3-(3-fluoro-4-(1,2,4-triazolyl)phenyl)-2-oxo-5- oxazolidinyljmethyl] -4- oxo — 4 - phenylbutanamide. 36 H NMR (CDCI3, 8) : 8.62 (bs, 1H ), 8.10 ( s, 1H ), 7.7 -7.8 ( m, 2H ),, 7.67 (dd, 2H, ), 7.44 (t, 1H ), 7.2 - 7.4 (m,3H ), 6.49 (t, 1H ), 4.78 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55 (dt, 1H ), 3.30 (ddd, 2H), 2.54 (dd, 2H). (S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4- methylphenyl) -4- oxobutanamide. XHNMR (CDC13, 8) : 8.71 (bs, 1H ), 8.10 ( s, 1H), 7.7 -7.9 ( m, 4H ), 7.30 (d, 1H, ), 7.21 (d, 2H ), 6.63 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.64(dt, 1H ), 3.35 (qdd, 2H), 2.5 - 2.6 (m, 2H), 2.35( s,3H). (S) - N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] - 4-(4- methoxyphenyl) -4- oxobutanamide. 'H NMR (CDCI3, 8) : 8.68 (bs, 1H ), 8.16 ( s, 1H ), 7.7 -7.9 ( m, 2H ), 7.79( d, 2H ) 7.28 (dd, 1H), 6.85 ( d,2H), 6.58 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.82(s,3H), 3.61(dt, 1H ), 3.32 (qdd, 2H), 2.65 (ddd, 2H). (S) -N-][3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl] -4-(2,4- dimethylphenyl) -4- oxobutanamide. !HNMR (CDCI3,8) : 8.69 (bs, 1H ), 8.17 ( s, 1H ), 7.78( t,lH), 7.75 ( d,lH ), 7.60 (d,lH),7.25(d, 1H, ), 7.10 (d, 1H ),6.99(s, 1H ), 6.54( t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.65(dt, 1H ), 3.25 (qt, 2H), 2.59 (dt, 2H), 2.38( s,3H), 2.29 (s,3H). (S) -N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4- oxo- 4 -(4 - thiomethylphenyl)butanamide. 'H NMR (CDCI3, 8) : 8.57 (bs, 1H ), 8.06 ( s, 1H ), 7.77 (m,2H), 7.61 (d, 2H), 7.19 ( d, 1H ), 7.10 (d, 2H, ), 6.47 (t, 1H ), 4.76 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25 (qdd, 2H), 2.55 (dq,2H),2.39(s,3H). (S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide. lU NMR (CDCI3, 8) : 8.58 (bs, 1H ), 8.06 ( s, 1H ), 7.80(t,lH),7.6 -7.8 ( m, 1H ), 7.67 (d, 2H,),7.32(d,2H), 7.26 (d, 1H ), 6.43 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25 (qt, 2H), 2.53(dt, 2H), 1.22( s,9H). (S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(2'- methyl - 4 - propylphenyl) -4- oxobutanamide. 'H NMR (CDCI3, 8) : 8.61 (bs, 1H ), 8.09 ( s, 1H ), 7.6 -7.8 ( m, 4H ), 7.24 (dd, 1H, ), 7.07 (d, 2H ), 6.38 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.54(dt, 1H ), 3.28(qt, 2H), 2.54(dt, 2H), 2.40( d,2H), 1.77 (pent.,lH), 0.81 (d,6H). (S) - N-[[ 3-(3 -fluoro -4- (1,2,4 — triazolyl) phenyl) -2- oxo -5— oxazolidinyl] methyl] -4-oxo - 4- (2- thienyl)butanamide. 37 'HNMR (CDCI3, 8) : 8.57 (bs, IH ), 8.05 ( s, IH ), 7.76 (t,lH),7.60(dd,lH), 7.53 (dd,lH), 7.25 (dd, IH, ), 7.01 (d, 2H ), 6.47( t, IH ), 4.78 ( m, IH), 3.7 - 4.0 (m, 3H), 3.56(ddd, IH ), 3.25 (qt, 2H), 2.54 (dt, 2H). (S) -N-[[3 -(3 -fluoro -4- (1,2,4-triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl]- 4 - (2-naphthyl) -4- oxobutanamide. !H NMR (CDCI3, 8) : 8.41 (s, IH ), 8.27( s, IH ), 8.02(s,lH), 7.3 -7.9 ( m,6H ), 7.3 - 7.6 (m, 3H), 6.44 (t, IH ), 4.77 ( m, IH), 3.7 - 4.0 (m, 3H), 3.2- 3.7 (m, 3H), 2.5-2.6 (m, 2H). (S) - N-[[3 - (3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4- chlorophenyl) -4- oxobutanamide. lH NMR (CDCI3, 8) : 8.58 (bs, IH ), 8.07 ( s, IH ), 7.6 -7.9 ( m, 2H ), 7.68 (d, 2H), 7.29 (d, 2H,), 7.2 - 7.3 (m, IH ), 6.31 (t, IH ), 4.81 ( m, IH), 3.7 - 4.1 (m, 3H), 3.55(dt, IH ), 3.25 (qt, 2H), 2.55(dt, 2H). (S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4- oxo -4-(2- thienyl)butanamide. H NMR (CDCI3, 8) : 7..5 - 7.7 ( m, 2H), 7.3 - 7.5 (m,lH), 6.8 - 7.3(m,3H ), 6.35(t,lH), 4.69(m,lH), 3.89 (t,lH), 3.76(t,lH),3.59(m,2H), 3.21(dd,2H),3.02 (m, 4H), 2.55 (t, 2H), 1.5 - 1.8 (m,6H). (S) -N-[[3 -(3-fluoro -4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4- (2'- methyl -4- propylphenyl) -4- oxobutanamide. 'H NMR (GDCI3,8) : 8.08 (m, IH ), 7.74 (d, 2H), 7.4 - 7.8 (m, IH ), 7.16 (d, 2H,), 6.97(dd,lH) 6.37 (t, IH ), 4.74 ( m, IH), 3.88 (t, IH), 3.80(t,lH), 3.4 - 3.71 (m, 2H), 3.40(m,4H) 3.25(dd, 2H ), 2.45(d, 2H), 1.80 (pent, IH), 1.5-1.8(m,6H),0.83(d,6H). (S)-N-[[3-(3-fluoro-4-piperidylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(4 - acetamidophenyl) -4- oxobutanamide. 'H NMR (DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.78 (d, 2H), 7.60 ( d, 2H), 7.36 (dd, IH), 7.06 (dd, IH), 6.93 (t,lH), 4.63 (m, IH), 3.95(t,lH), 3.61 (dd,lH), 3.07(dd,lH), 2.81 (m,4H), 1.99 (s, 3H), 1.55 (m, 4H), 1.44 (m, 2H). (S) - N-ff 3 -( 3 -fluoro - 4 piperidylphenyl) - 2 - oxo - J - oxazolidinyl] methyl] -4- oxo - 4 -phenylbut - 2- enamide. JHNMR (CDCI3, 8) .-7.7-8.0 (m,3H), 7.2 - 7.6 (m, 5H), 7.01 (d,2H), 6.98 (t, IH), 4.80(m, IH), 4.01(t,lH), 3.85(t,lH), 3.77 (t, 2H), 3.16 (m, 4H), 1.5 - 1.9 (m,6H). (S) - N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] ~4- oxo- 4-(4- thiomethylphenyl)butanamide. lU NMR (CDCI3, 8) :7.70 (d,2H), 7.60 (bd,lH), 7.0 - 7.3 (m, 3H), 6.91 (d,lH), 6.47 (t, IH), 4.71(m, IH), 3.87(t,lH), 3.4 - 3.8 (m,3H ), 3.45(m, 4H) 3.21 (dd, 2H), 2.54 (t, 2H), 2.45 (s,3H), 2.06(m,4H). 38 (S)-N-[[3-(3-fluoro-4-pyrrolidinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(2-naphthyl) -4- oxobutanamide. !H NMR (CDC13, 8) : 8.35 (s, IH ), 7.5 - 8.1 (m, 8H ), 6.91(d,lH) 6.53 (t, IH ), 4.72 ( m, IH), 3.38 (m, 4H), 3.2 - 4.0 (m, 6H), 2.61(m, 2H), 1.99 (m,4H). (S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] — 4 — (2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide. lU NMR (CDCI3, 8) :7.75 (d,2H), 7.46 (m,lH), 7.1 - 7.3 (m, 3H), 6.95 (d,lH), 6.44 (t, IH), 4.70(m, IH), 3.3 - 4.0 (m,4H ), 3.41(m, 4H) 3.24 (dd, 2H), 2.55 (t, 2H), 2.45 (d,2H), 2.01(m,4H), 1.81 (pent,lH), 0.83 (d, 6H). (S) -N-][3-(3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4- (2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide. lH NMR (CDCI3, 8) :7.76 (d,2H), 7.2 7.5(m, 4H), 6.95 (d,lH), 6.33 (t, IH), 4.69(m, IH), 3.88(t,lH), 3.71(t,lH), 3.6 - 3.7 (m,2H ), 3.45(m, 4H) 3.23 (dd, 2H), 2.56 (t, 2H), 1.94 (m,4H), 1.26(s,9H). (S^J - N-[[3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4 — (4 - acetamidophenyl) -4- oxobutanamide. 'H NMR (CDCU, 8) : 7.2 - 7.8 (m, 7H), 6.85 (d,lH), 6.47 (t, IH), 4.67(m, IH), 3.81(t,lH), 3.3 - 3.7 (m,3H ), 3.46(m, 4H) 3.16 (m, 2H), 2.3 - 2.9 (m,6H), 2.06(s,3H). (Sp -N-[]3-(3-fluoro -4- pyrrolidinylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4- oxo - 4 -phenylbut - 2- enamide. 'HNMR (CDCI3, 8) :7.8 - 7.9 (m,3H), 7.0 - 7.6 (m, 5H), 6.93 (d,lH), 6.75 (m,lH), 4.76(m, IH), 4.02(t,lH), 3.74 (m, 3H), 3.30 (m, 4H), 1.95 (m,4H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]- 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. !HNMR (CDCI3, 8) :7.78 (d,2H), 7.33 (dd,lH),6.99 (d,lH), 6.83 (t,lH), 6.81 (d, 1H),6.38 (t, IH) 4.69(m, IH), 3.86 (t,lH), 3.79 (s,3H), 3.5 - 3.8 (m,3H ), 3.41(m, 4H) 3.20 (m, 6H), 2.73(m,4H) 2.53 (t, 2H). (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5- oxazolidinyl]methyl]- 4 - (2,4 - dimethylphenyl) -4- oxobutanamide. !H NMR (CDCI3, 8) :7.55 (d,lH), 7.33 (dd,lH), 6.96 (m,3H), 6.81(t,lH), 6.22 (t, IH), 4.69(m, IH), 3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.17(m, 6H) 2.73 (t, 2H), 2.45 (d,2H),2.51 (t,2H), 2.34(s,3H), 2.27 (s,3H). (Si)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]- 4 - oxo -4-(2- thienyl)butanamide. !H NMR (CDCI3, 8) :7.63 (d,lH), 7.55 (d,lH), 7.33 (dd, IH), 7.05 (dd,2H), 6.85(t, IH), 6.31 (t,lH), 4.69(m, lH),3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.23(m, 6H) 2.73 (m, 4H), 2.55 (t, 2H). 39 (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - J - oxazolidinyl] methyl] -4-(4- acetamidophenyl) -4- oxobutanamide. 'HNMR ( DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.73(d, 2H), 7.59 (d, 2H), 7.38 ( dd, IH), 7.08(dd,lH), 6.99 (t, IH), 4.65 (m, IH), 3.95(t,lH),3.62(dd,lH), 3.08(m, 6H), 2.66 (m, 4H), 1.97 (s,3H). (S) - N -[[ 3 - (3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] - 4 -oxo - 4 - (4 - thiomethylphenyl)butanamide. •HNMR (CDC13,8) : 7.70 (d, 2H), 7.32 (dd,lH),7.14 (d, 2H,), 6.99(dd,lH), 6.82(t,lH), 6.33 (t, IH ), 4.68 ( m, IH), 3.86 (t, IH), 3.4 - 3.8 (m, 3H), 3.20(dt, 2H ), 2.90(t,4H) 2.53(t, 2H), 2.44(s,3H), 1.67 (m,4H), 1.5 (m,2H). (S) -N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl] -4-(naphthyl) -4- oxobutanamide. 'H - NMR ( CDCI3) : 8.36 (s, IH ), 7.7 - 7.9 (m, 4H, ), 7.4 - 7.6 (m, 2H ), 7.32 (dd,lH), 6.99(d,lH), 6.78(t,lH), 6.43 (t, IH), 4.70 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.39(dt,2H), 2.86(t,4H), 2.61(t, 2H), 2.10(m,4H),1.50 (m,2H). S) -N-[[ 3- (3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide. lUNMR (CDCI3,8) : 7.75 (d, 2H), 7.37 (d,2H),7.31 (dd, IH, ), 7.00(dd,lH), 6.84(t,lH), 6.37 (t, IH ), 4.68 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.25(dt, 2H ), 2.91(t,4H) 2.54(t, 2H), 2.23(m,4H), 1.5 (m,2H), 1.26(s,9H). (S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4-oxo -4-(4- thiomethylphenyl)butanamide. 'HNMR (CDCI3, 8) : 8.08 (d, 2H ), 7.77 (dd, IH, ), 7.63(d,2H), 7.2 - 7.5 (m, 4H ), 7.12 (d,2H), 6.41 (t, IH ), 4.81 ( m, IH), 3.98 (t, IH), 3.7 - 3.9 (m, 2H), 3.54(dt,lH), 3.22(qdd,2H), 2.54(dd, 2H), 2.36(s,3H). (S) -N-[] 3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5 - oxazolidiny] methyl] -4-(2-naphthyl) -4- oxobutanamide. 'HNMR (CDCI3, 8) : 8.35( s,lH), 8.08 (d, IH ), 7.6 - 7.8(tn,5H), 7.2 - 7.6 (m, 7H ), 6.41 (t, IH ), 4.82 ( m, IH), 3.8 - 4.0 (m, 3H), 3.3 - 3.7(m,3H), 2.64(dd, 2H). (S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4 - (2',2' - dimethyl- 4 - ethylphenyl) -4- oxobutanamide. H NMR (CDCI3, 8) : 8.08 (d, IH ), 7.80 (dd, IH, ), 7.70(d,2H), 7.57(t, IH), 7.2 - 7.5 (m, 4H ), 7.08 (d,2H), 6.41 ( t, IH ), 4.80 ( m, IH), 3.7 - 4.0 (m, 3H), 3.55(dt,lH), 3.1 - 3.4(m,2H), 2.54(dd, 2H), 2.37(d,2H), 1.72(pent,lH), 0.76(d,6H). 40 (S)-N-[[3-(3-Jluoro-4- henzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide. JHNMR(CDC13, 5) :7.2 - 8.0 (m,13H), 6.95 (d,lH), 6.65 (m,lH), 4.89(m, IH), 4.18(t,lH), 3.7-4.0 (m, 3H). (S) -N-[[3-(3-Jluoro-4-benztriazolylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 -(4- acetamidophenyl) -4- oxobutanamide. !HNMR (DMSOde, 8) : 10.16 (s, IH), 8.29(t, IH), 8.12 (d, IH), 7.79 (m, 4H), 7.58 ( d, 2H), 7.4 - 7.5 (m, 4H), 4.74 (m, IH), 4.13(t,lH),3.08(dd,lH), 3.10 (t, 2H), 1.97 (s, 3H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide. lH NMR (CDCI3,8) : 7.76 (d, 2H), 7.53 (dd, 1H),7.39 (d, 2H +1H, ), 7.02(d,lH), 6.29 (t, IH ), 4.71 ( m, IH), 3.89 (t, IH), 3.79(t,lH), 3.5 - 3.7 (m, 2H), 3.38(m, 4H ), 3.24 (dd,2H), 2.92(m,4H) 2.54(t, 2H), 1.26(s,9H). (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide. JH NMR (CDCU, 8) :7.8 - 7.9 (m,3H), 7.3 - 7.7 (m, 5H), 6.8 -7.0 (m,3H), 4.81(m, IH), 4.05(m,lH), 3.75 (m, 3H), 3.49 (m, 4H), 3.10 (m,4H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(fi- naphthyl) -4- oxobutanamide. !H NMR (CDCI3, 8) : 8.35 (s, IH), 7.7-8.0 (m, 4H), 7.3-7.7 (m, 5H), 7.01 (m, IH), 6.48 (m, IH), 4.74 (m, IH), 3.80 (m, 3H), 3.60 (m, IH), 3.37 (m, 6H), 2.93 (m, 4H), 2.60 (m, 2H) (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4- (4- chlorophenyl) -4-oxobutanamide. !H NMR (CDCI3, 8) : 7.74 (d, 2H), 7.54 (d, IH), 7.34 (d, 2H+1H), 6.98 (d, IH), 6.35 (t, IH), 4.78 (m, IH), 3.88 (t, IH), 3.5-3.8 (m, 3H), 3.38 (m, 4H), 3.22 (dd, 2H), 2.93 (m, 4H), 2.54 (t, 2H). (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4 - (2,4 - dimethyl- 4 ethylphenyl) -4- oxobutanamide. lH NMR (CDCI3, 8) : 7.95 (m, IH), 7.74 (d, 2H+1H), 7.77 (d, 2H), 7.07 (d, IH), 6.38 (t, IH), 4.76 (m, IH), 3.91 (t,lH), 3.4-3.8 (m, 3H), 3.58 (m,4H), 3.25 (dd, 2H), 3.1 (m, 4H), 2.54 (t, 2H), 2.46 (d, 2H), 1.80 (pent, IH), 0.85 (s, 3H), 0.82 (s, 3H). Microbiology: Pharmacological testing The compound of formula (I) of the present invention displayed antimycobacterial activity when tested by in vitro growth inhibition assay and agar incorporation methods. The minimum inhibitory concentrations (jag/ml) obtained for representative compounds of formula (I) 41 against M. tuberculosis including sensitive and resistant strains are summarized in Table-I. The MIC value of a representative preferred Compound No. 30 of formula I against different species of mycobacteria is summarized in Table-II. in vitro Growth Inhibition assay The ability of the compounds 1-78 of formula (I) of this invention to inhibit the growth of Mycobacterium species was determined by the BACTEC 460 TB system. The reference strain M tuberculosis H37Rv ATCC 27294 was grown in Middlebrook 7H9 broth containing 10% ADC supplement at 37°C on a rotay shaker at 150 rpm for grown for 7days. The turbidity of the culture was adjusted to 1.0 Mc farland. The BACTEC 7H12B medium vials were seeded with 0.1ml of the 1.0 Mc farland adjusted M. tuberculosis culture. In the control vials 0.1ml of the culture was added after lOOfold dilution of the initial inoculum. Stock solution of lmg/ml of each compound was prepared in DMSO in separate sterile tubes. The compounds were further diluted to concentration of 25 ^g/100 ul, 0.1ml was than added to the 7H12B vial containing mycobacterial culture so that final concentration of the compound 6.25 u.g/ml. The cap in all the vials were cleaned with isopropanyl alcohol and kept in racks. The vials were then incubated at 37°C without shaking. Test vials was read daily on the BACTEC system till the GI of the control vial reached > 30.Once the GI in the control reached 30 AGI (GI = GI (n> - GI („.i) ) was determined for all test and control vials. If AGI of test vial is less than that of the control vial the culture was sensitive to the test compound. in vitro Agar Dilution assay MIC of compound of formula (I) of this invention against strains of Mycobacterium were determined by a reference agar dilution method as per the NCCLS- M24-T2. recommendations. The compounds were dissolved in DMSO and diluted twofold to obtain ten serial dilutions of each compound. Appropriate volume of compounds were incorporated into duplicate plates of Middlebrook7H10 agar medium supplemented with 10% Middlebrook supplement oleic acid-albumin-dextrose (OADC) enrichment at concentration of 0.03u,g/ml to 16\|j,g/ml. Test organisms (mycobacterium strains) were grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement. After 7 days of incubation at 37°C the broths were adjusted to the turbidity of 1.0 McFarland standard; the organism were further diluted 10 fold in sterile water containing 0.10% Tween-80. The resulting mycobacterial suspensions were spotted (3-5jxl/spot) onto drug supplemented 7H10 media plates. The plates were sealed and incubated at 37°Cfor 3-4 weeks in upright position. The MIC was recorded as the lowest dilution of the drug that completely inhibited the growth of test organisms. Test isolates included 10 clinical isolates that were generally susceptible to common tubercular agents and 10 strains that were resistant to one or more standard anti tubercular drugs. Appropriate reference strains and control drug was included in each batch of test. 42 in vivo studies: The efficacy of the compound of formula (I) of this invention was also evaluated in murine model of pulmonary tuberculosis. Mycobacterium tuberculosis cultures grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement at 37°C for 7 days on a rotary shaker. For, animal inoculation liquid cultures were declumped by brief sonication and were diluted appropriately in 7H9 broth to obtain a concentration of lxl07CFU's/ 0.2ml. Four-week-old male outbred Swiss albino mice housed in a pathogen free, biosafety level 3 environment within micro isolator cages were used throughout the study. Infections were produced by intravenous inoculation into caudal tail vein of 0.2ml of declumped M. tuberculosis suspension. Following infection, mice were randomly distributed in different groups of six each. Treatment for initial study was started one day after infection. For, treatment Compound No. 30 of formula I was dissolved in 10% PEG. Isoniazid was dissolved in sterile water. The drugs were prepared each morning prior to administration. Therapy was given 5 days per week for four weeks. All the agents were administered by gavage and were dosed at 50,25,12.5mg / kg of body weight. Control group of infected but untreated mice were killed at the initiation of therapy (early control) or at the end of the treatment period (late control). Mice were sacrificed by cervical dislocation 3-5 days after the administration of the last dose of drug. The spleens and right lung were removed aseptically and homogenized in tissue homogeniser. At least 4 serial tenfold dilution of the homogenate was plated onto selective Middlebrook 7H11 agar plates in duplicate. The colony counts were recorded after incubation at 37°C for 4 weeks. The viable cell counts were converted to Logio values. A compound showing 2 Log reduction in viable counts compared to the controls was considered significant. The in vivo data for a representative compound of formula (I) is given in Table-II. Acute toxicity of Compound No. 30 of Chart-I was estimated in mice and the LDo was found to be >1000 mg/kg P. O. 43 Table-I: in vitro activity of compounds 1 to 58 of formula (I), Compound No. Growth inhibition of M.tuberculosis 27294 MIC (fig/ml) against M.tuberculosis 27294 Clinical isolates Sensitive Resistant 1 + 16 4-16 >16 2 + 8 8 8 8 + 2 .5-2 2-4 13 + 2 2 2-4 14 + 0.25 0.25-0.5 4->16 15 + >16 >16 >16 16 + 0.5 0.5 0.5(>16) 17 + 0.5 1.0 0.5-1.0 18 + 4- 1-4 8->16 19 + 2 1-2 2 20 + 1 1-2 2-4 21 + 0.5 0.5-2 0.5(>16) 25 + 4 4-16 4->16 27 + >16 >16 >16 28 + 0.5 1-2 2-8 30 + 0.5 0.5 0.5-2 31 + 1 1-2 1-4 32 + 0.25 0.25-0.5 4-(>16) 33 + 0.5 1 0.5-2 34 + >16 >16 >16 35 + 4 2-4 4-8 36 + 4 4-8 4-8 44 Table-I Contd.... 39 + 2 2-4 2-8 40 + 1 1-2 1-2 43 + 1 0.5-1.0 1-2 44 + 1 0.5-2 1-4 45 . + 2.0 2-4 2-4 46 + 2 2-4 2-8 47 + 1 1-2 2-4 48 + 2 2-4 2-8 49 + 4 4-16 4-16 50 + 2 2-4 2-4 51 + 8 8->16 8->16 52 + 2 2 4->16 53 + >16 >16 >16 54 + 8 8-16 >16 55 + >16 >16 >16 56 + >16 >16 >16 57 + 16 16->16 >16 58 + 8 8-> 16 8-> 16 Isoniazid + 0.25 0.12- .25 8 - >16 Linezolid + 0.5 0.25-0.5 1.0-2.0 Table-II MIC values of compound of formula (I) against different species ofMycobacteria Sr. No. Compound No. MIC (ug/ml) M. tuberculosis M.avium- intracellular complex M.fortuitum M.kansai Sensitive Resistant 1 Compound 30 of formula I 0.50 0.50-2.0 8.0->16.0 >16.0 8.0 2 Isoniazid 0.25 4.0-> 16.0 8.0->16.0 >16.0 >16.0 45 Table-m in vivo activity of Compound of formula (I) against M. tuberculosis ATCC 27294" infection in Swiss albino mice Sr. No. Drug& Dose b (mg/kgday" ') or group Mean Logio No. of CFU Mean Logio No. of reductionc Lung Spleen Lung Spleen 1 Compound 30 of Chart-I 50mg/kg 25mg/kg 12.5mg/kg 2.12 2.21 4.34 2.09 2.13 4.30 2.40 2.30 0.20 2.53 2.49 0.26 2 Isoniazid 50mg/kg 25mg/kg 12.5mg/kg 2.03 2.11 2.95 1.92 2.11 2.94 2.49 2.41 1.57 2.70 2.51 1.68 3 Infected early control 4.52 4.62 4 Infected late control 6.57 6.37 a- inoculation of logio:- 7.00 Mycobacteria. b- mice were dosed 5 day/week for 4 weeks. From day 1 -28. c- difference in mean logio number CFU from that of early controls. The compound of formula I of this invention may be administrated to a subject such as a human being or an animal in need of such an administration through any route appropriate to the condition to be treatede. Suitable routes of administration include oral, rectal, nasal, topical (both buccal and sublingual), vaginal and parenteral (including subcutaneous, intramuscular, intradermal, intrathecal and epidural). Pharmaceutical compositions of compound of formula I can be prepared in adjunction with inert pharmaceutically acceptable carriers, which can either be solid or liquid. Solid form preparations include powders, tablets, dispersible granules, capsules, cachets, suppositories and ointments. The solid carriers can be one or more substances which may act also as diluents, flavouring agents, solubilisers, lubricants, suspending agents, binders or tablet disintegrating agents. It can also be finely divided solid which is in admixture with finely divided active compound. Suitable solid carriers are lactose, pectin, dicalcium phosphate, microcrystalline cellulose, sucrose, kaolin, dextrin, gelatin, starch, tragacanth, low melting wax, coca butter and the like. Liquid preparations include solutions, suspensions and emulsions, e.g. solutions of compound of formula I in water or water-propylene glycol mixture for parenteral injection. Liquid preparations can also be formulated along with non-ionic surfactants and edible oils such as corn, peanut and sesame oils. Aqueous solutions for oral use can be prepared by dissolving the active component in water and adding suitable colorants, flavours stabilizing and thickening 46 agents, as required. Aqueous suspension for oral use can be made by dispersing the finely divided active component in water with a viscous material, e.g. natural or synthetic gums, resins, methyl cellulose, sodium carboxymethyl cellulose and othe known suspending agents. The adjuvants may also include preserving agents and anti-oxidants. Compositions for topical application may take the form of liquids or gels, containing a therapeutically effective concentration of compound of formula I admixed with a dermatologically acceptable carrier. The pharmaceutical preparations may be in unit dosage form. In such form, the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage can be in the form of tablets, capsules, powdersin vials or ampoules, ointments, gels, creams or any other form. The quantity or concentration of the active compound in such unit dose preparations may be varied or adjusted according to the particular application and potency of the active ingredient. 47 A compound of formula (I) and its pharmaceutical^ acceptable salts wherein, A is either hydrogen or fluorine, B is either hydrogen or fluorine, A and B together is hydrogen and fluorine, Ri is a group of formula, wherein, Q is either an alkyl group of two carbon atoms, an alkene group of two carbon atoms or an alkyne group of two carbon atoms Y is oxygen, sulfur or an amino function of formula NR3 wherein, R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or branched; cycloalkyl of 3-7 carbon atoms; CHO, -COOH, -COOR,; COCR,; CN; aryl or heteroaryl wherein, Rt is an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms. Ar is a substituted phenyl ring or a substituted pyridine ring of formula —O-R3 or Ar is a five membered ring of formula 48 or Ar is a fused bicyclic phenyl or pyridine ring of formula wherein, M is either CH or N Z is CH, NH, O, or S, X is a group selected from OR,, NR4R5, N02, SR,, SOOR,, SOONR4R5, F, CI, Br or I, wherein R4 is as defined hereinbefore, and and R3 is as defined hereinbefore R5 is hydrogen or R4 R2 is selected from the groups shown below, and the corresponding N-oxides thereof. A compound according to Claim 1 wherein in said compound of formula I Aryl is phenyl substituted with (0) or (1) of F, CI, "OCH3, "OH, "NH2, CrC4 alkyl, 0-C(0)-OCH3," N02or"CN. 49 3. A compound according to Claim 1 wherein said compound of formula I is selected from the group consisting of: 1) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 2) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 3) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 4) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide. 5) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 6) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 7) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide. 8) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 9) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 10) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 11) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide. 12) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide. 13)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 14) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide. 15) (S) - N -[ [ 3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide. 16) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl 1 methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide. 17) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 50 18) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 19) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl]-4-oxo-4-(2-thienyl)butanamide. 20) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 21)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide. 22) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 23) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 24) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 25) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 26) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) — 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 27) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 28) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide. 29) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide. 30) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide. 31)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (2 - thienyl)butanamide - N - oxide. 32) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide. 33) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N -oxide. 34) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 51 35) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4- oxobutanamide. 36) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4- oxobutanamide. 37) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4- oxobutanamide. 38) (S) - N -[ [ 3 - (3 - fluoro - 4 - benztriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 39) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 40) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 41) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4 - oxobutanamide. 42) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 43) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 44) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide. 45) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 46) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 47) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide. 48) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide. 49) (S) - N .-[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 50) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 51) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 52) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide. 52 53) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 54) (S) -N-[[3-(3- fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 55) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 56) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -■ ( 4 - thiomethylphenyl )butanamide. 57) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2 - naplrthyl) - 4 - oxobutanamide. 58) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide. 59) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 60) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 61)(S)-N-[[3-(3- fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 62) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 63) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 64) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide. 65) (S) - N -[ [ 3 - ( 5 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 66) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (4 - thiomethylphenyl)butanamide. 67) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 68) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 69) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide. 70) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 53 71) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 72) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 73) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 74) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 75) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 76) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) --2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2 - naphthyl) - 4 - oxobutanamide. 77) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - '2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 78) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide. - ' 4. A compound as claimed in claim 3 wherein said compound of formula I is selected from the group of N-oxide of the said compounds 1 to 78. 5. A pharmaceutical composition comprising a) atleast one of I) any compound of claims 1 to 4 and II) its pharmaceutically acceptable salts and b) a pharmaceutically acceptable carrier. 6. A pharmaceutical composition according to claim 5 comprising a solid or liquid preparation. 7. A pharmaceutical composition as claimed in anyone of claims 5 to 6 for oral or parenteral administration. 8. A method of preparation of the compound of formula I and/or its pharmaceutically acceptable salts comprising: coupling of the amino fragment of compound of formula II 5^ (II) with a carboxylic acid of formula III in the presence of an acid activating group or a dehydrating agent in a suitable solvent. (Ill) wherein R2 has the same meaning as given in claim 1. 9. A method as claimed in claim 8 wherein the compound of formula II is preferably selected from (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine,(S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, S) - N -[3 - (3 - fluoro - A - benzotriazolylphenyl) - 2 - oxo - 5 -oxazolidinyl] methyl amine, and (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine. 10. A method as claimed in anyone of claims 8 or 9 wherein the compound of formula III is selected from 4-(2-Naphthyl)-4-oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic acid, 4-oxo-4-(2' methy lpropyl)phenylbutanoic acid, 4-Oxo-4-(2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 - 5S oxobutanoic acid,4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, . 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 - phenyl - but - 2 - ynoic acid. 11. A compound of formula I, its pharmaceutically acceptable salts and pharmaceutical compositions obtained thereof substantially as herein described and illustrated. Dated this 5th day of March 2005 Dr. Sanchita Ganguli Of S. MAJUMDAR & CO. Applicants' Agent 5t F0RM2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See section 10; rule 13) 1. Title of the invention. - OXAZOLIDINONE DERIVATIVES, PROCESS FOR THEIR PREPARATION AND THEIR USE AS ANTIMYCOBACTERIAL AGENTS 2. Applicants) (a) NAME : LUPIN LIMITED (b) NATIONALITY : An Indian Company (c) ADDRESS : 159, C.S.T. Road, Kalina, Santacruz (East), Mumbai - 400 098, Maharashtra, India 3. PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed FIELD OF THE INVENTION The present invention relates to novel compounds belonging to the class of oxazolidinones useful in the treatment of acid fast organisms such as Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium spp. The present invention further relates to methods for preparation of the novel compounds and to pharmaceutical compositions containing the novel compounds useful in the treatment of tuberculosis. BACKGROUND OF THE INVENTION Tuberculosis (TB), an infectious disease caused by the bacterium Mycobacterium tuberculosis is transmitted mainly through air, affecting most often the lungs. When persons with pulmonary TB cough they produce tiny droplet nuclei containing M. tuberculosis, which remain suspended in air for a prolonged period of time. A person who breathes the air containing the aforesaid droplet nuclei containing M. tuberculosis can become infected with TB. TB, one of the three major infectious diseases in the priority list of the World Health Organization's (WHO) agenda kills about two million people around the world every year. About six million new cases are reported every year and nearly 20% of adult deaths and 6% of infant deaths are attributable to the disease (C. Dye et. al., J. Am. Med. Ass., 1999, 282, 677-686). About a billion people are expected to be affected by TB by the year 2020, with 35 million likely to succumb to the disease (WHO Fact Sheet No. 104, Global Alliance for TB Drug Development- Executive Summary of the Scientific Blueprint for TB Development : http://www.who.int/inf-fs/en/factl04.html). With the emergence of the AIDS epidemic and the increase in cases of HIV coupled with TB as well as the continued resistance of M. tuberculosis to isoniazid and rifampicin, the two most powerful anti-tubercular drugs available today there is an urgent need for new anti-tubercular drugs to combat the killer disease (S. H. E. Kaufmann et. al., Trends Microbiol., 1993, 1,2-5 ; B. R. Bloom et. al., N. Engl. J. Med., 1998, 338, 677-678). Although, many new compounds are becoming available for fighting a number of infectious diseases, the number of such compounds having antimycobacterial activity are few. This could partly be due to the complexity of research involved and partly due to business considerations (B. N. Roy et. al., J. Ind. Chem. Soc, April 2002, 79, 320-335 and references cited therein). However, renewed thrust in research in the last decade has resulted in development of new antimycobacterial compounds, a) differing widely in structures, b) having different mode/mechanism of action, c) possessing favourable pharmacokinetic properties, d) which are safe and have low incidence of side-effects, and e) which provide a cost-effective dosage regimen. 2 Among the aforesaid new compounds, the oxazolidinones first developed during the mid-1980s (W. A. Gregory et. al., J. Med. Chem., 1989, 32,1673-1681 and 1990,33,2569-2578 ; C-H Park et. al., J. Med. Chem., 1992, 35, 1156-1165) are a unique class in themselves. The in vivo results for some of the oxazolidinones show that they are active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, including resistant strains such as methicillin-resistant Staphylococcus aureus [MRSA], methicillin-resistant Streptococcus epidermidis [MRSE], penicillin-resistant Streptococcus pneumoniae [PRSP], vancomycin-resistant enterococci [VRE], etc. (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999,9 (5), 625-633 and the references contained therein). The oxazolidinones inhibit bacterial protein synthesis at a very early step in the initiation of complex formation involved in the process of translating mRNA into protein. The oxazolidinones, in general, are not cross-resistant with any known antibiotic because of this unique mechanism (D. C. Eustice et. al., Antimicrob. Agents Chemother., 1988, 32, 1218 and Biochem. Biophys. Res. Commun., 1988,150. 965). A feature of the oxazolidinone molecule is that only those compounds, which are enantiomers with a (5S)-acetamidomethyl configuration in the left side of the molecule are known to exhibit antibacterial activity (W. A. Gregory et. al., J. Med. Chem., 1989, 32, 1673-1681). Another feature is that most of such antibacterial compounds invariably carry a (substituted) phenyl ring attached to the nitrogen atom of the oxazolidinone ring in the right side of the molecule (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999, 9 (5), 625-633 and the references contained therein). The most promising compound among the N-phenyl oxazolidinones, which has been approved for human use is (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidin-yl]methyl]-acetamide), commonly known as linezolid (M. Barbachyn et. al., WO 995/07271). Linezolid possesses good in vitro and in vivo potency against most of the Gram-positive bacteria, including resistant strains {Drugs of the Future, 1996,21.(11), 1116-1123). The left hand side i. e. position 5- and the right hand side i. e. position 3- respectively of the oxazolidinone ring nucleus allows for many variations and has resulted in the discovery of a large number of compounds having antimicrobial and antibacterial properties. Such representative compounds, albeit not meant to be limiting are disclosed in the following prior art references. These are: i) US 4,942,183 (Gregory et. al.) and US 4,948,801 (Carlson et. al.) collectively disclose certain 3-substituted phenyl- 5-aminomethyl oxazolidinones, possessing useful antibacterial activity, ii) US 5,529,998 (Habich et. al.) discloses certain 3-benzoxazoyl- and benzothiazolyl-5- acetyl amino methyl oxazolidinones, useful as antibacterial medicaments. 3 iii) US 5,565,571, US 5,654,428, US 5,756,732, US 5,801,246 and US 5,929,248 (Barbachyn et. al.) collectively disclose several substituted aryl and heteroaryl phenyloxazolidinones carrying an acetyl aminomethyl function at the 5-position, specifically oxazolidinones having an aryl or heteroaryl group at the para position of the 3-phenyl ring and additional substituents at the meta positions of the 3-phenyl ring, which are useful as antibacterials. iv) US 5,652,238 (Brickner et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a hydroxyl acetyl piperazine moiety, active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, as well as anerobic organisms such as bacteroides and Clostridia species as well as acid-fast organisms such as Mycobacterium tuberculosis. v) US 5,684,023 (Riedl et. al.) discloses certain 3- benzofuranyl- and benzothienyl oxazolidinones, carrying an azido, hydroxy or acetyl aminomethyl group at the 5-position, useful as antibacterial medicaments. vi) US 5,688,792 (Barbachyn et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a (substituted)-morpholine. Such compounds are useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp. vii) US 5,719,154 (Tucker et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the said substitution being a pyrimidinyl or pyradazinyl group. Such compounds are useful as antimicrobial agents. viii) US 5,736,545 (Gadwood et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a five membered heterocycle ring, in particular an azolyl ring. Such compounds are useful in the treatment of microbial infections. ix) US 5,792,765 (Riedl. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-substituted phenyloxazolidinones, the substitution being a heterocyclic moiety, useful as antibacterial medicaments. x) US 5,861,413 (Habich et. al.) discloses certain 2-oxo and 2-thio-l,2-dihydroxyqoinolinyl-1-oxazolidinones, useful as antibacterial medicaments. xi) US 5,880,118 (Barbachyn et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a 4 substituted thiomorholine moiety i. e. oxazine and thiazine derivatives, useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp. xii) US 5,910,504 and US 6,124,334 (Hutchinson et. al.) collectively disclose certain substituted 5-acetyl aminomethyl-3- phenyloxazolidinones substituted at the para position of the 3-phenyl ring with a heteroaromatic moiety, which is five membered having one to four nitrogen atoms or alternatively, a benzoannulated five-membered heteroaromatic ring having one to four nitrogen atoms, useful as antibacterials. xiii) US 6,069,160 (Stolle et. al.) discloses certain substituted 5-acetyl aminomethyl-3-benzocyclopentaneoxazolidinones, containing an heteroatom, useful as antibacterial medicaments. xiv) US 6,227,868 Bl and US 6,410,728 (Sciotti et. al.) collectively disclose certain 5-acetyl aminomethyl-3-phenyloxazolidinones carrying an acetylenic moiety on the 3-phenyl ring, useful for treating bacterial infections, psoriasis, arthritis and toxicity due to chemotherapy. xv) WO 93/23384 (Hutchinson et. al.) discloses certain substituted 5-acetyl aminomethyl-3 -phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, useful for treatment of microbial infections caused by staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium. xvi) WO 97/10223 (Gadwood et. al.) discloses certain substituted 5-acetyl aminomethyl-3-aminoaryl oxazolidinone N-oxide compounds, which are exceedingly water soluble and useful in preparation of pharmaceutical compositions for combating a number of human and veterinary pathogens, staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium, Mycobacterium spp. and Mycoplasma spp. xvii) WO 98/01446 and WO 98/01447 (Betts et. al.) collectively disclose certain substituted 5-acetyl aminomethyl3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a six-membered heteroaryl ring containing two or three ring nitrogen atoms as the only ring heteroatoms, useful as antibacterial agents. xviii) WO 99/02525 (Thomasco et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted by a thiadiazolyl or oxadiazolyl moiety, useful as 5 antimicrobial agents, effective against a number of human and veterinary pathogens, including Gram-positive and Gram-negative aerobic bacteria. xix) WO 99/37630 (Gordeev et. al.) discloses oxazolidinone combinatorial libraries, compositionscontaining the same and methods of preparation thereof involving solid phase synthesis, which provides the said compounds for high-throughput screening. xx) W099/37641 (Bartel. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-bicyclene-substituted oxazolidinones, useful as antibacterial medicaments. xxi) WO 01/09107 (Gordeev et. al.) discloses certain 3-heteroaryl-5-acetyl aminomethyl oxazolidinones, substituted by a thioacyl, aminocarbonyl, alkoxycarbonyl, aminothiocarbonyl, alkoxythiocarbonyl and alkylthiocarbonyl group, useful in treating or preventing an infectious disorder in humans or animals. xxii) WO 01/42242 (Paget et. al.) discloses certain substituted 5-acetyl aminomethyl 3-substituted phenyloxazolidinones, the substitution being a bicyclic heterocyclic system, useful as antibacterial agents. xxiii) WO 02/06278 (Mehta et. al) discloses certain substituted 3-phenyl oxazolidinones and to process for synthesis of the same, the said compounds useful as antibacterial agents, effective against a large number of human and veterinary pathogens, including Gram-positive bacteria and acid fast organisms such as Mycobacterium tuberculosis. xxiv) WO 02/20515 (Madar et. al.) discloses heterocyclic phenyloxazolidinones, useful for treating bacterial infections. However, only a few of the disclosures described hereinbefore provide compounds that can be used as antimycobacterials, while most of the others are silent about the antimycobacterial activity of the disclosed compounds. A need, therefore, exists for new compounds possessing potent antimycobacterial properties for treatment of TB, which as mentioned hereinearlier is assuming alarming proportions. OBJECTS OF THE INVENTION It is thus the basic object of the present invention to synthesize, identify and provide new compounds belonging to the class of oxazolidinones, possessing potent antimycobacterial properties especially for treatment of acid fast organisms such as Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M. kansai. Another object is directed to providing antimycobacterial pharmaceutical composition effective in inhibiting/treating the generation of mycobacterial conditions/cells including Mycotacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M fortuitum and Mkansai. 6 Yet another object is directed to providing a method of treating/inhibiting mycobacterial cells/conditions involving the administrations of effective amount of the novel antimycobacterial compound and/or its salts /composition of the invention. SUMMARY OF THE INVENTION Thus according to the basic aspect of the present invention there is provided compound of formula (I) and its pharmaceutically acceptable salts thereof wherein, A, B = H, and/or F Ri is a group of formula wherein, Q is CH2-CH2, CH=CH, or C=C Y is O,S or NR3 wherein, R3 is Ci - C4 alkyl (straight, branched, unsaturated), cycloalkyl, COOH, COOR,, CHO, COCR4, CN, aryl, heteroaryl wherein, R is an alkane of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms, and Ar is an aromatic carbocycle represented by 7 wherein, X is OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, Br, CI, F, or I, M is-CHorN,and Zis-CH,-NH,OorS and wherein, R3 and R4 are as described hereinbefore, and R5 is H, or same as R4, and R.2 is selected from the groups shown below, and the corressponding N-oxides thereof Heteroaryl or Heterocycloalkyl wherein K is O, S, SO, S02, or CH2 According to another aspect of the invention there is provided a pharmaceutical composition comprising: i) atleast one of an antimycobacterially effective amounts of compound of formula I and pharmaceutically acceptable salts there of; and ii) a pharmaceutically acceptable carrier. According to yet another aspect of the present invention there is provided a method of inhibiting growth of mycobacterial cells such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M.kansai.,comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof. 8 According to yet another aspect of the present invention there is provided a method of treating mycobacterial conditions such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M kansai, comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof. According to another aspect, there is provided a process for the manufacture of the compound of formula I or its pharmaceutically acceptable salts comprising : coupling the amino fragments of compound of formula II with the carboxylic acid fragment of formula III. The above disclosed compound of formula I its pharmaceutically acceptable salts thereof are found to have antimycobacterial properties and the same in admixture with pharmaceutically active additives, an be administrated orally or paranterally for treatement of mycobacterial conditions especially TB. DETAILED DESCRIPTION OF THE INVENTION In the pharmaceutically active compound of formula (I) of this invention, the definition of the symbols and groups A, B, Rt and R2 are as follows : A is either hydrogen or fluorine, B is either hydrogen or fluorine, A and B together is hydrogen and fluorine, When A is hydrogen, B is fluorine and vice-versa. R1 represents a group of formula, Q is either an alkyl group of two carbon atoms (CH2-CH2), an alkene group of two to carbon atoms (CH=CH), or an alkyne group of two carbon atoms (C=C) 9 Y can either be oxygen, sulfur or an amino function of formula NR3, wherein R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or branched. Suitable alkyl groups are methyl, ethyl, n-propyl, n-butyl, iso-propyl, iso-butyl, tert- butyl, ethylene, propylene, 1, butene, both the geometric isomers of 2-butene i. e.(cis)-2-butene and (trans)-2-butene, and iso-butylene. or R3 is a cycloalkyl group of 3-7 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl, or R3 is a carboxylic acid group (-COOH) or a carboxylic acid ester of formula-COOR4, wherein R4 is H, an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms. R3 is further an aldehyde (-CHO), an acetyl group (-COCR4), wherein R4 is as mentioned hereinbefore or R3 is a nitrile (CN), aryl or heteroaryl, wherein Aryl is phenyl substituted with (0) or (1) of-F, -CI, -OCH3, -OH, -NH2, -CrC4 alkyl, -O-C(O)- OCH3,-N02or-CN,and Heteroaryl or Ar is a five membered ring of formula or Ar is a fused bicyclic phenyl or pyridine ring of formula 10 The group Ar is a substituted phenyl ring or a substituted pyridine ring of formula wherein, M is either CH or N; Z is -CH, -NH, O or S and R3 is as defined hereinbefore, X is a group selected from OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, F, CI, Br or I, wherein R4 is as defined hereinbefore, and R5 is hydrogen or R4. R2 is selected from the groups shown below, and the corresponding N-oxides thereof. Heteroaryl or Heterocycloalkyl wherein K is O, S, SO, S02, or CH2 The preferred novel compounds of formula (I) that form part of this invention, are as follows. The following compounds 1 to 78( named as per IUPAC or CAS nomenclature) are preferred compounds of formula (I) of the invention. 1. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide. 2. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 3. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 4. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide. 5. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 11 6. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide. 7. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide. 8. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 9. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 10. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 11. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methylphenyl) - 4- oxobutanamide. 12. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - (4 - methylphenyl) - 4- oxobutanamide. 13. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 14. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide. 15. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide. 16. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide. 17. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 18. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 19. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide. 20. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - (2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 21. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide. 22. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 23. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 12 24. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazohdinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 25. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazohdinyl methyl] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 26. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazohdinyl ] methyl - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide. 27. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 28. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl - 4 - oxo - 4 -( 2 - thienyl)butanamide. 29. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide. 30. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide. 31. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide. 32. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide. 33. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N - oxide. 34. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 35. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methoxyphenyl) - 4- oxobutanamide. 36. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - chlorophenyl) - 4- oxobutanamide. 37. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2,4 - dimethylphenyl) - 4- oxobutanamide. 38. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benztriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 39. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 40. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 41. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 13 42. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 43. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide. 44. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide. 45. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 46. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 47. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide. 48. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide. 49. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 50. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 51. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 52. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 -( 2 - thienyl)butanamide. 53. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 54. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 55. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - phenylbut - 2- enamide. 56. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo- 4 - ( 4 - thiomethylphenyl )butanamide. 57. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2 - naphthyl) - 4 - oxobutanamide. 58. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide. 59. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 14 60. (S) - N -[ [ 3 - (3 - fluoro—4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 61. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbut - 2- enamide. 62. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 63. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide. 64. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide. 65. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 66. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - (4 - thiomethylphenyl)butanamide. 67. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - ( 2 - naphthyl) - 4 - oxobutanamide. 68. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 69. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide. 70. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 71. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 72. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 73. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 74. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 75. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 76. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 77. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 15 78. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 — oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide. The respective N-oxides of the group R2 of the compounds of formula I listed above also form a novel aspect of the present invention. The pharmaceutically active compounds of formula (I), the corresponding N-oxides of the group R2 and pharmaceutically acceptable salts thereof of this invention can be prepared by methods known to one skilled in the art. Typically, compounds of formula (I), can be prepared by coupling of the amino fragment of formula (II) Scheme-! General method for synthesis of compounds of formula (I) In a typical experiment, the amine compound of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinbefore is dissolved in a 1:1 mixture of tertahydrofuran and water or a 1:1 mixture of methylene chloride and water. To the solution is added the carboxylic acid compound of formula (III), followed by addition of 1-hydroxybenztriazole (HOBt). The resulting mixture is cooled to a temperature of 0-5° C to which l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 1.1 Eq.) is added and gradually allowed to warm to room temperature and agitated at this temperature for 24 hours. At the end of 17 the reaction, a solution of saturated aqueous sodium bicarbonate is added and the organic phase separated from the aqueous phase. Evaporation of the solvent and chromatography of the residue over silica gel affords compound of formula (I), generally as white solids. The N-oxides of the group R2 of compound of formula (I) thus obtained are preferably prepared by addition of m-chloro perbenzoic acid (m-CPBA) to a cooled solution of the compound of formula (I) in a chlorinated hydrocarbon solvent such as methylene chloride and ethylene chloride and thereafter agitating the reaction mixture at room temperature for 12-15 hours. Evaporation of the solvent under reduced pressure, followed by chromatography of the residue over silica gel affords the corresponding N-oxides in high purity. The N-oxides thus prepared, while retaining most of the antimycobacterial activity of the corresponding deoxo compound exhibit exceedingly high water solubility over the deoxo analogue, thereby helping in manufacture of suitable iv formulations, which forms an important aspect of this invention. The starting materials required for synthesis of compound of formula (I), thus involve the amine compound of formula II and the carboxylic acid compound of formula III. The amine compound of formula II can be selected from i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vi) (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, and viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine. 18 The carboxylic acid compound of formula III can be selected from 4-(2-Naphthyl)-4- oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic acid, 4-oxo-4-(2'methylpropyl)phenylbutanoic acid, 4-Oxo-4- (2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 - oxobutanoic acid,4 - (2,4 - dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 - phenyl - but - 2 - ynoic acid. 20 Thus, the starting amines of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinearlier are prepared as per the method disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33, 2569-2578; C. Wang et. al., Tetrahedron, 1989, 45, 1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO 95/25106 and WO 97,21708. The method is essentially summarized in Scheme-II. In a typical method, morpholine, thiomorpholine, piperidine, 4-benzyl piperazine, pyrrolidine, 1,2,4-triazine, 12,3-benzotriazine, benzyl amine, a heterocycloalkyl or a heteroaryl moiety etc., each one of which corresponds to the group R2 defined hereinbefore is reacted with 3,4-difluoro nitrobenzene in the presence of a base and a solvent to give the corresponding derivative in which the fluorine atom at 4-position is substituted by the group R2. The nitro group in the compound thus obtained is reduced to amino group, which is thereafter protected by a suitable protective group. Reaction of the N-protected compound thus obtained with (R)-glycidyl butyrate in the presence of a strong base like n-butyl lithium leads to formation of the 5-hydroxymethyl oxazolidinone ring. The hydroxy group in the compound thus obtained is converted to sulfonyl derivative, for e.g. a methanesulfonyloxy (mesyl) or a p-toluenesulfonyloxy (tosyl) derivative by reaction with methanesulfonyl chloride or p-toluenesulfonyl chloride respectively. Reaction of the respective mesyl or tosyl derivative with sodium azide gives the corresponding azide, which is converted to the amine compound of formula (II) by standard methods, for e.g. by reaction with a triaryl/trialkyl phosphine, followed by hydrolysis. The starting carboxylic acid fragments of formula (III), wherein the group Ar has the same meaning as defined hereinearlier are prepared as per the method disclosed in Org. Reactions, 1949, 5, 229-289; Quart. Rev. Chem. Soc, 1954, 8, 355-379; Chem. Rev., 1955, 55, 229-281, and J. Am. Chem. Soc, 1947, 69, 1784-1786. The method is essentially summarized in Scheme-HI. Scheme-Ill General method for synthesis ofalkane and alkene carboxylic acid s of formula (HI) In a typical method, the aromatic compound Ar-H, wherein Ar is as defined hereinbefore is reacted with succinic anhydride in the presence of a Lewis acid, such as anhydrous aluminium chloride and in the presence of an anhydrous solvent and the mixture heated to 100° C to give the carboxylic acid derivatives of formula (HI), wherein Q is alkyl of 1-4 carbon atoms. 23 Similarly, compounds of formula (III), wherein Q is an alkene (CH=CH) are prepared by reaction of the aromatic compound Ar-H, wherein Ar is as defined hereinbefore with maleic anhydride under the same conditions mentioned hereinbefore. Compounds of formula (III), wherein Q is an alkyne (C=C) are prepared by reaction of propiolic acid ester with an aldehyde of formula Ar-CHO in the presence of butyl lithium and in the presence of an aprotic solvent such as THF at -78° C to give the corresponding secondary alcohol, which is oxidized to the keto derivative using manganese dioxide as the oxidizing agent. Saponification gives the carboxylic acid derivative of formula (ID) [ US 4,929,741 (A. Fischili et. al.) ] The synthesis is summarized in Scheme-IV. P = any protective group The synthesis of compound of formula (I) of this invention and the synthesis of the respective starting material amines of formula (II) and the carboxylic acids of formula (III) are further described herein in detail. SYNTHESIS OF THE STARTING AMINES OF FORMULA OD The amines were prepared as per the chemistry summarized in the Scheme-H and as per the methods disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33,2569-2578; C. Wang et. al., Tetrahedron, 1989, 45,1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO 24 95/25106 and WO 97,21708. Commercially available raw materials and known techniques were utilized for the synthesis. The optically pure amines as such were obtained by using optically active intermediates or resolution of racemic mixtures by a suitable reagent. The preferred enantiomer is (S), at the chiral centre on the oxazolidinone ring. Example 1 General Method for Preparation of the Amines (II) The oxazolidinone azides of general formula (8), given in Scheme-II (1.0 eq) were dissolved in dry THF (10 times by volume ) and treated with triphenyl phosphine (1.5 eq.) at room temp. The resulting solution was stirred for 6hrs at room temp. Water [2 eq. of (8)] was added and the solution heated for 6hrs at 55 - 60° C. The solvent was evaporated and the residue chromatographed on a column of silica gel (100 -200 mesh) and eluted initially with ethyl acetate and then with chloroform : methanol (4:1) to give the the amines (II) as white solids. The following amines i) to viii) of formula I were prepared by this general method, viz. i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vi) (S) - N -[3 - (3 - fluoro — 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, and viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine. SYNTHESIS OF THE STARTING CARBOXYLIC ACIDS OF FORMULA (HP Example 2 4-(2-Naphthyl)-4-oxobutanoic acid Naphthalene (5.0gm, 0.039moles) and succinic anhydride (4.68gm, 0.0468 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (11.44g, 0.0858 moles) was added at 25 room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 25 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid. Subsequent column chromatography gave a buff coloured solid. Subsequent chromatography gave 3.7 gm (41%) the title compound, mp 173-174° C. 'H NMR (CDCI3, 5) : 8.40 (s,lH), 7.7 - 8.0 ( m, 4H), 7.4 - 7.6 (m,2H), 3.33 (t,2H), 2.77 (t,2H + 1H). The filterate was concentrated to give 5.8 gm of a mixture of 4-(2-naphthyl)-4-oxobutanoic and 4-(l-naphthyl)-4-oxobutanoic acid. Example 3 4- Oxo-4-(2- ThienylJbutanoicacid Thiophene (5.0gm, 0.059moles) and succinic anhydride (7.13gm, 0.0713 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (17.43gm, 0.131 moles) was added at room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 30 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (50 ml). The solid was dried at room temp to give 9.8 gm (89%0 of the title compound, mp 103 - 107° C. !H NMR (CDCI3, 8) : 7.69 (dd, 1H), 7.58 (dd, 1H), 7.07 (dd,lH), 3.9 (bs, 1H), 3.23 (t, 2H), 2.74 (t,2H). Example 4 4- Oxo-4-(4-thiomethyl)phenylbutanoic acid Thiophenol methyl ether (8.0gm, 0.0645moles) and succinic anhydride (7.75gm, 0.0774 moles) were taken up in dichloroethane (80 ml). Aluminium chloride (18.90gm, 0.1419 moles) was added at room temperature. The resulting mixture stirred for 0.5hr and then heated at 85° C for lhr. The reaction mixture was cooled to room temperature, diluted with 40 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (80 ml). The solid was dried at room temp to give 6.9 gm (48%) of the title compound, mp 151 -154° C. H NMR (CDCI3, 5) : 7.82 (d,2H), 7.20 (d, 2H), 4.2 (bs, 1H), 3.21 (t, 2H), 2.73(t, 2H),2.45 (s,3H). 26 Example 5 4 - oxo -4- (2'methylpropyl)phenylbutanoic acid 2'methylpropylbenzene (5.0m, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles), were taken up in dichloroethane (50 ml). Aluminium chloride (10.90g, 0.0821 moles ) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 ml of a 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.7 gm (99%) of the title compound as a solid, mp 102 - 105° C. !H - NMR (CDC13, 8) : 7.83 (d,2H), 7.17(d,2H), 3.24(t,2H), 2.74(t, 2H), 2.46 (d, 2H), 1.80 (pent., 1H). Example 6 4 - Oxo - 4 - (2',2'dimethylethyl)phenylbutanoic acid 2',2'dimethylethylbenzene (5.0gm, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (10.90gm, 0.0821 moles) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 m of a 1:1 mixture of water Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.5 gm (97%) of the title compound as a solid, mp 103 — 107° C. !H-NMR (CDCI3,8) : 7.94(d,2H), 7.50 (d, 2H), 3.29 (t,2H), 2.82 (t,2H), 1.36 (s,9H). Example 7 Using the appropriate aromatic compound (Ar-H) and succinic anhydride and following exactly the method described in Examples 2-6 the following carboxylic acids can be prepared, viz. i) 4 -(4 -methylphenyl)- 4 - oxobutanoic acid, ii) 4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid, iii) 4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid, iv) 4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, v) 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, vi) 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid, vii) 4 -{2- Naphthyl)- 4 - oxobutanoic acid, viii) 4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, ix) (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and x) 4 - oxo - 4 - phenyl - but - 2 - ynoic acid. 27 SYNTHESIS OF THE COMPOUNDS OF FORMULA (D Example 7 Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - J - oxazolidinyl ] methyl] — 4-(4- naphthyl) -4- oxobutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 dichloromethane-water mixture (10 ml). To this was added 4 -( 2 - naphthyl- 4 - oxobutanoic acid (0.154gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) the resulting mixture was cooled to 0° C. l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added the resulting mixture was allowed to warm to room temperature and then stirred for 24hr. Saturated aqueous sodium bicarbonate solution (2ml) was added to the reaction mixture, stirred for 15 min and then the organic layer separated and the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.22 gm, 64%) as a white solid. MS (M+l) = 506 m/z H NMR (CDC13, 5) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, 1H ), 7.01(dd,lH ), 6.74 (t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, 1H), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91 (m,4H), 2.60(t, 2H). Example 8 Preparation of (S) -N-[[3- (3-fluoro-4-morpholinylphenyl) -2-oxo-5- oxazolidinyl ] methyl] -4- oxo -4-(2- thienyl)butanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml) . To this was added 4 - oxo - 4 (2 - thienyl)butanoic acid (0.125gm, 0. 00068 moles) and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the resulting mixture was allowed to warm to room temp and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated sodium bicarbonate was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separatedand the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.175 gm, 56%) as a white solid MS (M+1) = 462 m/z 28 lH NMR (CDC13, 8) : 7.63(d,lH ), 7.55 (dd,lH ), 7.35(dd,lH), 7.04(t, like dd, 2H), 6.83(t,lH), 6.30 (t,lH), 4.69(m,lH), 3.93 (t, 1H), 3.6- 3.8 (m, 3H),3.80 (m,4H), 3.61(dd, 2H), 3.21(dd,2H),2.97 (m,4H),2.55(t, 2H). Example 9 Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( V- methyl - 4 - propylphenyl) - 4 - oxobutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 -oxo - 5 -oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml). To this was added 4 - [ 4(2'-methylpropylphenyl)]- 4 - oxobutanoic acid (0.158gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated, and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.210gm, 60%) as a white solid. MS(M=l) = 512m/z 'H NMR (CDC13, 8) : 7.73(d,2H ), 7.52 (dd,lH ), 7.28(m,lH ),7.15(d,2H ), 7.05 (d,lH), 6.39 (t,lH), 4.75(m,lH), 3.91 (m, 4H), 3.5- 3.9 (m, 4H), 3.28 (dd, 2H), 3.16 (m,4H),2.54 (t, 2H), 2.45 (d, 2H), 1.82 (pent., 1H), 2.60 (t, 2H). Example 10 Preparation of(S) -N-[ [3 - (3 -fluoro -4- morpholinylphenyl) - 2 -oxo - J - oxazolidinyl J methyl J -4- oxo - 4 -(4- thiomethyl) phenylbutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF -water mixture (20 ml). To this was added 4 - (4-methlythiophenyl) - 4 - oxobutanoic acid (0.152g, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) and the resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142g, 0.00074 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate was added to, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The 29 combined fractions were concentrated to give the title compound (0.270 gm, 79%) as a white solid. MS (M+l) = 502 m/z JH NMR (CDC13, 5) : 7.70(d,2H ), 7.37 (dd,lH ), 7.14(d,2H ), 7.00 (dd,lH), 6.79(t,lH), 6.38 (t,lH), 4.71(m,lH), 3.86(t,lH),3.5- 3.9 (m, 4H), 3.81 (m, 4H), 3.22 (dd, 2H), 2.96 (m,4H),2.53 (t, 2H), 2.45(s,3H). Example 11 Preparation of:. (S) - N-[[3 - (3 -fluoro -4- morphottnylphenyl) — 2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) - 4 - oxobutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.100gm, 0.00034 moles) was taken up in 1:1 THF-water mixture (20 ml) . To this was added 4 - (4- chlorophenyl) - 4 - oxobutanoic acid(0.072g, 0.00034 moles and HOBt (0.046g, 0.00034 moles) .The resulting mixture was cooled to 0°C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.071gm, 0.00037 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated and 2 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with dichloromethane. The organic layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give (0.070gm, 42%) of the title compound as a white solid. MS (M+l) = 490 m/z JH NMR (CDCI3, 8) : 7.72(d,2H ),7.37 (dd,lH ),7.31(d,2H ), 6.98 (dd,lH),6.79 (t,lH), 6.28 (t,lH), 4.69(m,lH), 3.83 (t, 1H), 3.81 (m, 4H), 3.4- 3.m (m, 3H), 3.21 (dd, 2H), 2.97 (m,4H),2.54 (t,2H). Example 12 Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 -naphthyl) - 4 - oxobutanamide - N - oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (2 -naphthyl) - 4 - oxobutanamide (0.950gm, 0.0019 moles) in dichloromethane (150 ml) was added 60% m -CPBA (0.550g, 0.0032 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The column was eluted with ethyl acetate (200 ml), followed by a mixture of chloroform : methanol 30 (4:1,600 ml).Concentration the combined fractions gave the title N-oxide (0.891g, 82% ) as a white solid. !H NMR (CDCI3, 8) : 8.59(t,lH ), 8.36(s,lH),7.7-7.9 (m,5H), 7.2 -7.5 (m,2H),7.08 (dd,lH), 6.60(t,lH), 4.76(m,lH), 4.61(bt,2H), 3.5 - 4.3 (m, 9H), 3.42 (dd, 2H), 2.83 (bdd,2H), 2.61 (bt, 2H). Example 13 Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide. To a cooled solution (0 - 5° C) of (S) - N -[[3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - oxo - 4 - (2 - thienyl)butanamide (0.850gm, 0.0017moles) in dichloromethane (120 ml) was added 60% m -CPBA (0.550g,0.0032 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The column was eluted with ethyl acetate (200ml) followed by a mixture of chloroform : methanol (4:1,600 ml).Concentration of the combined fractions gave the tile N-oxide (0.790g, 90%) as a white solid. 1HNMR( CDCI3,5) : 8.63(t,lH), 7.77(dd,lH), 7.65 (d, 1H), 7.56 (d, 1H), 7.09 (dd, 1H),7.04 (dd,lH), 6.45(t,lH), 4.68(m,lH), 4.65(bt,2H), 4.22 (dt,2H), 3.89(t,lH), 3.5 - 3.9 (m, 5H), 3.22 (dd, 2H), 3.00 (bd,2H), 2.54 (t, 2H). Example 14 Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) -4- oxobutanamide -N- oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide, (1.150gm, 0.0023 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.725gm, 0.0040 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1,600 ml). Concentration of the combined fractions gave the title N-oxide (0.950g, 80%) as a white solid. 'HNMRtCDCk 8) : 8.61(t,lH ), 7.76(d,2H), 7.72 (dd, 1H), 7.34 (d, 2H), 7.10 (dd, 1H), 6.46(t,lH), 4.70(m,lH), 4.64(bt,2H), 4.16 (dt,2H), 3.94(t,lH), 3.5 - 3.9 (m, 5H), 3.24 (dd, 2H), 2.97 (bd,2H), 2.55 (t, 2H). 31 Example 15 Preparation of(S) -N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo -5-oxazolidinyl ] methyl] -4-/4-(2'- methyl - 4 -propylphenyl) -4 — oxobutanamide -N- oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - [4 - (2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide (1.05gm, 0.0020 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.600gm) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1 , 600 ml). Concentration of the combined fractions gave the title N-oxide (0.891gm, 82%) as a white solid. JH NMR (CDC13, 5) : 8.62(t,lH ), 7.77(dd,lH), 7.75 (d, 2H), 7.14 (d, 2H), 7.12 (dd, 1H), 6.44(t,lH), 4.75(m,lH), 4.64(bt,2H), 4.20 (dt,2H), 3.95(t,lH), 3.91 (t,lH) 3.5-3.9 (m, 4H), 3.26 (dd, 2H), 2.99(bd,2H), 2.57 (t, 2H),2.44(d,2H), 0.83(d,6H). Example 16 Preparation of (S)-N-ff3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4- methylphenyl)-4-thiooxobutanamide To a solution of (S)-n- of (S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4-methylphenyl)-4-oxo-butanamide (0.1 Ogm, 0.00021 moles) in dry THF (5ml) was added Lawessons Reagent (0.052gm, 0.000128 moles) and the resulting solution heated under reflux for 8 hr. The reaction mixture was cooled to room temperature and to this was added saturated aqueous sodium carbonate solution (3ml) and then extracted with ethyl acetate. The solvent was evaporated off and the residue chromatographed over silica gel and eluted with a mixture of ethyl acetate-hexane to give the title compound (0.023 gm, 23%) as a white solid, mp 149-151° C. lH NMR (CDCI3,5) : 8.60 (m, 1H), 7.68 (d, 2H), 7.34 (dd, 1H), 7.14 (d, 2H), 6.96 (dd, 1H), 6.81 (t, 1H), 4.90 (m, 1H), 4.20-4.40 (m, 1H), 3.80-4.0 (m, 4H), 3.50 (m, 2H), 2.90-3.00 (m, 6H). Example 17 Using the appropriate amine compound (II) and the carboxylic acid (HI) and following exactly the method described in Examples 7-16 the following carboxylic acids can be prepared, viz. (S) - N-[ [ 3 - (3-fluoro — 4- morpholinylphenyl) -2- oxo — 5- oxazolidinyl J methyl] — 4-(4- methylphenyl) -4- oxobutanamide. 32 'H NMR (CDCI3, 5) : 7.78 (d, 2H ), 7.44 ( d, IH ), 7.22 ( d,2H ), 7.09 ( d, IH ), 6.88 ( t, IH ), 6.41(t, IH), 4.76 (m, IH ), 3.6 - 4.1 (m, 4H ), 3.86 ( m, 4H ), 3.31 ( dd, 2H ), 2.61 (t, 2H ), 2.40 (s.3H). (S) -N-[[ 3-(3 -fluoro -4 - benzylpiperazinyl) phenyl] -2- oxo - 5 - oxazolidinyl] methy ] -4-oxo -4-phenylbutanamide. lH -NMR (CDC13, 5) : 7-88 ( d,2H ), 7.61 (dd, IH), 7.38 ( m, 5H ), 7.2 - 7.4 (m, 5H), 6.88 (t, IH ), 6.55 (t, IH ), 4.77 ( m, IH), 3.94 (t, IH), 3.5 - 3.7 (m, 3H ), 3.71 ( s, 2H ), 3.34 (dd, 2H ), 3.12 (m, 4H),3.12 (m, 4H ), 2.61 (t, 2H ). (S) - N-f]3 - ( 3 -fluoro - 4 - [methylbenzylamin]phenyl) - 2 - oxo -5 - oxazolidiny] methy ]-4-(4- methyl phenyl) -4- oxobutanamide. H NMR (CDCI3, 8) : 7.90 ( d, 2H ), 7.52 ( dd, IH ), 7.2 - 7.5 ( m, 8H ), 7.05 ( d, IH ), 6.84 (t, IH ), 6.50 (t, IH ), 4.75 (m, IH ), 4.48 (s, 2H ), 3.95 (t, IH), 3.6 - 4.1( m,3H ), 3.64 ( dd, 2H ), 2.71 (s,3H), 2.62 (t,2H). (S)-N-[[3-(3-fluoro-4- benzotriazolylpheny)-2-oxo-5-oxazolidinyl]methy]-4-oxo - 4 -phenylbutanamide. !H NMR ( CDCI3, 5) : 8.16 ( d,lH), 7.84 (d, 2H), 7.66 (t, IH), 7.2 -7.6 (m, 8H), 6.46 (t, IH ), 4.90 (m, IH), 3.98 (t,lH), 3.9 - 4.0 (m, 2H ), 3.65 (m, IH ), 3.39 (ddd, 2H ), 2.65 ( ddd, 2H). (S) -N-[[3-(3-fluoro-4- pyrrolidinylphen) -2-oxo-5- oxazolidinyl]methyl]-4-oxo - 4 -phenylbutanamide. !H NMR (CDCI3, 8) : 7.90 (d,2H ), 7.52 (dd, IH ), 7.44 (d, 2H ), (dd, IH ), 7.04 (dd, IH), 6.65 (t, IH), 6.43 (t, IH), 4.74 (m,lh), 3.93 (t,lH), 3.77 (t,lH), 3.6 3,8 (m, 2H), 3.33 (m, 6H ), 2.63 (t, 3H), 1.94 (m,4H). (S)-N-[[3-(3-fluoro-4- benzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methy]-4-(4- methlyphenyl) - 4- oxobutanamide. !HNMR (CDCU, 8) : 8.16 (d, IH ), 7.3 - 7.9( m,7H), 7.78 (d,2H ), 7.21(d,lH), 6.54(t, IH), 4.89 ( m, IH), 3.8 -42 (m, 3H ), 3.4 - 3.7 (m, 3H ), 2.63 (dd, 2H ), 2.23 (s, 3H ). (S)-N-][3-(3 -fluoro - 4 - thiomorpholinylphenyl) -2 — oxo - 5 - oxazolidinyl] methyl] -4- oxo- 4 -phenylbutanamide. !H NMR (CDCI3, 8) : 7.89 (d, 2H ), 7.39 - 7.60 ( m, 4H ), 7.11 (dd, IH ), 6.90 (t, IH), 6.39 ( t,lH ), 4.76 (m,lH ), 3.94 (t,lH ), 3.80 (t, IH ), 3.6 - 3.7 ( m, 2H ), 3.36 ( dd, 2H ), 3.28 ( m,4H), 2.80 ( m,4H ), 2.62 (t, 2H). (S) — N-[[3 - (3 -fluoro - 4 - benzylpiperazinyl) phenyl] — 2 — oxo — 5 - oxazolidinyl] methyl]- 4-(4- methylphenyl) -4- oxobutanamide. 33 H NMR (CDCI3, 5) : 7.81 ( d, 2H), 7.2 - 7.5 ( m, 8H ), 7.08 (dd, IH ), 6,89 (t, IH ), 6.39 (t, IH ), 4,78 ( m, IH ), 3.95( t, IH), 3.79 (t, IH), 3.6 - 3.7 (ni, 2H ), 3.61(s, 2H), 3.31 ( m,2H), 3.09 (m,4H), 2.65 (m,6H), 2.41 (s, 3H). (S)-N-[[3-(3-fluoro-4- piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl]-4- oxo - 4 - phenylbutanamide. !H NMR (CDCI3, 8) : 7.90(d,2H ),7.60 (dd,lH ),7.45(d,2H ), 7.39 (dd,lH), 7.10 (dd,lH), 6.90 (t,lH), 6.55 (t,lH), 4.78(m,lH), 3.95 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.35 (m, 2H), 3.00 (m,4H0,2.63 (t, 2H), 1.9-1.6 (m,6H). (S)-N-[[3- (3 -fluoro-4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4-(4 - methylphenyl) - 4- oxobutanamide. JH NMR (CDCI3, 5) : 7.79(d,2H ),7.40 (dd,lH ),7.23(d,2H ), 7.09 (dd,lH), 6.91 (t,lH), 6.40 (t,lH), 4.77(m,lH), 3.98 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.30(t, 2H), 2.98 (m,4H), 2.62 (t, 2H),2.41(s,3H), 1.6-1.9 (m,6H). (S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5- oxazolidinyl] methyl]- 4 -(4- methylphenyl) - 4- oxobutanamide. 'H NMR (CDCI3, 8) : 7.80(d,2H ),7.32 (dd,lH ),7.21(d,2H ), 7.01 (dd,lH), 6.60 (t,lH), 6.40 (t,lH), 4.75(m,lH),4.12(m,lH) 3.94 (t, IH), 3.75 (t, IH), 3.4- 3.6 (m, 2H), 3.34 (m, 6H), 2.61 (t, 2H),2.40(s,3H), 1.9(m,4H). (S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4 -(4- methoxyphenyl) -4- oxobutanamide. lU NMR (CDCI3, 8) : 7.79(d,2H ),7.36 (dd,lH ), 7.00 (dd,lH), 6.82 (d,2H), 6.80(t,lH), 6.38 (t,lH), 4.69(m,lH), 3.80 (s, 3H), 3.78 (m, 4H), 3.4- 4.0 (m, 4H), 3.20 (dt, 2H), 2.97 (m,4H),2.55 (dt,2H). (S) -N-[[3-(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4- (2 -naphthyl) -4- oxobutanamide. !H NMR (CDCI3, 8) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, IH ), 7.01(dd,lH ), 6.74 (t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, IH), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91 (m,4H), 2.60(t, 2H). ((S) - N -[[ 3 - (3 -fluoro -4- morpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4- (2, 4-difluorophenyl) -4-oxobutanamide. !H NMR (CDCI3, 8) : 7.73(ddd,2H ), 7.47 (dd,lH ), 7.01(dd,lH ),6.7 - 6.9(m,3H ), 6.30 (t,lH), 4.75(m,lH), 3.89 (m, 4H), 3.5- 3.9 (m, 4H), 3.20 (m, 2H), 3.09(m,4H), 2.52 (t, 2H). (S)-N -[[ 3-(3 -fluoro -4- morpholinylphenyl) -2- oxo -5— oxazolidinyl] methyl] - 4 -[4- (2s',2'- dimethyl- 4 - ethylphenyl) -4- oxobutanamide. 34 !H NMR (CDC13, 8) : 7.75(d,2H ), 7.37 (d,2H ), 7.35(dd,lH ), 7.05 (dd,lH), 6.82(t,lH), 6.37 (t,lH), 4.71(m,lH), 3.5- 3.9 (m, 4H), 3.80 (m, 4H), 3.25 (dt, 2H), 2.97 (m,4H),2.54 (t, 2H), 1.26(s,9H). (S) -N-ff 3 - (3 -fluoro - 4 -fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] -4-(4- methoxyphenyl) -4- oxobutanamide. lU NMR (CDC13, 8) : 7.76(d,2H ), 7.37 (dd,lH ), 7.16(m,5H ), 6.93 (dd,lH), 6.79(d,2H),6.74 ( t,lH), 6.37 (t,lH), 4.66(m,lH),4.14 (s,2H), 3.84(t,lH), 3.74 (s,3H), 3.4- 3.8 (m, 3H), 3.18 (dd, 2H), 2.62(s,3H),2.5 l(t, 2H). (S) -N-ff 3 - (3 -fluoro - 4 - fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl] methy] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide. 'H NMR (CDCU, 8) : 7.77(d,2H ), 7.37 (dd +d,3H ), 7.19 -7.22(m, 3H), 6.98 (dd,lH), 6.77(t,lH), 6.31 (t,lH), 4.69(m,lH), 4.17(s,2H), 3.89(t,lH)„3.72 (dd,lH), 3.5- 3.6 (m, 2H), 3.25 (dd, 2H), 2.64 (s,3H),2.55 (t, 2H), 1.25(s,9H). (S) -N-ff 3 -(3 -fluoro - 4 -[methylbenzylamino]phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] -4- (2,4 - dimethylphenyl) -4- oxobutanamide. lU NMR (CDCI3, 8) : 7.65(d,lH ), 7.46 (dd,lH ), 7.32(m,5H ), 7.04(m,3H), 6.95(t,lH), 6.36 (t,lH), 4.78(m,lH), 4.27(s,2H), 3.97(t,lH),3.6- 3.8 (m, 2H), 3.81 (t, IH), 3.27 (dd, 2H), 2.77 (s,3H),2.61 (t, 2H), 2.44(s,3H), 2.35 (s, 3H). (S)-N -[[ 3-(3 -fluoro -4- tnorpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] - 4 - (2,4 - dimethylphenyl) -4- oxobutanamide. 'H NMR (CDCU, 8) : 7.652(d,lH ), 7.42 (dd,lH ), 7.0- 7.1(m,3H), 6.86(t,lH), 6.38 (t,lH), 4.79(m,lH), 3.95(t,lH),3.5- 3.9 (m, 2H), 3.87 (m, 4H), 3.25(dd, 2H), 3.02 (m,4H), 2.59 (t, 2H), 2.41(s,3H), 2.34 (s, 3H). ^ -N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) —2 — oxo -5 — oxazolidinyl] methyl] — 4 — (2,4 - dimethylphenyl) - 4 - oxobutanamide. JH NMR (CDCI3, 8) : 7.62(d,lH ), 7.31 (dd,lH ), 7.03(s,+dd, 3H ), 6.60(t,lH), 6.36 (t,lH), 4.74(m,lH), 3.94(t,lH), 3.76 (dd, lH),3.67(m, 2H), 3.30 (m, 4H), 3.24 (dt, 2H), 2.60 (t, 2H), 2.44(s,3H), 2.34 (s, 3H).1.94 (m,2H). (S) -N-ff 3-(3-fluoro-4- benztriazolylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4- (2,4- dimethylphenyl) -4-oxobutanamide. !H NMR (CDCI3, 8) : 8.15(d,lH ), 7.80 (dd,lH ), 7.3 -7.7(m,6H ), 7.02(d,2H), 6.39 (t,lH), 4.87(m,lH), 4.07(t,lH), 3.96(t,lH), 3.89 (dq, IH), 3.75(dt,lH), 3.38 (qt, 2H), 2.62 (m, 2H), 2.39(s,3H), 2.26 (s, 3H). (S) - N-ff 3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4- oxo -4-(2- thienyl)butanamide. 35 H NMR (CDC13, 8) : 7.71(d,lH ), 7.63 (d,lH ), 7.31(dd,lH ), 7.11 (t, lH),7.05(dd,lH), 6.68(m,lH), 6.38 (t,lH), 4.74(m,lH), 3.95(t,lH), 3.77 (t, 1H),3.6- 3.7 (m, 2H), 3.36 (m, 4H), 3.28 (t, 2H), 2.63 (t, 2H), 1.96 (m,2H). (S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo - J - oxazolidinyl] methyl] - 4 - oxo -4-(2- thienyl)butanamide. !H NMR (CDC13, 8) : 8.08(d,lH), 7.77(dd,lH ), 7.3 - 7.7(m,7H ), 7.02(t,lH), 6.45 (t,lH), 4.81(m,lH), 4.00(t,lH),3.7- 4.0 (m, 2H), 3.57 (dt, 1H), 3.25 (m, 2H), 2.55 (m,2H). (3? -N-[[3-(3-fluoro-4- morpholinylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4- oxo - 4 -phenylbut - 2- enamide. JH NMR (CDCI3, 8) :7.92 (d,lH), 7.84 (,d,lH), 7.2 - 7.6 (m, 6H), 6.98 - 7.1 (m, 3H), 4.38(m, 1H), 3.5 - 4.1 (m, 4H), 3.84 (m, 4H), 3.03 (m, 4H). (S) -N-[[3-(3 -fluoro-4- piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4-(4 - methoxyphenyl) - 4- oxobutanamide. 'HNMR^MSOde, 8) : 8.25 (t, 1H), 7.79 (d, 2H), 7.38 (dd, 1H), 7.71 (dd, 1H), 6.95 (t,lH), 6.93 (d, 2H + 1H), 4.65 (m,lH), 3.75 (s,3H), 3.99 (t, 1H), 3.64 (dd, 1H), 3.06 (t, 2H), 2.81(m,4H), 1.3 -1.6(m.6H). (S) -N-[[3-(3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4 - chlorophenyl) - 4- oxobutanamide. lH NMR (CDCI3, 8) : 7.73(d,2H ), 7.33 (d,2H ), 7.2 - 7.8 (m, 2H),6.96(dd,lH), 6.34 (t,lH), 4.72(m,lH), 3.84(t,lH), 3.5- 3.8 (m, 3H), 3.21 (dd, 2H), 2.98 (m, 4H),2.54(t,2H), 1.5 - 1.7 (m,6H). (S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl] -4-(2,4 - dimethylphenyl) - 4- oxobutanamide. 'H NMR (CDCI3, 8) : 7.55(d,2H ), 7.4 (m,lH ), 6.9 - 7.0 (m, 3H),6.32(t,lH), 4.70(m,lH), 3.90(t,lH), 3.74 (t,lH), 3.5- 3.7 (m, 2H), 3.20 (dd, 2H), 2.9 - 3.1 (m, 4H),2.52(t,2H), 2.34 ( s,3H), 2.71 (s, 3H ), 1.5 -1.9 (m,6H). (S) - N-[[3 - (3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- methoxyphenyl) -4-oxobutanamide. XH NMR ( CDCI3, 8) : 8.07(d, 1H), 7.2 - 7.8 (m,6H), 7.71(d,2H ), 6.79 (d,2H ), 6.51(t,lH), 4.81(m,lH), 3.4- 4.0 (m, 4H), 3.71 (s, 3H), 3.15 (qt, 2H), 2.52 (dd, 2H). (S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- chlorophenyl) -4-oxobutanamide. 'H NMR (CDCI3, 8) : 8.09(d, 1H), 7.2 - 7.8 (m,6H), 7.75(d,2H ), 7.35 (d,2H ), 6.29(t,lH), 4.81(m,lH), 3.7 - 4.0(m, 3H), 3.5 - 3.7 (bt, 1H),3.25 (qt, 2H), 2.55 (t, 2H). (S)-N-[[3-(3-fluoro-4-(1,2,4-triazolyl)phenyl)-2-oxo-5- oxazolidinyljmethyl] -4- oxo — 4 - phenylbutanamide. 36 H NMR (CDCI3, 8) : 8.62 (bs, 1H ), 8.10 ( s, 1H ), 7.7 -7.8 ( m, 2H ),, 7.67 (dd, 2H, ), 7.44 (t, 1H ), 7.2 - 7.4 (m,3H ), 6.49 (t, 1H ), 4.78 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55 (dt, 1H ), 3.30 (ddd, 2H), 2.54 (dd, 2H). (S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4- methylphenyl) -4- oxobutanamide. XHNMR (CDC13, 8) : 8.71 (bs, 1H ), 8.10 ( s, 1H), 7.7 -7.9 ( m, 4H ), 7.30 (d, 1H, ), 7.21 (d, 2H ), 6.63 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.64(dt, 1H ), 3.35 (qdd, 2H), 2.5 - 2.6 (m, 2H), 2.35( s,3H). (S) - N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] - 4-(4- methoxyphenyl) -4- oxobutanamide. 'H NMR (CDCI3, 8) : 8.68 (bs, 1H ), 8.16 ( s, 1H ), 7.7 -7.9 ( m, 2H ), 7.79( d, 2H ) 7.28 (dd, 1H), 6.85 ( d,2H), 6.58 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.82(s,3H), 3.61(dt, 1H ), 3.32 (qdd, 2H), 2.65 (ddd, 2H). (S) -N-][3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl] -4-(2,4- dimethylphenyl) -4- oxobutanamide. !HNMR (CDCI3,8) : 8.69 (bs, 1H ), 8.17 ( s, 1H ), 7.78( t,lH), 7.75 ( d,lH ), 7.60 (d,lH),7.25(d, 1H, ), 7.10 (d, 1H ),6.99(s, 1H ), 6.54( t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.65(dt, 1H ), 3.25 (qt, 2H), 2.59 (dt, 2H), 2.38( s,3H), 2.29 (s,3H). (S) -N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4- oxo- 4 -(4 - thiomethylphenyl)butanamide. 'H NMR (CDCI3, 8) : 8.57 (bs, 1H ), 8.06 ( s, 1H ), 7.77 (m,2H), 7.61 (d, 2H), 7.19 ( d, 1H ), 7.10 (d, 2H, ), 6.47 (t, 1H ), 4.76 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25 (qdd, 2H), 2.55 (dq,2H),2.39(s,3H). (S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide. lU NMR (CDCI3, 8) : 8.58 (bs, 1H ), 8.06 ( s, 1H ), 7.80(t,lH),7.6 -7.8 ( m, 1H ), 7.67 (d, 2H,),7.32(d,2H), 7.26 (d, 1H ), 6.43 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25 (qt, 2H), 2.53(dt, 2H), 1.22( s,9H). (S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(2'- methyl - 4 - propylphenyl) -4- oxobutanamide. 'H NMR (CDCI3, 8) : 8.61 (bs, 1H ), 8.09 ( s, 1H ), 7.6 -7.8 ( m, 4H ), 7.24 (dd, 1H, ), 7.07 (d, 2H ), 6.38 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.54(dt, 1H ), 3.28(qt, 2H), 2.54(dt, 2H), 2.40( d,2H), 1.77 (pent.,lH), 0.81 (d,6H). (S) - N-[[ 3-(3 -fluoro -4- (1,2,4 — triazolyl) phenyl) -2- oxo -5— oxazolidinyl] methyl] -4-oxo - 4- (2- thienyl)butanamide. 37 'HNMR (CDCI3, 8) : 8.57 (bs, IH ), 8.05 ( s, IH ), 7.76 (t,lH),7.60(dd,lH), 7.53 (dd,lH), 7.25 (dd, IH, ), 7.01 (d, 2H ), 6.47( t, IH ), 4.78 ( m, IH), 3.7 - 4.0 (m, 3H), 3.56(ddd, IH ), 3.25 (qt, 2H), 2.54 (dt, 2H). (S) -N-[[3 -(3 -fluoro -4- (1,2,4-triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl]- 4 - (2-naphthyl) -4- oxobutanamide. !H NMR (CDCI3, 8) : 8.41 (s, IH ), 8.27( s, IH ), 8.02(s,lH), 7.3 -7.9 ( m,6H ), 7.3 - 7.6 (m, 3H), 6.44 (t, IH ), 4.77 ( m, IH), 3.7 - 4.0 (m, 3H), 3.2- 3.7 (m, 3H), 2.5-2.6 (m, 2H). (S) - N-[[3 - (3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4- chlorophenyl) -4- oxobutanamide. lH NMR (CDCI3, 8) : 8.58 (bs, IH ), 8.07 ( s, IH ), 7.6 -7.9 ( m, 2H ), 7.68 (d, 2H), 7.29 (d, 2H,), 7.2 - 7.3 (m, IH ), 6.31 (t, IH ), 4.81 ( m, IH), 3.7 - 4.1 (m, 3H), 3.55(dt, IH ), 3.25 (qt, 2H), 2.55(dt, 2H). (S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4- oxo -4-(2- thienyl)butanamide. H NMR (CDCI3, 8) : 7..5 - 7.7 ( m, 2H), 7.3 - 7.5 (m,lH), 6.8 - 7.3(m,3H ), 6.35(t,lH), 4.69(m,lH), 3.89 (t,lH), 3.76(t,lH),3.59(m,2H), 3.21(dd,2H),3.02 (m, 4H), 2.55 (t, 2H), 1.5 - 1.8 (m,6H). (S) -N-[[3 -(3-fluoro -4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4- (2'- methyl -4- propylphenyl) -4- oxobutanamide. 'H NMR (GDCI3,8) : 8.08 (m, IH ), 7.74 (d, 2H), 7.4 - 7.8 (m, IH ), 7.16 (d, 2H,), 6.97(dd,lH) 6.37 (t, IH ), 4.74 ( m, IH), 3.88 (t, IH), 3.80(t,lH), 3.4 - 3.71 (m, 2H), 3.40(m,4H) 3.25(dd, 2H ), 2.45(d, 2H), 1.80 (pent, IH), 1.5-1.8(m,6H),0.83(d,6H). (S)-N-[[3-(3-fluoro-4-piperidylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(4 - acetamidophenyl) -4- oxobutanamide. 'H NMR (DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.78 (d, 2H), 7.60 ( d, 2H), 7.36 (dd, IH), 7.06 (dd, IH), 6.93 (t,lH), 4.63 (m, IH), 3.95(t,lH), 3.61 (dd,lH), 3.07(dd,lH), 2.81 (m,4H), 1.99 (s, 3H), 1.55 (m, 4H), 1.44 (m, 2H). (S) - N-ff 3 -( 3 -fluoro - 4 * piperidylphenyl) - 2 - oxo - J - oxazolidinyl] methyl] -4- oxo - 4 -phenylbut - 2- enamide. JHNMR (CDCI3, 8) .-7.7-8.0 (m,3H), 7.2 - 7.6 (m, 5H), 7.01 (d,2H), 6.98 (t, IH), 4.80(m, IH), 4.01(t,lH), 3.85(t,lH), 3.77 (t, 2H), 3.16 (m, 4H), 1.5 - 1.9 (m,6H). (S) - N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] ~4- oxo- 4-(4- thiomethylphenyl)butanamide. lU NMR (CDCI3, 8) :7.70 (d,2H), 7.60 (bd,lH), 7.0 - 7.3 (m, 3H), 6.91 (d,lH), 6.47 (t, IH), 4.71(m, IH), 3.87(t,lH), 3.4 - 3.8 (m,3H ), 3.45(m, 4H) 3.21 (dd, 2H), 2.54 (t, 2H), 2.45 (s,3H), 2.06(m,4H). 38 (S)-N-[[3-(3-fluoro-4-pyrrolidinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(2-naphthyl) -4- oxobutanamide. !H NMR (CDC13, 8) : 8.35 (s, IH ), 7.5 - 8.1 (m, 8H ), 6.91(d,lH) 6.53 (t, IH ), 4.72 ( m, IH), 3.38 (m, 4H), 3.2 - 4.0 (m, 6H), 2.61(m, 2H), 1.99 (m,4H). (S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] — 4 — (2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide. lU NMR (CDCI3, 8) :7.75 (d,2H), 7.46 (m,lH), 7.1 - 7.3 (m, 3H), 6.95 (d,lH), 6.44 (t, IH), 4.70(m, IH), 3.3 - 4.0 (m,4H ), 3.41(m, 4H) 3.24 (dd, 2H), 2.55 (t, 2H), 2.45 (d,2H), 2.01(m,4H), 1.81 (pent,lH), 0.83 (d, 6H). (S) -N-][3-(3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4- (2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide. lH NMR (CDCI3, 8) :7.76 (d,2H), 7.2 7.5(m, 4H), 6.95 (d,lH), 6.33 (t, IH), 4.69(m, IH), 3.88(t,lH), 3.71(t,lH), 3.6 - 3.7 (m,2H ), 3.45(m, 4H) 3.23 (dd, 2H), 2.56 (t, 2H), 1.94 (m,4H), 1.26(s,9H). (S^J - N-[[3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4 — (4 - acetamidophenyl) -4- oxobutanamide. 'H NMR (CDCU, 8) : 7.2 - 7.8 (m, 7H), 6.85 (d,lH), 6.47 (t, IH), 4.67(m, IH), 3.81(t,lH), 3.3 - 3.7 (m,3H ), 3.46(m, 4H) 3.16 (m, 2H), 2.3 - 2.9 (m,6H), 2.06(s,3H). (Sp -N-[]3-(3-fluoro -4- pyrrolidinylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4- oxo - 4 -phenylbut - 2- enamide. 'HNMR (CDCI3, 8) :7.8 - 7.9 (m,3H), 7.0 - 7.6 (m, 5H), 6.93 (d,lH), 6.75 (m,lH), 4.76(m, IH), 4.02(t,lH), 3.74 (m, 3H), 3.30 (m, 4H), 1.95 (m,4H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]- 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. !HNMR (CDCI3, 8) :7.78 (d,2H), 7.33 (dd,lH),6.99 (d,lH), 6.83 (t,lH), 6.81 (d, 1H),6.38 (t, IH) 4.69(m, IH), 3.86 (t,lH), 3.79 (s,3H), 3.5 - 3.8 (m,3H ), 3.41(m, 4H) 3.20 (m, 6H), 2.73(m,4H) 2.53 (t, 2H). (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5- oxazolidinyl]methyl]- 4 - (2,4 - dimethylphenyl) -4- oxobutanamide. !H NMR (CDCI3, 8) :7.55 (d,lH), 7.33 (dd,lH), 6.96 (m,3H), 6.81(t,lH), 6.22 (t, IH), 4.69(m, IH), 3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.17(m, 6H) 2.73 (t, 2H), 2.45 (d,2H),2.51 (t,2H), 2.34(s,3H), 2.27 (s,3H). (Si)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]- 4 - oxo -4-(2- thienyl)butanamide. !H NMR (CDCI3, 8) :7.63 (d,lH), 7.55 (d,lH), 7.33 (dd, IH), 7.05 (dd,2H), 6.85(t, IH), 6.31 (t,lH), 4.69(m, lH),3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.23(m, 6H) 2.73 (m, 4H), 2.55 (t, 2H). 39 (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - J - oxazolidinyl] methyl] -4-(4- acetamidophenyl) -4- oxobutanamide. 'HNMR ( DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.73(d, 2H), 7.59 (d, 2H), 7.38 ( dd, IH), 7.08(dd,lH), 6.99 (t, IH), 4.65 (m, IH), 3.95(t,lH),3.62(dd,lH), 3.08(m, 6H), 2.66 (m, 4H), 1.97 (s,3H). (S) - N -[[ 3 - (3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] - 4 -oxo - 4 - (4 - thiomethylphenyl)butanamide. •HNMR (CDC13,8) : 7.70 (d, 2H), 7.32 (dd,lH),7.14 (d, 2H,), 6.99(dd,lH), 6.82(t,lH), 6.33 (t, IH ), 4.68 ( m, IH), 3.86 (t, IH), 3.4 - 3.8 (m, 3H), 3.20(dt, 2H ), 2.90(t,4H) 2.53(t, 2H), 2.44(s,3H), 1.67 (m,4H), 1.5 (m,2H). (S) -N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl] -4-(naphthyl) -4- oxobutanamide. 'H - NMR ( CDCI3) : 8.36 (s, IH ), 7.7 - 7.9 (m, 4H, ), 7.4 - 7.6 (m, 2H ), 7.32 (dd,lH), 6.99(d,lH), 6.78(t,lH), 6.43 (t, IH), 4.70 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.39(dt,2H), 2.86(t,4H), 2.61(t, 2H), 2.10(m,4H),1.50 (m,2H). S) -N-[[ 3- (3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide. lUNMR (CDCI3,8) : 7.75 (d, 2H), 7.37 (d,2H),7.31 (dd, IH, ), 7.00(dd,lH), 6.84(t,lH), 6.37 (t, IH ), 4.68 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.25(dt, 2H ), 2.91(t,4H) 2.54(t, 2H), 2.23(m,4H), 1.5 (m,2H), 1.26(s,9H). (S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4-oxo -4-(4- thiomethylphenyl)butanamide. 'HNMR (CDCI3, 8) : 8.08 (d, 2H ), 7.77 (dd, IH, ), 7.63(d,2H), 7.2 - 7.5 (m, 4H ), 7.12 (d,2H), 6.41 (t, IH ), 4.81 ( m, IH), 3.98 (t, IH), 3.7 - 3.9 (m, 2H), 3.54(dt,lH), 3.22(qdd,2H), 2.54(dd, 2H), 2.36(s,3H). (S) -N-[] 3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5 - oxazolidiny] methyl] -4-(2-naphthyl) -4- oxobutanamide. 'HNMR (CDCI3, 8) : 8.35( s,lH), 8.08 (d, IH ), 7.6 - 7.8(tn,5H), 7.2 - 7.6 (m, 7H ), 6.41 (t, IH ), 4.82 ( m, IH), 3.8 - 4.0 (m, 3H), 3.3 - 3.7(m,3H), 2.64(dd, 2H). (S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4 - (2',2' - dimethyl- 4 - ethylphenyl) -4- oxobutanamide. H NMR (CDCI3, 8) : 8.08 (d, IH ), 7.80 (dd, IH, ), 7.70(d,2H), 7.57(t, IH), 7.2 - 7.5 (m, 4H ), 7.08 (d,2H), 6.41 ( t, IH ), 4.80 ( m, IH), 3.7 - 4.0 (m, 3H), 3.55(dt,lH), 3.1 - 3.4(m,2H), 2.54(dd, 2H), 2.37(d,2H), 1.72(pent,lH), 0.76(d,6H). 40 (S)-N-[[3-(3-Jluoro-4- henzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide. JHNMR(CDC13, 5) :7.2 - 8.0 (m,13H), 6.95 (d,lH), 6.65 (m,lH), 4.89(m, IH), 4.18(t,lH), 3.7-4.0 (m, 3H). (S) -N-[[3-(3-Jluoro-4-benztriazolylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 -(4- acetamidophenyl) -4- oxobutanamide. !HNMR (DMSOde, 8) : 10.16 (s, IH), 8.29(t, IH), 8.12 (d, IH), 7.79 (m, 4H), 7.58 ( d, 2H), 7.4 - 7.5 (m, 4H), 4.74 (m, IH), 4.13(t,lH),3.08(dd,lH), 3.10 (t, 2H), 1.97 (s, 3H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide. lH NMR (CDCI3,8) : 7.76 (d, 2H), 7.53 (dd, 1H),7.39 (d, 2H +1H, ), 7.02(d,lH), 6.29 (t, IH ), 4.71 ( m, IH), 3.89 (t, IH), 3.79(t,lH), 3.5 - 3.7 (m, 2H), 3.38(m, 4H ), 3.24 (dd,2H), 2.92(m,4H) 2.54(t, 2H), 1.26(s,9H). (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide. JH NMR (CDCU, 8) :7.8 - 7.9 (m,3H), 7.3 - 7.7 (m, 5H), 6.8 -7.0 (m,3H), 4.81(m, IH), 4.05(m,lH), 3.75 (m, 3H), 3.49 (m, 4H), 3.10 (m,4H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(fi- naphthyl) -4- oxobutanamide. !H NMR (CDCI3, 8) : 8.35 (s, IH), 7.7-8.0 (m, 4H), 7.3-7.7 (m, 5H), 7.01 (m, IH), 6.48 (m, IH), 4.74 (m, IH), 3.80 (m, 3H), 3.60 (m, IH), 3.37 (m, 6H), 2.93 (m, 4H), 2.60 (m, 2H) (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4- (4- chlorophenyl) -4-oxobutanamide. !H NMR (CDCI3, 8) : 7.74 (d, 2H), 7.54 (d, IH), 7.34 (d, 2H+1H), 6.98 (d, IH), 6.35 (t, IH), 4.78 (m, IH), 3.88 (t, IH), 3.5-3.8 (m, 3H), 3.38 (m, 4H), 3.22 (dd, 2H), 2.93 (m, 4H), 2.54 (t, 2H). (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4 - (2,4 - dimethyl- 4 ethylphenyl) -4- oxobutanamide. lH NMR (CDCI3, 8) : 7.95 (m, IH), 7.74 (d, 2H+1H), 7.77 (d, 2H), 7.07 (d, IH), 6.38 (t, IH), 4.76 (m, IH), 3.91 (t,lH), 3.4-3.8 (m, 3H), 3.58 (m,4H), 3.25 (dd, 2H), 3.1 (m, 4H), 2.54 (t, 2H), 2.46 (d, 2H), 1.80 (pent, IH), 0.85 (s, 3H), 0.82 (s, 3H). Microbiology: Pharmacological testing The compound of formula (I) of the present invention displayed antimycobacterial activity when tested by in vitro growth inhibition assay and agar incorporation methods. The minimum inhibitory concentrations (jag/ml) obtained for representative compounds of formula (I) 41 against M. tuberculosis including sensitive and resistant strains are summarized in Table-I. The MIC value of a representative preferred Compound No. 30 of formula I against different species of mycobacteria is summarized in Table-II. in vitro Growth Inhibition assay The ability of the compounds 1-78 of formula (I) of this invention to inhibit the growth of Mycobacterium species was determined by the BACTEC 460 TB system. The reference strain M tuberculosis H37Rv ATCC 27294 was grown in Middlebrook 7H9 broth containing 10% ADC supplement at 37°C on a rotay shaker at 150 rpm for grown for 7days. The turbidity of the culture was adjusted to 1.0 Mc farland. The BACTEC 7H12B medium vials were seeded with 0.1ml of the 1.0 Mc farland adjusted M. tuberculosis culture. In the control vials 0.1ml of the culture was added after lOOfold dilution of the initial inoculum. Stock solution of lmg/ml of each compound was prepared in DMSO in separate sterile tubes. The compounds were further diluted to concentration of 25 ^g/100 ul, 0.1ml was than added to the 7H12B vial containing mycobacterial culture so that final concentration of the compound 6.25 u.g/ml. The cap in all the vials were cleaned with isopropanyl alcohol and kept in racks. The vials were then incubated at 37°C without shaking. Test vials was read daily on the BACTEC system till the GI of the control vial reached > 30.Once the GI in the control reached 30 AGI (GI = GI (n> - GI („.i) ) was determined for all test and control vials. If AGI of test vial is less than that of the control vial the culture was sensitive to the test compound. in vitro Agar Dilution assay MIC of compound of formula (I) of this invention against strains of Mycobacterium were determined by a reference agar dilution method as per the NCCLS- M24-T2. recommendations. The compounds were dissolved in DMSO and diluted twofold to obtain ten serial dilutions of each compound. Appropriate volume of compounds were incorporated into duplicate plates of Middlebrook7H10 agar medium supplemented with 10% Middlebrook supplement oleic acid-albumin-dextrose (OADC) enrichment at concentration of 0.03u,g/ml to 16\|j,g/ml. Test organisms (mycobacterium strains) were grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement. After 7 days of incubation at 37°C the broths were adjusted to the turbidity of 1.0 McFarland standard; the organism were further diluted 10 fold in sterile water containing 0.10% Tween-80. The resulting mycobacterial suspensions were spotted (3-5jxl/spot) onto drug supplemented 7H10 media plates. The plates were sealed and incubated at 37°Cfor 3-4 weeks in upright position. The MIC was recorded as the lowest dilution of the drug that completely inhibited the growth of test organisms. Test isolates included 10 clinical isolates that were generally susceptible to common tubercular agents and 10 strains that were resistant to one or more standard anti tubercular drugs. Appropriate reference strains and control drug was included in each batch of test. 42 in vivo studies: The efficacy of the compound of formula (I) of this invention was also evaluated in murine model of pulmonary tuberculosis. Mycobacterium tuberculosis cultures grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement at 37°C for 7 days on a rotary shaker. For, animal inoculation liquid cultures were declumped by brief sonication and were diluted appropriately in 7H9 broth to obtain a concentration of lxl07CFU's/ 0.2ml. Four-week-old male outbred Swiss albino mice housed in a pathogen free, biosafety level 3 environment within micro isolator cages were used throughout the study. Infections were produced by intravenous inoculation into caudal tail vein of 0.2ml of declumped M. tuberculosis suspension. Following infection, mice were randomly distributed in different groups of six each. Treatment for initial study was started one day after infection. For, treatment Compound No. 30 of formula I was dissolved in 10% PEG. Isoniazid was dissolved in sterile water. The drugs were prepared each morning prior to administration. Therapy was given 5 days per week for four weeks. All the agents were administered by gavage and were dosed at 50,25,12.5mg / kg of body weight. Control group of infected but untreated mice were killed at the initiation of therapy (early control) or at the end of the treatment period (late control). Mice were sacrificed by cervical dislocation 3-5 days after the administration of the last dose of drug. The spleens and right lung were removed aseptically and homogenized in tissue homogeniser. At least 4 serial tenfold dilution of the homogenate was plated onto selective Middlebrook 7H11 agar plates in duplicate. The colony counts were recorded after incubation at 37°C for 4 weeks. The viable cell counts were converted to Logio values. A compound showing 2 Log reduction in viable counts compared to the controls was considered significant. The in vivo data for a representative compound of formula (I) is given in Table-II. Acute toxicity of Compound No. 30 of Chart-I was estimated in mice and the LDo was found to be >1000 mg/kg P. O. 43 Table-I: in vitro activity of compounds 1 to 58 of formula (I), Compound No. Growth inhibition of M.tuberculosis 27294 MIC (fig/ml) against M.tuberculosis 27294 Clinical isolates Sensitive Resistant 1 + 16 4-16 >16 2 + 8 8 8 8 + 2 .5-2 2-4 13 + 2 2 2-4 14 + 0.25 0.25-0.5 4->16 15 + >16 >16 >16 16 + 0.5 0.5 0.5(>16) 17 + 0.5 1.0 0.5-1.0 18 + 4- 1-4 8->16 19 + 2 1-2 2 20 + 1 1-2 2-4 21 + 0.5 0.5-2 0.5(>16) 25 + 4 4-16 4->16 27 + >16 >16 >16 28 + 0.5 1-2 2-8 30 + 0.5 0.5 0.5-2 31 + 1 1-2 1-4 32 + 0.25 0.25-0.5 4-(>16) 33 + 0.5 1 0.5-2 34 + >16 >16 >16 35 + 4 2-4 4-8 36 + 4 4-8 4-8 44 Table-I Contd.... 39 + 2 2-4 2-8 40 + 1 1-2 1-2 43 + 1 0.5-1.0 1-2 44 + 1 0.5-2 1-4 45 . + 2.0 2-4 2-4 46 + 2 2-4 2-8 47 + 1 1-2 2-4 48 + 2 2-4 2-8 49 + 4 4-16 4-16 50 + 2 2-4 2-4 51 + 8 8->16 8->16 52 + 2 2 4->16 53 + >16 >16 >16 54 + 8 8-16 >16 55 + >16 >16 >16 56 + >16 >16 >16 57 + 16 16->16 >16 58 + 8 8-> 16 8-> 16 Isoniazid + 0.25 0.12- .25 8 - >16 Linezolid + 0.5 0.25-0.5 1.0-2.0 Table-II MIC values of compound of formula (I) against different species ofMycobacteria Sr. No. Compound No. MIC (ug/ml) M. tuberculosis M.avium- intracellular complex M.fortuitum M.kansai Sensitive Resistant 1 Compound 30 of formula I 0.50 0.50-2.0 8.0->16.0 >16.0 8.0 2 Isoniazid 0.25 4.0-> 16.0 8.0->16.0 >16.0 >16.0 45 Table-m in vivo activity of Compound of formula (I) against M. tuberculosis ATCC 27294" infection in Swiss albino mice Sr. No. Drug& Dose b (mg/kgday" ') or group Mean Logio No. of CFU Mean Logio No. of reductionc Lung Spleen Lung Spleen 1 Compound 30 of Chart-I 50mg/kg 25mg/kg 12.5mg/kg 2.12 2.21 4.34 2.09 2.13 4.30 2.40 2.30 0.20 2.53 2.49 0.26 2 Isoniazid 50mg/kg 25mg/kg 12.5mg/kg 2.03 2.11 2.95 1.92 2.11 2.94 2.49 2.41 1.57 2.70 2.51 1.68 3 Infected early control 4.52 4.62 4 Infected late control 6.57 6.37 a- inoculation of logio:- 7.00 Mycobacteria. b- mice were dosed 5 day/week for 4 weeks. From day 1 -28. c- difference in mean logio number CFU from that of early controls. The compound of formula I of this invention may be administrated to a subject such as a human being or an animal in need of such an administration through any route appropriate to the condition to be treatede. Suitable routes of administration include oral, rectal, nasal, topical (both buccal and sublingual), vaginal and parenteral (including subcutaneous, intramuscular, intradermal, intrathecal and epidural). Pharmaceutical compositions of compound of formula I can be prepared in adjunction with inert pharmaceutically acceptable carriers, which can either be solid or liquid. Solid form preparations include powders, tablets, dispersible granules, capsules, cachets, suppositories and ointments. The solid carriers can be one or more substances which may act also as diluents, flavouring agents, solubilisers, lubricants, suspending agents, binders or tablet disintegrating agents. It can also be finely divided solid which is in admixture with finely divided active compound. Suitable solid carriers are lactose, pectin, dicalcium phosphate, microcrystalline cellulose, sucrose, kaolin, dextrin, gelatin, starch, tragacanth, low melting wax, coca butter and the like. Liquid preparations include solutions, suspensions and emulsions, e.g. solutions of compound of formula I in water or water-propylene glycol mixture for parenteral injection. Liquid preparations can also be formulated along with non-ionic surfactants and edible oils such as corn, peanut and sesame oils. Aqueous solutions for oral use can be prepared by dissolving the active component in water and adding suitable colorants, flavours stabilizing and thickening 46 agents, as required. Aqueous suspension for oral use can be made by dispersing the finely divided active component in water with a viscous material, e.g. natural or synthetic gums, resins, methyl cellulose, sodium carboxymethyl cellulose and othe known suspending agents. The adjuvants may also include preserving agents and anti-oxidants. Compositions for topical application may take the form of liquids or gels, containing a therapeutically effective concentration of compound of formula I admixed with a dermatologically acceptable carrier. The pharmaceutical preparations may be in unit dosage form. In such form, the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage can be in the form of tablets, capsules, powdersin vials or ampoules, ointments, gels, creams or any other form. The quantity or concentration of the active compound in such unit dose preparations may be varied or adjusted according to the particular application and potency of the active ingredient. 47 A compound of formula (I) and its pharmaceutical^ acceptable salts wherein, A is either hydrogen or fluorine, B is either hydrogen or fluorine, A and B together is hydrogen and fluorine, Ri is a group of formula, wherein, Q is either an alkyl group of two carbon atoms, an alkene group of two carbon atoms or an alkyne group of two carbon atoms Y is oxygen, sulfur or an amino function of formula NR3 wherein, R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or branched; cycloalkyl of 3-7 carbon atoms; CHO, -COOH, -COOR,; COCR,; CN; aryl or heteroaryl wherein, Rt is an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms. Ar is a substituted phenyl ring or a substituted pyridine ring of formula —O-R3 or Ar is a five membered ring of formula 48 or Ar is a fused bicyclic phenyl or pyridine ring of formula wherein, M is either CH or N Z is CH, NH, O, or S, X is a group selected from OR,, NR4R5, N02, SR,, SOOR,, SOONR4R5, F, CI, Br or I, wherein R4 is as defined hereinbefore, and and R3 is as defined hereinbefore R5 is hydrogen or R4 R2 is selected from the groups shown below, and the corresponding N-oxides thereof. A compound according to Claim 1 wherein in said compound of formula I Aryl is phenyl substituted with (0) or (1) of F, CI, "OCH3, "OH, "NH2, CrC4 alkyl, 0-C(0)-OCH3," N02or"CN. 49 3. A compound according to Claim 1 wherein said compound of formula I is selected from the group consisting of: 1) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 2) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 3) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 4) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide. 5) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 6) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 7) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide. 8) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 9) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 10) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 11) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide. 12) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide. 13)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 14) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide. 15) (S) - N -[ [ 3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide. 16) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl 1 methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide. 17) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 50 18) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 19) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl]-4-oxo-4-(2-thienyl)butanamide. 20) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 21)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide. 22) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 23) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 24) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 25) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 26) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) — 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 27) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 28) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide. 29) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide. 30) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide. 31)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (2 - thienyl)butanamide - N - oxide. 32) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide. 33) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N -oxide. 34) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 51 35) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4- oxobutanamide. 36) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4- oxobutanamide. 37) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4- oxobutanamide. 38) (S) - N -[ [ 3 - (3 - fluoro - 4 - benztriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 39) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 40) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 41) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4 - oxobutanamide. 42) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 43) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 44) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide. 45) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 46) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 47) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide. 48) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide. 49) (S) - N .-[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 50) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 51) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 52) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide. 52 53) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 54) (S) -N-[[3-(3- fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 55) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 56) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -■ ( 4 - thiomethylphenyl )butanamide. 57) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2 - naplrthyl) - 4 - oxobutanamide. 58) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide. 59) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 60) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 61)(S)-N-[[3-(3- fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 62) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 63) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 64) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide. 65) (S) - N -[ [ 3 - ( 5 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 66) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (4 - thiomethylphenyl)butanamide. 67) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 68) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 69) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide. 70) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 53 71) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 72) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 73) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 74) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 75) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 76) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) --2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2 - naphthyl) - 4 - oxobutanamide. 77) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - '2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 78) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide. - ' 4. A compound as claimed in claim 3 wherein said compound of formula I is selected from the group of N-oxide of the said compounds 1 to 78. 5. A pharmaceutical composition comprising a) atleast one of I) any compound of claims 1 to 4 and II) its pharmaceutically acceptable salts and b) a pharmaceutically acceptable carrier. 6. A pharmaceutical composition according to claim 5 comprising a solid or liquid preparation. 7. A pharmaceutical composition as claimed in anyone of claims 5 to 6 for oral or parenteral administration. 8. A method of preparation of the compound of formula I and/or its pharmaceutically acceptable salts comprising: coupling of the amino fragment of compound of formula II 5^ (II) with a carboxylic acid of formula III in the presence of an acid activating group or a dehydrating agent in a suitable solvent. (Ill) wherein R2 has the same meaning as given in claim 1. 9. A method as claimed in claim 8 wherein the compound of formula II is preferably selected from (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine,(S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, S) - N -[3 - (3 - fluoro - A - benzotriazolylphenyl) - 2 - oxo - 5 -oxazolidinyl] methyl amine, and (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine. 10. A method as claimed in anyone of claims 8 or 9 wherein the compound of formula III is selected from 4-(2-Naphthyl)-4-oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic acid, 4-oxo-4-(2' methy lpropyl)phenylbutanoic acid, 4-Oxo-4-(2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 - 5S oxobutanoic acid,4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, . 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 - phenyl - but - 2 - ynoic acid. 11. A compound of formula I, its pharmaceutically acceptable salts and pharmaceutical compositions obtained thereof substantially as herein described and illustrated. Dated this 5th day of March 2005 Dr. Sanchita Ganguli Of S. MAJUMDAR & CO. Applicants' Agent 5t F0RM2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See section 10; rule 13) 1. Title of the invention. - OXAZOLIDINONE DERIVATIVES, PROCESS FOR THEIR PREPARATION AND THEIR USE AS ANTIMYCOBACTERIAL AGENTS 2. Applicants) (a) NAME : LUPIN LIMITED (b) NATIONALITY : An Indian Company (c) ADDRESS : 159, C.S.T. Road, Kalina, Santacruz (East), Mumbai - 400 098, Maharashtra, India 3. PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed FIELD OF THE INVENTION The present invention relates to novel compounds belonging to the class of oxazolidinones useful in the treatment of acid fast organisms such as Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium spp. The present invention further relates to methods for preparation of the novel compounds and to pharmaceutical compositions containing the novel compounds useful in the treatment of tuberculosis. BACKGROUND OF THE INVENTION Tuberculosis (TB), an infectious disease caused by the bacterium Mycobacterium tuberculosis is transmitted mainly through air, affecting most often the lungs. When persons with pulmonary TB cough they produce tiny droplet nuclei containing M. tuberculosis, which remain suspended in air for a prolonged period of time. A person who breathes the air containing the aforesaid droplet nuclei containing M. tuberculosis can become infected with TB. TB, one of the three major infectious diseases in the priority list of the World Health Organization's (WHO) agenda kills about two million people around the world every year. About six million new cases are reported every year and nearly 20% of adult deaths and 6% of infant deaths are attributable to the disease (C. Dye et. al., J. Am. Med. Ass., 1999, 282, 677-686). About a billion people are expected to be affected by TB by the year 2020, with 35 million likely to succumb to the disease (WHO Fact Sheet No. 104, Global Alliance for TB Drug Development- Executive Summary of the Scientific Blueprint for TB Development : http://www.who.int/inf-fs/en/factl04.html). With the emergence of the AIDS epidemic and the increase in cases of HIV coupled with TB as well as the continued resistance of M. tuberculosis to isoniazid and rifampicin, the two most powerful anti-tubercular drugs available today there is an urgent need for new anti-tubercular drugs to combat the killer disease (S. H. E. Kaufmann et. al., Trends Microbiol., 1993, 1,2-5 ; B. R. Bloom et. al., N. Engl. J. Med., 1998, 338, 677-678). Although, many new compounds are becoming available for fighting a number of infectious diseases, the number of such compounds having antimycobacterial activity are few. This could partly be due to the complexity of research involved and partly due to business considerations (B. N. Roy et. al., J. Ind. Chem. Soc, April 2002, 79, 320-335 and references cited therein). However, renewed thrust in research in the last decade has resulted in development of new antimycobacterial compounds, a) differing widely in structures, b) having different mode/mechanism of action, c) possessing favourable pharmacokinetic properties, d) which are safe and have low incidence of side-effects, and e) which provide a cost-effective dosage regimen. 2 Among the aforesaid new compounds, the oxazolidinones first developed during the mid-1980s (W. A. Gregory et. al., J. Med. Chem., 1989, 32,1673-1681 and 1990,33,2569-2578 ; C-H Park et. al., J. Med. Chem., 1992, 35, 1156-1165) are a unique class in themselves. The in vivo results for some of the oxazolidinones show that they are active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, including resistant strains such as methicillin-resistant Staphylococcus aureus [MRSA], methicillin-resistant Streptococcus epidermidis [MRSE], penicillin-resistant Streptococcus pneumoniae [PRSP], vancomycin-resistant enterococci [VRE], etc. (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999,9 (5), 625-633 and the references contained therein). The oxazolidinones inhibit bacterial protein synthesis at a very early step in the initiation of complex formation involved in the process of translating mRNA into protein. The oxazolidinones, in general, are not cross-resistant with any known antibiotic because of this unique mechanism (D. C. Eustice et. al., Antimicrob. Agents Chemother., 1988, 32, 1218 and Biochem. Biophys. Res. Commun., 1988,150. 965). A feature of the oxazolidinone molecule is that only those compounds, which are enantiomers with a (5S)-acetamidomethyl configuration in the left side of the molecule are known to exhibit antibacterial activity (W. A. Gregory et. al., J. Med. Chem., 1989, 32, 1673-1681). Another feature is that most of such antibacterial compounds invariably carry a (substituted) phenyl ring attached to the nitrogen atom of the oxazolidinone ring in the right side of the molecule (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999, 9 (5), 625-633 and the references contained therein). The most promising compound among the N-phenyl oxazolidinones, which has been approved for human use is (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidin-yl]methyl]-acetamide), commonly known as linezolid (M. Barbachyn et. al., WO 995/07271). Linezolid possesses good in vitro and in vivo potency against most of the Gram-positive bacteria, including resistant strains {Drugs of the Future, 1996,21.(11), 1116-1123). The left hand side i. e. position 5- and the right hand side i. e. position 3- respectively of the oxazolidinone ring nucleus allows for many variations and has resulted in the discovery of a large number of compounds having antimicrobial and antibacterial properties. Such representative compounds, albeit not meant to be limiting are disclosed in the following prior art references. These are: i) US 4,942,183 (Gregory et. al.) and US 4,948,801 (Carlson et. al.) collectively disclose certain 3-substituted phenyl- 5-aminomethyl oxazolidinones, possessing useful antibacterial activity, ii) US 5,529,998 (Habich et. al.) discloses certain 3-benzoxazoyl- and benzothiazolyl-5- acetyl amino methyl oxazolidinones, useful as antibacterial medicaments. 3 iii) US 5,565,571, US 5,654,428, US 5,756,732, US 5,801,246 and US 5,929,248 (Barbachyn et. al.) collectively disclose several substituted aryl and heteroaryl phenyloxazolidinones carrying an acetyl aminomethyl function at the 5-position, specifically oxazolidinones having an aryl or heteroaryl group at the para position of the 3-phenyl ring and additional substituents at the meta positions of the 3-phenyl ring, which are useful as antibacterials. iv) US 5,652,238 (Brickner et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a hydroxyl acetyl piperazine moiety, active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, as well as anerobic organisms such as bacteroides and Clostridia species as well as acid-fast organisms such as Mycobacterium tuberculosis. v) US 5,684,023 (Riedl et. al.) discloses certain 3- benzofuranyl- and benzothienyl oxazolidinones, carrying an azido, hydroxy or acetyl aminomethyl group at the 5-position, useful as antibacterial medicaments. vi) US 5,688,792 (Barbachyn et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a (substituted)-morpholine. Such compounds are useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp. vii) US 5,719,154 (Tucker et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the said substitution being a pyrimidinyl or pyradazinyl group. Such compounds are useful as antimicrobial agents. viii) US 5,736,545 (Gadwood et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a five membered heterocycle ring, in particular an azolyl ring. Such compounds are useful in the treatment of microbial infections. ix) US 5,792,765 (Riedl. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-substituted phenyloxazolidinones, the substitution being a heterocyclic moiety, useful as antibacterial medicaments. x) US 5,861,413 (Habich et. al.) discloses certain 2-oxo and 2-thio-l,2-dihydroxyqoinolinyl-1-oxazolidinones, useful as antibacterial medicaments. xi) US 5,880,118 (Barbachyn et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a 4 substituted thiomorholine moiety i. e. oxazine and thiazine derivatives, useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp. xii) US 5,910,504 and US 6,124,334 (Hutchinson et. al.) collectively disclose certain substituted 5-acetyl aminomethyl-3- phenyloxazolidinones substituted at the para position of the 3-phenyl ring with a heteroaromatic moiety, which is five membered having one to four nitrogen atoms or alternatively, a benzoannulated five-membered heteroaromatic ring having one to four nitrogen atoms, useful as antibacterials. xiii) US 6,069,160 (Stolle et. al.) discloses certain substituted 5-acetyl aminomethyl-3-benzocyclopentaneoxazolidinones, containing an heteroatom, useful as antibacterial medicaments. xiv) US 6,227,868 Bl and US 6,410,728 (Sciotti et. al.) collectively disclose certain 5-acetyl aminomethyl-3-phenyloxazolidinones carrying an acetylenic moiety on the 3-phenyl ring, useful for treating bacterial infections, psoriasis, arthritis and toxicity due to chemotherapy. xv) WO 93/23384 (Hutchinson et. al.) discloses certain substituted 5-acetyl aminomethyl-3 -phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, useful for treatment of microbial infections caused by staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium. xvi) WO 97/10223 (Gadwood et. al.) discloses certain substituted 5-acetyl aminomethyl-3-aminoaryl oxazolidinone N-oxide compounds, which are exceedingly water soluble and useful in preparation of pharmaceutical compositions for combating a number of human and veterinary pathogens, staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium, Mycobacterium spp. and Mycoplasma spp. xvii) WO 98/01446 and WO 98/01447 (Betts et. al.) collectively disclose certain substituted 5-acetyl aminomethyl3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a six-membered heteroaryl ring containing two or three ring nitrogen atoms as the only ring heteroatoms, useful as antibacterial agents. xviii) WO 99/02525 (Thomasco et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted by a thiadiazolyl or oxadiazolyl moiety, useful as 5 antimicrobial agents, effective against a number of human and veterinary pathogens, including Gram-positive and Gram-negative aerobic bacteria. xix) WO 99/37630 (Gordeev et. al.) discloses oxazolidinone combinatorial libraries, compositionscontaining the same and methods of preparation thereof involving solid phase synthesis, which provides the said compounds for high-throughput screening. xx) W099/37641 (Bartel. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-bicyclene-substituted oxazolidinones, useful as antibacterial medicaments. xxi) WO 01/09107 (Gordeev et. al.) discloses certain 3-heteroaryl-5-acetyl aminomethyl oxazolidinones, substituted by a thioacyl, aminocarbonyl, alkoxycarbonyl, aminothiocarbonyl, alkoxythiocarbonyl and alkylthiocarbonyl group, useful in treating or preventing an infectious disorder in humans or animals. xxii) WO 01/42242 (Paget et. al.) discloses certain substituted 5-acetyl aminomethyl 3-substituted phenyloxazolidinones, the substitution being a bicyclic heterocyclic system, useful as antibacterial agents. xxiii) WO 02/06278 (Mehta et. al) discloses certain substituted 3-phenyl oxazolidinones and to process for synthesis of the same, the said compounds useful as antibacterial agents, effective against a large number of human and veterinary pathogens, including Gram-positive bacteria and acid fast organisms such as Mycobacterium tuberculosis. xxiv) WO 02/20515 (Madar et. al.) discloses heterocyclic phenyloxazolidinones, useful for treating bacterial infections. However, only a few of the disclosures described hereinbefore provide compounds that can be used as antimycobacterials, while most of the others are silent about the antimycobacterial activity of the disclosed compounds. A need, therefore, exists for new compounds possessing potent antimycobacterial properties for treatment of TB, which as mentioned hereinearlier is assuming alarming proportions. OBJECTS OF THE INVENTION It is thus the basic object of the present invention to synthesize, identify and provide new compounds belonging to the class of oxazolidinones, possessing potent antimycobacterial properties especially for treatment of acid fast organisms such as Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M. kansai. Another object is directed to providing antimycobacterial pharmaceutical composition effective in inhibiting/treating the generation of mycobacterial conditions/cells including Mycotacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M fortuitum and Mkansai. 6 Yet another object is directed to providing a method of treating/inhibiting mycobacterial cells/conditions involving the administrations of effective amount of the novel antimycobacterial compound and/or its salts /composition of the invention. SUMMARY OF THE INVENTION Thus according to the basic aspect of the present invention there is provided compound of formula (I) and its pharmaceutically acceptable salts thereof wherein, A, B = H, and/or F Ri is a group of formula wherein, Q is CH2-CH2, CH=CH, or C=C Y is O,S or NR3 wherein, R3 is Ci - C4 alkyl (straight, branched, unsaturated), cycloalkyl, COOH, COOR,, CHO, COCR4, CN, aryl, heteroaryl wherein, R is an alkane of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms, and Ar is an aromatic carbocycle represented by 7 wherein, X is OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, Br, CI, F, or I, M is-CHorN,and Zis-CH,-NH,OorS and wherein, R3 and R4 are as described hereinbefore, and R5 is H, or same as R4, and R.2 is selected from the groups shown below, and the corressponding N-oxides thereof Heteroaryl or Heterocycloalkyl wherein K is O, S, SO, S02, or CH2 According to another aspect of the invention there is provided a pharmaceutical composition comprising: i) atleast one of an antimycobacterially effective amounts of compound of formula I and pharmaceutically acceptable salts there of; and ii) a pharmaceutically acceptable carrier. According to yet another aspect of the present invention there is provided a method of inhibiting growth of mycobacterial cells such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M.kansai.,comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof. 8 According to yet another aspect of the present invention there is provided a method of treating mycobacterial conditions such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M kansai, comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof. According to another aspect, there is provided a process for the manufacture of the compound of formula I or its pharmaceutically acceptable salts comprising : coupling the amino fragments of compound of formula II with the carboxylic acid fragment of formula III. The above disclosed compound of formula I its pharmaceutically acceptable salts thereof are found to have antimycobacterial properties and the same in admixture with pharmaceutically active additives, an be administrated orally or paranterally for treatement of mycobacterial conditions especially TB. DETAILED DESCRIPTION OF THE INVENTION In the pharmaceutically active compound of formula (I) of this invention, the definition of the symbols and groups A, B, Rt and R2 are as follows : A is either hydrogen or fluorine, B is either hydrogen or fluorine, A and B together is hydrogen and fluorine, When A is hydrogen, B is fluorine and vice-versa. R1 represents a group of formula, Q is either an alkyl group of two carbon atoms (CH2-CH2), an alkene group of two to carbon atoms (CH=CH), or an alkyne group of two carbon atoms (C=C) 9 Y can either be oxygen, sulfur or an amino function of formula NR3, wherein R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or branched. Suitable alkyl groups are methyl, ethyl, n-propyl, n-butyl, iso-propyl, iso-butyl, tert- butyl, ethylene, propylene, 1, butene, both the geometric isomers of 2-butene i. e.(cis)-2-butene and (trans)-2-butene, and iso-butylene. or R3 is a cycloalkyl group of 3-7 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl, or R3 is a carboxylic acid group (-COOH) or a carboxylic acid ester of formula-COOR4, wherein R4 is H, an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms. R3 is further an aldehyde (-CHO), an acetyl group (-COCR4), wherein R4 is as mentioned hereinbefore or R3 is a nitrile (CN), aryl or heteroaryl, wherein Aryl is phenyl substituted with (0) or (1) of-F, -CI, -OCH3, -OH, -NH2, -CrC4 alkyl, -O-C(O)- OCH3,-N02or-CN,and Heteroaryl or Ar is a five membered ring of formula or Ar is a fused bicyclic phenyl or pyridine ring of formula 10 The group Ar is a substituted phenyl ring or a substituted pyridine ring of formula wherein, M is either CH or N; Z is -CH, -NH, O or S and R3 is as defined hereinbefore, X is a group selected from OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, F, CI, Br or I, wherein R4 is as defined hereinbefore, and R5 is hydrogen or R4. R2 is selected from the groups shown below, and the corresponding N-oxides thereof. Heteroaryl or Heterocycloalkyl wherein K is O, S, SO, S02, or CH2 The preferred novel compounds of formula (I) that form part of this invention, are as follows. The following compounds 1 to 78( named as per IUPAC or CAS nomenclature) are preferred compounds of formula (I) of the invention. 1. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide. 2. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 3. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 4. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide. 5. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 11 6. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide. 7. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide. 8. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 9. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 10. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 11. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methylphenyl) - 4- oxobutanamide. 12. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - (4 - methylphenyl) - 4- oxobutanamide. 13. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 14. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide. 15. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide. 16. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide. 17. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 18. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 19. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide. 20. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - (2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 21. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide. 22. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 23. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 12 24. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazohdinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 25. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazohdinyl methyl] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 26. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazohdinyl ] methyl - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide. 27. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 28. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl - 4 - oxo - 4 -( 2 - thienyl)butanamide. 29. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide. 30. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide. 31. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide. 32. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide. 33. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N - oxide. 34. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 35. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methoxyphenyl) - 4- oxobutanamide. 36. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - chlorophenyl) - 4- oxobutanamide. 37. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2,4 - dimethylphenyl) - 4- oxobutanamide. 38. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benztriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 39. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 40. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 41. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 13 42. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 43. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide. 44. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide. 45. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 46. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 47. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide. 48. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide. 49. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 50. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 51. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 52. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 -( 2 - thienyl)butanamide. 53. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 54. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 55. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - phenylbut - 2- enamide. 56. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo- 4 - ( 4 - thiomethylphenyl )butanamide. 57. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2 - naphthyl) - 4 - oxobutanamide. 58. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide. 59. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 14 60. (S) - N -[ [ 3 - (3 - fluoro—4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 61. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbut - 2- enamide. 62. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 63. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide. 64. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide. 65. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 66. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - (4 - thiomethylphenyl)butanamide. 67. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - ( 2 - naphthyl) - 4 - oxobutanamide. 68. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 69. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide. 70. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 71. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 72. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 73. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 74. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 75. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 76. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 77. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 15 78. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 — oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide. The respective N-oxides of the group R2 of the compounds of formula I listed above also form a novel aspect of the present invention. The pharmaceutically active compounds of formula (I), the corresponding N-oxides of the group R2 and pharmaceutically acceptable salts thereof of this invention can be prepared by methods known to one skilled in the art. Typically, compounds of formula (I), can be prepared by coupling of the amino fragment of formula (II) Scheme-! General method for synthesis of compounds of formula (I) In a typical experiment, the amine compound of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinbefore is dissolved in a 1:1 mixture of tertahydrofuran and water or a 1:1 mixture of methylene chloride and water. To the solution is added the carboxylic acid compound of formula (III), followed by addition of 1-hydroxybenztriazole (HOBt). The resulting mixture is cooled to a temperature of 0-5° C to which l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 1.1 Eq.) is added and gradually allowed to warm to room temperature and agitated at this temperature for 24 hours. At the end of 17 the reaction, a solution of saturated aqueous sodium bicarbonate is added and the organic phase separated from the aqueous phase. Evaporation of the solvent and chromatography of the residue over silica gel affords compound of formula (I), generally as white solids. The N-oxides of the group R2 of compound of formula (I) thus obtained are preferably prepared by addition of m-chloro perbenzoic acid (m-CPBA) to a cooled solution of the compound of formula (I) in a chlorinated hydrocarbon solvent such as methylene chloride and ethylene chloride and thereafter agitating the reaction mixture at room temperature for 12-15 hours. Evaporation of the solvent under reduced pressure, followed by chromatography of the residue over silica gel affords the corresponding N-oxides in high purity. The N-oxides thus prepared, while retaining most of the antimycobacterial activity of the corresponding deoxo compound exhibit exceedingly high water solubility over the deoxo analogue, thereby helping in manufacture of suitable iv formulations, which forms an important aspect of this invention. The starting materials required for synthesis of compound of formula (I), thus involve the amine compound of formula II and the carboxylic acid compound of formula III. The amine compound of formula II can be selected from i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vi) (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, and viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine. 18 The carboxylic acid compound of formula III can be selected from 4-(2-Naphthyl)-4- oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic acid, 4-oxo-4-(2'methylpropyl)phenylbutanoic acid, 4-Oxo-4- (2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 - oxobutanoic acid,4 - (2,4 - dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 - phenyl - but - 2 - ynoic acid. 20 Thus, the starting amines of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinearlier are prepared as per the method disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33, 2569-2578; C. Wang et. al., Tetrahedron, 1989, 45, 1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO 95/25106 and WO 97,21708. The method is essentially summarized in Scheme-II. In a typical method, morpholine, thiomorpholine, piperidine, 4-benzyl piperazine, pyrrolidine, 1,2,4-triazine, 12,3-benzotriazine, benzyl amine, a heterocycloalkyl or a heteroaryl moiety etc., each one of which corresponds to the group R2 defined hereinbefore is reacted with 3,4-difluoro nitrobenzene in the presence of a base and a solvent to give the corresponding derivative in which the fluorine atom at 4-position is substituted by the group R2. The nitro group in the compound thus obtained is reduced to amino group, which is thereafter protected by a suitable protective group. Reaction of the N-protected compound thus obtained with (R)-glycidyl butyrate in the presence of a strong base like n-butyl lithium leads to formation of the 5-hydroxymethyl oxazolidinone ring. The hydroxy group in the compound thus obtained is converted to sulfonyl derivative, for e.g. a methanesulfonyloxy (mesyl) or a p-toluenesulfonyloxy (tosyl) derivative by reaction with methanesulfonyl chloride or p-toluenesulfonyl chloride respectively. Reaction of the respective mesyl or tosyl derivative with sodium azide gives the corresponding azide, which is converted to the amine compound of formula (II) by standard methods, for e.g. by reaction with a triaryl/trialkyl phosphine, followed by hydrolysis. The starting carboxylic acid fragments of formula (III), wherein the group Ar has the same meaning as defined hereinearlier are prepared as per the method disclosed in Org. Reactions, 1949, 5, 229-289; Quart. Rev. Chem. Soc, 1954, 8, 355-379; Chem. Rev., 1955, 55, 229-281, and J. Am. Chem. Soc, 1947, 69, 1784-1786. The method is essentially summarized in Scheme-HI. Scheme-Ill General method for synthesis ofalkane and alkene carboxylic acid s of formula (HI) In a typical method, the aromatic compound Ar-H, wherein Ar is as defined hereinbefore is reacted with succinic anhydride in the presence of a Lewis acid, such as anhydrous aluminium chloride and in the presence of an anhydrous solvent and the mixture heated to 100° C to give the carboxylic acid derivatives of formula (HI), wherein Q is alkyl of 1-4 carbon atoms. 23 Similarly, compounds of formula (III), wherein Q is an alkene (CH=CH) are prepared by reaction of the aromatic compound Ar-H, wherein Ar is as defined hereinbefore with maleic anhydride under the same conditions mentioned hereinbefore. Compounds of formula (III), wherein Q is an alkyne (C=C) are prepared by reaction of propiolic acid ester with an aldehyde of formula Ar-CHO in the presence of butyl lithium and in the presence of an aprotic solvent such as THF at -78° C to give the corresponding secondary alcohol, which is oxidized to the keto derivative using manganese dioxide as the oxidizing agent. Saponification gives the carboxylic acid derivative of formula (ID) [ US 4,929,741 (A. Fischili et. al.) ] The synthesis is summarized in Scheme-IV. P = any protective group The synthesis of compound of formula (I) of this invention and the synthesis of the respective starting material amines of formula (II) and the carboxylic acids of formula (III) are further described herein in detail. SYNTHESIS OF THE STARTING AMINES OF FORMULA OD The amines were prepared as per the chemistry summarized in the Scheme-H and as per the methods disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33,2569-2578; C. Wang et. al., Tetrahedron, 1989, 45,1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO 24 95/25106 and WO 97,21708. Commercially available raw materials and known techniques were utilized for the synthesis. The optically pure amines as such were obtained by using optically active intermediates or resolution of racemic mixtures by a suitable reagent. The preferred enantiomer is (S), at the chiral centre on the oxazolidinone ring. Example 1 General Method for Preparation of the Amines (II) The oxazolidinone azides of general formula (8), given in Scheme-II (1.0 eq) were dissolved in dry THF (10 times by volume ) and treated with triphenyl phosphine (1.5 eq.) at room temp. The resulting solution was stirred for 6hrs at room temp. Water [2 eq. of (8)] was added and the solution heated for 6hrs at 55 - 60° C. The solvent was evaporated and the residue chromatographed on a column of silica gel (100 -200 mesh) and eluted initially with ethyl acetate and then with chloroform : methanol (4:1) to give the the amines (II) as white solids. The following amines i) to viii) of formula I were prepared by this general method, viz. i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vi) (S) - N -[3 - (3 - fluoro — 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, and viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine. SYNTHESIS OF THE STARTING CARBOXYLIC ACIDS OF FORMULA (HP Example 2 4-(2-Naphthyl)-4-oxobutanoic acid Naphthalene (5.0gm, 0.039moles) and succinic anhydride (4.68gm, 0.0468 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (11.44g, 0.0858 moles) was added at 25 room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 25 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid. Subsequent column chromatography gave a buff coloured solid. Subsequent chromatography gave 3.7 gm (41%) the title compound, mp 173-174° C. 'H NMR (CDCI3, 5) : 8.40 (s,lH), 7.7 - 8.0 ( m, 4H), 7.4 - 7.6 (m,2H), 3.33 (t,2H), 2.77 (t,2H + 1H). The filterate was concentrated to give 5.8 gm of a mixture of 4-(2-naphthyl)-4-oxobutanoic and 4-(l-naphthyl)-4-oxobutanoic acid. Example 3 4- Oxo-4-(2- ThienylJbutanoicacid Thiophene (5.0gm, 0.059moles) and succinic anhydride (7.13gm, 0.0713 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (17.43gm, 0.131 moles) was added at room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 30 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (50 ml). The solid was dried at room temp to give 9.8 gm (89%0 of the title compound, mp 103 - 107° C. !H NMR (CDCI3, 8) : 7.69 (dd, 1H), 7.58 (dd, 1H), 7.07 (dd,lH), 3.9 (bs, 1H), 3.23 (t, 2H), 2.74 (t,2H). Example 4 4- Oxo-4-(4-thiomethyl)phenylbutanoic acid Thiophenol methyl ether (8.0gm, 0.0645moles) and succinic anhydride (7.75gm, 0.0774 moles) were taken up in dichloroethane (80 ml). Aluminium chloride (18.90gm, 0.1419 moles) was added at room temperature. The resulting mixture stirred for 0.5hr and then heated at 85° C for lhr. The reaction mixture was cooled to room temperature, diluted with 40 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (80 ml). The solid was dried at room temp to give 6.9 gm (48%) of the title compound, mp 151 -154° C. H NMR (CDCI3, 5) : 7.82 (d,2H), 7.20 (d, 2H), 4.2 (bs, 1H), 3.21 (t, 2H), 2.73(t, 2H),2.45 (s,3H). 26 Example 5 4 - oxo -4- (2'methylpropyl)phenylbutanoic acid 2'methylpropylbenzene (5.0m, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles), were taken up in dichloroethane (50 ml). Aluminium chloride (10.90g, 0.0821 moles ) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 ml of a 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.7 gm (99%) of the title compound as a solid, mp 102 - 105° C. !H - NMR (CDC13, 8) : 7.83 (d,2H), 7.17(d,2H), 3.24(t,2H), 2.74(t, 2H), 2.46 (d, 2H), 1.80 (pent., 1H). Example 6 4 - Oxo - 4 - (2',2'dimethylethyl)phenylbutanoic acid 2',2'dimethylethylbenzene (5.0gm, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (10.90gm, 0.0821 moles) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 m of a 1:1 mixture of water Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.5 gm (97%) of the title compound as a solid, mp 103 — 107° C. !H-NMR (CDCI3,8) : 7.94(d,2H), 7.50 (d, 2H), 3.29 (t,2H), 2.82 (t,2H), 1.36 (s,9H). Example 7 Using the appropriate aromatic compound (Ar-H) and succinic anhydride and following exactly the method described in Examples 2-6 the following carboxylic acids can be prepared, viz. i) 4 -(4 -methylphenyl)- 4 - oxobutanoic acid, ii) 4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid, iii) 4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid, iv) 4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, v) 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, vi) 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid, vii) 4 -{2- Naphthyl)- 4 - oxobutanoic acid, viii) 4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, ix) (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and x) 4 - oxo - 4 - phenyl - but - 2 - ynoic acid. 27 SYNTHESIS OF THE COMPOUNDS OF FORMULA (D Example 7 Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - J - oxazolidinyl ] methyl] — 4-(4- naphthyl) -4- oxobutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 dichloromethane-water mixture (10 ml). To this was added 4 -( 2 - naphthyl- 4 - oxobutanoic acid (0.154gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) the resulting mixture was cooled to 0° C. l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added the resulting mixture was allowed to warm to room temperature and then stirred for 24hr. Saturated aqueous sodium bicarbonate solution (2ml) was added to the reaction mixture, stirred for 15 min and then the organic layer separated and the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.22 gm, 64%) as a white solid. MS (M+l) = 506 m/z H NMR (CDC13, 5) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, 1H ), 7.01(dd,lH ), 6.74 (t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, 1H), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91 (m,4H), 2.60(t, 2H). Example 8 Preparation of (S) -N-[[3- (3-fluoro-4-morpholinylphenyl) -2-oxo-5- oxazolidinyl ] methyl] -4- oxo -4-(2- thienyl)butanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml) . To this was added 4 - oxo - 4 (2 - thienyl)butanoic acid (0.125gm, 0. 00068 moles) and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the resulting mixture was allowed to warm to room temp and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated sodium bicarbonate was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separatedand the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.175 gm, 56%) as a white solid MS (M+1) = 462 m/z 28 lH NMR (CDC13, 8) : 7.63(d,lH ), 7.55 (dd,lH ), 7.35(dd,lH), 7.04(t, like dd, 2H), 6.83(t,lH), 6.30 (t,lH), 4.69(m,lH), 3.93 (t, 1H), 3.6- 3.8 (m, 3H),3.80 (m,4H), 3.61(dd, 2H), 3.21(dd,2H),2.97 (m,4H),2.55(t, 2H). Example 9 Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( V- methyl - 4 - propylphenyl) - 4 - oxobutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 -oxo - 5 -oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml). To this was added 4 - [ 4(2'-methylpropylphenyl)]- 4 - oxobutanoic acid (0.158gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated, and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.210gm, 60%) as a white solid. MS(M=l) = 512m/z 'H NMR (CDC13, 8) : 7.73(d,2H ), 7.52 (dd,lH ), 7.28(m,lH ),7.15(d,2H ), 7.05 (d,lH), 6.39 (t,lH), 4.75(m,lH), 3.91 (m, 4H), 3.5- 3.9 (m, 4H), 3.28 (dd, 2H), 3.16 (m,4H),2.54 (t, 2H), 2.45 (d, 2H), 1.82 (pent., 1H), 2.60 (t, 2H). Example 10 Preparation of(S) -N-[ [3 - (3 -fluoro -4- morpholinylphenyl) - 2 -oxo - J - oxazolidinyl J methyl J -4- oxo - 4 -(4- thiomethyl) phenylbutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF -water mixture (20 ml). To this was added 4 - (4-methlythiophenyl) - 4 - oxobutanoic acid (0.152g, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) and the resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142g, 0.00074 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate was added to, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The 29 combined fractions were concentrated to give the title compound (0.270 gm, 79%) as a white solid. MS (M+l) = 502 m/z JH NMR (CDC13, 5) : 7.70(d,2H ), 7.37 (dd,lH ), 7.14(d,2H ), 7.00 (dd,lH), 6.79(t,lH), 6.38 (t,lH), 4.71(m,lH), 3.86(t,lH),3.5- 3.9 (m, 4H), 3.81 (m, 4H), 3.22 (dd, 2H), 2.96 (m,4H),2.53 (t, 2H), 2.45(s,3H). Example 11 Preparation of:. (S) - N-[[3 - (3 -fluoro -4- morphottnylphenyl) — 2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) - 4 - oxobutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.100gm, 0.00034 moles) was taken up in 1:1 THF-water mixture (20 ml) . To this was added 4 - (4- chlorophenyl) - 4 - oxobutanoic acid(0.072g, 0.00034 moles and HOBt (0.046g, 0.00034 moles) .The resulting mixture was cooled to 0°C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.071gm, 0.00037 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated and 2 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with dichloromethane. The organic layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give (0.070gm, 42%) of the title compound as a white solid. MS (M+l) = 490 m/z JH NMR (CDCI3, 8) : 7.72(d,2H ),7.37 (dd,lH ),7.31(d,2H ), 6.98 (dd,lH),6.79 (t,lH), 6.28 (t,lH), 4.69(m,lH), 3.83 (t, 1H), 3.81 (m, 4H), 3.4- 3.m (m, 3H), 3.21 (dd, 2H), 2.97 (m,4H),2.54 (t,2H). Example 12 Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 -naphthyl) - 4 - oxobutanamide - N - oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (2 -naphthyl) - 4 - oxobutanamide (0.950gm, 0.0019 moles) in dichloromethane (150 ml) was added 60% m -CPBA (0.550g, 0.0032 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The column was eluted with ethyl acetate (200 ml), followed by a mixture of chloroform : methanol 30 (4:1,600 ml).Concentration the combined fractions gave the title N-oxide (0.891g, 82% ) as a white solid. !H NMR (CDCI3, 8) : 8.59(t,lH ), 8.36(s,lH),7.7-7.9 (m,5H), 7.2 -7.5 (m,2H),7.08 (dd,lH), 6.60(t,lH), 4.76(m,lH), 4.61(bt,2H), 3.5 - 4.3 (m, 9H), 3.42 (dd, 2H), 2.83 (bdd,2H), 2.61 (bt, 2H). Example 13 Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide. To a cooled solution (0 - 5° C) of (S) - N -[[3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - oxo - 4 - (2 - thienyl)butanamide (0.850gm, 0.0017moles) in dichloromethane (120 ml) was added 60% m -CPBA (0.550g,0.0032 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The column was eluted with ethyl acetate (200ml) followed by a mixture of chloroform : methanol (4:1,600 ml).Concentration of the combined fractions gave the tile N-oxide (0.790g, 90%) as a white solid. 1HNMR( CDCI3,5) : 8.63(t,lH), 7.77(dd,lH), 7.65 (d, 1H), 7.56 (d, 1H), 7.09 (dd, 1H),7.04 (dd,lH), 6.45(t,lH), 4.68(m,lH), 4.65(bt,2H), 4.22 (dt,2H), 3.89(t,lH), 3.5 - 3.9 (m, 5H), 3.22 (dd, 2H), 3.00 (bd,2H), 2.54 (t, 2H). Example 14 Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) -4- oxobutanamide -N- oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide, (1.150gm, 0.0023 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.725gm, 0.0040 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1,600 ml). Concentration of the combined fractions gave the title N-oxide (0.950g, 80%) as a white solid. 'HNMRtCDCk 8) : 8.61(t,lH ), 7.76(d,2H), 7.72 (dd, 1H), 7.34 (d, 2H), 7.10 (dd, 1H), 6.46(t,lH), 4.70(m,lH), 4.64(bt,2H), 4.16 (dt,2H), 3.94(t,lH), 3.5 - 3.9 (m, 5H), 3.24 (dd, 2H), 2.97 (bd,2H), 2.55 (t, 2H). 31 Example 15 Preparation of(S) -N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo -5-oxazolidinyl ] methyl] -4-/4-(2'- methyl - 4 -propylphenyl) -4 — oxobutanamide -N- oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - [4 - (2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide (1.05gm, 0.0020 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.600gm) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1 , 600 ml). Concentration of the combined fractions gave the title N-oxide (0.891gm, 82%) as a white solid. JH NMR (CDC13, 5) : 8.62(t,lH ), 7.77(dd,lH), 7.75 (d, 2H), 7.14 (d, 2H), 7.12 (dd, 1H), 6.44(t,lH), 4.75(m,lH), 4.64(bt,2H), 4.20 (dt,2H), 3.95(t,lH), 3.91 (t,lH) 3.5-3.9 (m, 4H), 3.26 (dd, 2H), 2.99(bd,2H), 2.57 (t, 2H),2.44(d,2H), 0.83(d,6H). Example 16 Preparation of (S)-N-ff3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4- methylphenyl)-4-thiooxobutanamide To a solution of (S)-n- of (S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4-methylphenyl)-4-oxo-butanamide (0.1 Ogm, 0.00021 moles) in dry THF (5ml) was added Lawessons Reagent (0.052gm, 0.000128 moles) and the resulting solution heated under reflux for 8 hr. The reaction mixture was cooled to room temperature and to this was added saturated aqueous sodium carbonate solution (3ml) and then extracted with ethyl acetate. The solvent was evaporated off and the residue chromatographed over silica gel and eluted with a mixture of ethyl acetate-hexane to give the title compound (0.023 gm, 23%) as a white solid, mp 149-151° C. lH NMR (CDCI3,5) : 8.60 (m, 1H), 7.68 (d, 2H), 7.34 (dd, 1H), 7.14 (d, 2H), 6.96 (dd, 1H), 6.81 (t, 1H), 4.90 (m, 1H), 4.20-4.40 (m, 1H), 3.80-4.0 (m, 4H), 3.50 (m, 2H), 2.90-3.00 (m, 6H). Example 17 Using the appropriate amine compound (II) and the carboxylic acid (HI) and following exactly the method described in Examples 7-16 the following carboxylic acids can be prepared, viz. (S) - N-[ [ 3 - (3-fluoro — 4- morpholinylphenyl) -2- oxo — 5- oxazolidinyl J methyl] — 4-(4- methylphenyl) -4- oxobutanamide. 32 'H NMR (CDCI3, 5) : 7.78 (d, 2H ), 7.44 ( d, IH ), 7.22 ( d,2H ), 7.09 ( d, IH ), 6.88 ( t, IH ), 6.41(t, IH), 4.76 (m, IH ), 3.6 - 4.1 (m, 4H ), 3.86 ( m, 4H ), 3.31 ( dd, 2H ), 2.61 (t, 2H ), 2.40 (s.3H). (S) -N-[[ 3-(3 -fluoro -4 - benzylpiperazinyl) phenyl] -2- oxo - 5 - oxazolidinyl] methy ] -4-oxo -4-phenylbutanamide. lH -NMR (CDC13, 5) : 7-88 ( d,2H ), 7.61 (dd, IH), 7.38 ( m, 5H ), 7.2 - 7.4 (m, 5H), 6.88 (t, IH ), 6.55 (t, IH ), 4.77 ( m, IH), 3.94 (t, IH), 3.5 - 3.7 (m, 3H ), 3.71 ( s, 2H ), 3.34 (dd, 2H ), 3.12 (m, 4H),3.12 (m, 4H ), 2.61 (t, 2H ). (S) - N-f]3 - ( 3 -fluoro - 4 - [methylbenzylamin]phenyl) - 2 - oxo -5 - oxazolidiny] methy ]-4-(4- methyl phenyl) -4- oxobutanamide. H NMR (CDCI3, 8) : 7.90 ( d, 2H ), 7.52 ( dd, IH ), 7.2 - 7.5 ( m, 8H ), 7.05 ( d, IH ), 6.84 (t, IH ), 6.50 (t, IH ), 4.75 (m, IH ), 4.48 (s, 2H ), 3.95 (t, IH), 3.6 - 4.1( m,3H ), 3.64 ( dd, 2H ), 2.71 (s,3H), 2.62 (t,2H). (S)-N-[[3-(3-fluoro-4- benzotriazolylpheny)-2-oxo-5-oxazolidinyl]methy]-4-oxo - 4 -phenylbutanamide. !H NMR ( CDCI3, 5) : 8.16 ( d,lH), 7.84 (d, 2H), 7.66 (t, IH), 7.2 -7.6 (m, 8H), 6.46 (t, IH ), 4.90 (m, IH), 3.98 (t,lH), 3.9 - 4.0 (m, 2H ), 3.65 (m, IH ), 3.39 (ddd, 2H ), 2.65 ( ddd, 2H). (S) -N-[[3-(3-fluoro-4- pyrrolidinylphen) -2-oxo-5- oxazolidinyl]methyl]-4-oxo - 4 -phenylbutanamide. !H NMR (CDCI3, 8) : 7.90 (d,2H ), 7.52 (dd, IH ), 7.44 (d, 2H ), (dd, IH ), 7.04 (dd, IH), 6.65 (t, IH), 6.43 (t, IH), 4.74 (m,lh), 3.93 (t,lH), 3.77 (t,lH), 3.6 3,8 (m, 2H), 3.33 (m, 6H ), 2.63 (t, 3H), 1.94 (m,4H). (S)-N-[[3-(3-fluoro-4- benzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methy]-4-(4- methlyphenyl) - 4- oxobutanamide. !HNMR (CDCU, 8) : 8.16 (d, IH ), 7.3 - 7.9( m,7H), 7.78 (d,2H ), 7.21(d,lH), 6.54(t, IH), 4.89 ( m, IH), 3.8 -42 (m, 3H ), 3.4 - 3.7 (m, 3H ), 2.63 (dd, 2H ), 2.23 (s, 3H ). (S)-N-][3-(3 -fluoro - 4 - thiomorpholinylphenyl) -2 — oxo - 5 - oxazolidinyl] methyl] -4- oxo- 4 -phenylbutanamide. !H NMR (CDCI3, 8) : 7.89 (d, 2H ), 7.39 - 7.60 ( m, 4H ), 7.11 (dd, IH ), 6.90 (t, IH), 6.39 ( t,lH ), 4.76 (m,lH ), 3.94 (t,lH ), 3.80 (t, IH ), 3.6 - 3.7 ( m, 2H ), 3.36 ( dd, 2H ), 3.28 ( m,4H), 2.80 ( m,4H ), 2.62 (t, 2H). (S) — N-[[3 - (3 -fluoro - 4 - benzylpiperazinyl) phenyl] — 2 — oxo — 5 - oxazolidinyl] methyl]- 4-(4- methylphenyl) -4- oxobutanamide. 33 H NMR (CDCI3, 5) : 7.81 ( d, 2H), 7.2 - 7.5 ( m, 8H ), 7.08 (dd, IH ), 6,89 (t, IH ), 6.39 (t, IH ), 4,78 ( m, IH ), 3.95( t, IH), 3.79 (t, IH), 3.6 - 3.7 (ni, 2H ), 3.61(s, 2H), 3.31 ( m,2H), 3.09 (m,4H), 2.65 (m,6H), 2.41 (s, 3H). (S)-N-[[3-(3-fluoro-4- piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl]-4- oxo - 4 - phenylbutanamide. !H NMR (CDCI3, 8) : 7.90(d,2H ),7.60 (dd,lH ),7.45(d,2H ), 7.39 (dd,lH), 7.10 (dd,lH), 6.90 (t,lH), 6.55 (t,lH), 4.78(m,lH), 3.95 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.35 (m, 2H), 3.00 (m,4H0,2.63 (t, 2H), 1.9-1.6 (m,6H). (S)-N-[[3- (3 -fluoro-4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4-(4 - methylphenyl) - 4- oxobutanamide. JH NMR (CDCI3, 5) : 7.79(d,2H ),7.40 (dd,lH ),7.23(d,2H ), 7.09 (dd,lH), 6.91 (t,lH), 6.40 (t,lH), 4.77(m,lH), 3.98 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.30(t, 2H), 2.98 (m,4H), 2.62 (t, 2H),2.41(s,3H), 1.6-1.9 (m,6H). (S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5- oxazolidinyl] methyl]- 4 -(4- methylphenyl) - 4- oxobutanamide. 'H NMR (CDCI3, 8) : 7.80(d,2H ),7.32 (dd,lH ),7.21(d,2H ), 7.01 (dd,lH), 6.60 (t,lH), 6.40 (t,lH), 4.75(m,lH),4.12(m,lH) 3.94 (t, IH), 3.75 (t, IH), 3.4- 3.6 (m, 2H), 3.34 (m, 6H), 2.61 (t, 2H),2.40(s,3H), 1.9(m,4H). (S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4 -(4- methoxyphenyl) -4- oxobutanamide. lU NMR (CDCI3, 8) : 7.79(d,2H ),7.36 (dd,lH ), 7.00 (dd,lH), 6.82 (d,2H), 6.80(t,lH), 6.38 (t,lH), 4.69(m,lH), 3.80 (s, 3H), 3.78 (m, 4H), 3.4- 4.0 (m, 4H), 3.20 (dt, 2H), 2.97 (m,4H),2.55 (dt,2H). (S) -N-[[3-(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4- (2 -naphthyl) -4- oxobutanamide. !H NMR (CDCI3, 8) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, IH ), 7.01(dd,lH ), 6.74 (t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, IH), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91 (m,4H), 2.60(t, 2H). ((S) - N -[[ 3 - (3 -fluoro -4- morpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4- (2, 4-difluorophenyl) -4-oxobutanamide. !H NMR (CDCI3, 8) : 7.73(ddd,2H ), 7.47 (dd,lH ), 7.01(dd,lH ),6.7 - 6.9(m,3H ), 6.30 (t,lH), 4.75(m,lH), 3.89 (m, 4H), 3.5- 3.9 (m, 4H), 3.20 (m, 2H), 3.09(m,4H), 2.52 (t, 2H). (S)-N -[[ 3-(3 -fluoro -4- morpholinylphenyl) -2- oxo -5— oxazolidinyl] methyl] - 4 -[4- (2s',2'- dimethyl- 4 - ethylphenyl) -4- oxobutanamide. 34 !H NMR (CDC13, 8) : 7.75(d,2H ), 7.37 (d,2H ), 7.35(dd,lH ), 7.05 (dd,lH), 6.82(t,lH), 6.37 (t,lH), 4.71(m,lH), 3.5- 3.9 (m, 4H), 3.80 (m, 4H), 3.25 (dt, 2H), 2.97 (m,4H),2.54 (t, 2H), 1.26(s,9H). (S) -N-ff 3 - (3 -fluoro - 4 -fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] -4-(4- methoxyphenyl) -4- oxobutanamide. lU NMR (CDC13, 8) : 7.76(d,2H ), 7.37 (dd,lH ), 7.16(m,5H ), 6.93 (dd,lH), 6.79(d,2H),6.74 ( t,lH), 6.37 (t,lH), 4.66(m,lH),4.14 (s,2H), 3.84(t,lH), 3.74 (s,3H), 3.4- 3.8 (m, 3H), 3.18 (dd, 2H), 2.62(s,3H),2.5 l(t, 2H). (S) -N-ff 3 - (3 -fluoro - 4 - fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl] methy] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide. 'H NMR (CDCU, 8) : 7.77(d,2H ), 7.37 (dd +d,3H ), 7.19 -7.22(m, 3H), 6.98 (dd,lH), 6.77(t,lH), 6.31 (t,lH), 4.69(m,lH), 4.17(s,2H), 3.89(t,lH)„3.72 (dd,lH), 3.5- 3.6 (m, 2H), 3.25 (dd, 2H), 2.64 (s,3H),2.55 (t, 2H), 1.25(s,9H). (S) -N-ff 3 -(3 -fluoro - 4 -[methylbenzylamino]phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] -4- (2,4 - dimethylphenyl) -4- oxobutanamide. lU NMR (CDCI3, 8) : 7.65(d,lH ), 7.46 (dd,lH ), 7.32(m,5H ), 7.04(m,3H), 6.95(t,lH), 6.36 (t,lH), 4.78(m,lH), 4.27(s,2H), 3.97(t,lH),3.6- 3.8 (m, 2H), 3.81 (t, IH), 3.27 (dd, 2H), 2.77 (s,3H),2.61 (t, 2H), 2.44(s,3H), 2.35 (s, 3H). (S)-N -[[ 3-(3 -fluoro -4- tnorpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] - 4 - (2,4 - dimethylphenyl) -4- oxobutanamide. 'H NMR (CDCU, 8) : 7.652(d,lH ), 7.42 (dd,lH ), 7.0- 7.1(m,3H), 6.86(t,lH), 6.38 (t,lH), 4.79(m,lH), 3.95(t,lH),3.5- 3.9 (m, 2H), 3.87 (m, 4H), 3.25(dd, 2H), 3.02 (m,4H), 2.59 (t, 2H), 2.41(s,3H), 2.34 (s, 3H). ^ -N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) —2 — oxo -5 — oxazolidinyl] methyl] — 4 — (2,4 - dimethylphenyl) - 4 - oxobutanamide. JH NMR (CDCI3, 8) : 7.62(d,lH ), 7.31 (dd,lH ), 7.03(s,+dd, 3H ), 6.60(t,lH), 6.36 (t,lH), 4.74(m,lH), 3.94(t,lH), 3.76 (dd, lH),3.67(m, 2H), 3.30 (m, 4H), 3.24 (dt, 2H), 2.60 (t, 2H), 2.44(s,3H), 2.34 (s, 3H).1.94 (m,2H). (S) -N-ff 3-(3-fluoro-4- benztriazolylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4- (2,4- dimethylphenyl) -4-oxobutanamide. !H NMR (CDCI3, 8) : 8.15(d,lH ), 7.80 (dd,lH ), 7.3 -7.7(m,6H ), 7.02(d,2H), 6.39 (t,lH), 4.87(m,lH), 4.07(t,lH), 3.96(t,lH), 3.89 (dq, IH), 3.75(dt,lH), 3.38 (qt, 2H), 2.62 (m, 2H), 2.39(s,3H), 2.26 (s, 3H). (S) - N-ff 3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4- oxo -4-(2- thienyl)butanamide. 35 H NMR (CDC13, 8) : 7.71(d,lH ), 7.63 (d,lH ), 7.31(dd,lH ), 7.11 (t, lH),7.05(dd,lH), 6.68(m,lH), 6.38 (t,lH), 4.74(m,lH), 3.95(t,lH), 3.77 (t, 1H),3.6- 3.7 (m, 2H), 3.36 (m, 4H), 3.28 (t, 2H), 2.63 (t, 2H), 1.96 (m,2H). (S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo - J - oxazolidinyl] methyl] - 4 - oxo -4-(2- thienyl)butanamide. !H NMR (CDC13, 8) : 8.08(d,lH), 7.77(dd,lH ), 7.3 - 7.7(m,7H ), 7.02(t,lH), 6.45 (t,lH), 4.81(m,lH), 4.00(t,lH),3.7- 4.0 (m, 2H), 3.57 (dt, 1H), 3.25 (m, 2H), 2.55 (m,2H). (3? -N-[[3-(3-fluoro-4- morpholinylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4- oxo - 4 -phenylbut - 2- enamide. JH NMR (CDCI3, 8) :7.92 (d,lH), 7.84 (,d,lH), 7.2 - 7.6 (m, 6H), 6.98 - 7.1 (m, 3H), 4.38(m, 1H), 3.5 - 4.1 (m, 4H), 3.84 (m, 4H), 3.03 (m, 4H). (S) -N-[[3-(3 -fluoro-4- piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4-(4 - methoxyphenyl) - 4- oxobutanamide. 'HNMR^MSOde, 8) : 8.25 (t, 1H), 7.79 (d, 2H), 7.38 (dd, 1H), 7.71 (dd, 1H), 6.95 (t,lH), 6.93 (d, 2H + 1H), 4.65 (m,lH), 3.75 (s,3H), 3.99 (t, 1H), 3.64 (dd, 1H), 3.06 (t, 2H), 2.81(m,4H), 1.3 -1.6(m.6H). (S) -N-[[3-(3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4 - chlorophenyl) - 4- oxobutanamide. lH NMR (CDCI3, 8) : 7.73(d,2H ), 7.33 (d,2H ), 7.2 - 7.8 (m, 2H),6.96(dd,lH), 6.34 (t,lH), 4.72(m,lH), 3.84(t,lH), 3.5- 3.8 (m, 3H), 3.21 (dd, 2H), 2.98 (m, 4H),2.54(t,2H), 1.5 - 1.7 (m,6H). (S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl] -4-(2,4 - dimethylphenyl) - 4- oxobutanamide. 'H NMR (CDCI3, 8) : 7.55(d,2H ), 7.4 (m,lH ), 6.9 - 7.0 (m, 3H),6.32(t,lH), 4.70(m,lH), 3.90(t,lH), 3.74 (t,lH), 3.5- 3.7 (m, 2H), 3.20 (dd, 2H), 2.9 - 3.1 (m, 4H),2.52(t,2H), 2.34 ( s,3H), 2.71 (s, 3H ), 1.5 -1.9 (m,6H). (S) - N-[[3 - (3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- methoxyphenyl) -4-oxobutanamide. XH NMR ( CDCI3, 8) : 8.07(d, 1H), 7.2 - 7.8 (m,6H), 7.71(d,2H ), 6.79 (d,2H ), 6.51(t,lH), 4.81(m,lH), 3.4- 4.0 (m, 4H), 3.71 (s, 3H), 3.15 (qt, 2H), 2.52 (dd, 2H). (S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- chlorophenyl) -4-oxobutanamide. 'H NMR (CDCI3, 8) : 8.09(d, 1H), 7.2 - 7.8 (m,6H), 7.75(d,2H ), 7.35 (d,2H ), 6.29(t,lH), 4.81(m,lH), 3.7 - 4.0(m, 3H), 3.5 - 3.7 (bt, 1H),3.25 (qt, 2H), 2.55 (t, 2H). (S)-N-[[3-(3-fluoro-4-(1,2,4-triazolyl)phenyl)-2-oxo-5- oxazolidinyljmethyl] -4- oxo — 4 - phenylbutanamide. 36 H NMR (CDCI3, 8) : 8.62 (bs, 1H ), 8.10 ( s, 1H ), 7.7 -7.8 ( m, 2H ),, 7.67 (dd, 2H, ), 7.44 (t, 1H ), 7.2 - 7.4 (m,3H ), 6.49 (t, 1H ), 4.78 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55 (dt, 1H ), 3.30 (ddd, 2H), 2.54 (dd, 2H). (S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4- methylphenyl) -4- oxobutanamide. XHNMR (CDC13, 8) : 8.71 (bs, 1H ), 8.10 ( s, 1H), 7.7 -7.9 ( m, 4H ), 7.30 (d, 1H, ), 7.21 (d, 2H ), 6.63 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.64(dt, 1H ), 3.35 (qdd, 2H), 2.5 - 2.6 (m, 2H), 2.35( s,3H). (S) - N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] - 4-(4- methoxyphenyl) -4- oxobutanamide. 'H NMR (CDCI3, 8) : 8.68 (bs, 1H ), 8.16 ( s, 1H ), 7.7 -7.9 ( m, 2H ), 7.79( d, 2H ) 7.28 (dd, 1H), 6.85 ( d,2H), 6.58 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.82(s,3H), 3.61(dt, 1H ), 3.32 (qdd, 2H), 2.65 (ddd, 2H). (S) -N-][3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl] -4-(2,4- dimethylphenyl) -4- oxobutanamide. !HNMR (CDCI3,8) : 8.69 (bs, 1H ), 8.17 ( s, 1H ), 7.78( t,lH), 7.75 ( d,lH ), 7.60 (d,lH),7.25(d, 1H, ), 7.10 (d, 1H ),6.99(s, 1H ), 6.54( t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.65(dt, 1H ), 3.25 (qt, 2H), 2.59 (dt, 2H), 2.38( s,3H), 2.29 (s,3H). (S) -N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4- oxo- 4 -(4 - thiomethylphenyl)butanamide. 'H NMR (CDCI3, 8) : 8.57 (bs, 1H ), 8.06 ( s, 1H ), 7.77 (m,2H), 7.61 (d, 2H), 7.19 ( d, 1H ), 7.10 (d, 2H, ), 6.47 (t, 1H ), 4.76 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25 (qdd, 2H), 2.55 (dq,2H),2.39(s,3H). (S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide. lU NMR (CDCI3, 8) : 8.58 (bs, 1H ), 8.06 ( s, 1H ), 7.80(t,lH),7.6 -7.8 ( m, 1H ), 7.67 (d, 2H,),7.32(d,2H), 7.26 (d, 1H ), 6.43 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25 (qt, 2H), 2.53(dt, 2H), 1.22( s,9H). (S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(2'- methyl - 4 - propylphenyl) -4- oxobutanamide. 'H NMR (CDCI3, 8) : 8.61 (bs, 1H ), 8.09 ( s, 1H ), 7.6 -7.8 ( m, 4H ), 7.24 (dd, 1H, ), 7.07 (d, 2H ), 6.38 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.54(dt, 1H ), 3.28(qt, 2H), 2.54(dt, 2H), 2.40( d,2H), 1.77 (pent.,lH), 0.81 (d,6H). (S) - N-[[ 3-(3 -fluoro -4- (1,2,4 — triazolyl) phenyl) -2- oxo -5— oxazolidinyl] methyl] -4-oxo - 4- (2- thienyl)butanamide. 37 'HNMR (CDCI3, 8) : 8.57 (bs, IH ), 8.05 ( s, IH ), 7.76 (t,lH),7.60(dd,lH), 7.53 (dd,lH), 7.25 (dd, IH, ), 7.01 (d, 2H ), 6.47( t, IH ), 4.78 ( m, IH), 3.7 - 4.0 (m, 3H), 3.56(ddd, IH ), 3.25 (qt, 2H), 2.54 (dt, 2H). (S) -N-[[3 -(3 -fluoro -4- (1,2,4-triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl]- 4 - (2-naphthyl) -4- oxobutanamide. !H NMR (CDCI3, 8) : 8.41 (s, IH ), 8.27( s, IH ), 8.02(s,lH), 7.3 -7.9 ( m,6H ), 7.3 - 7.6 (m, 3H), 6.44 (t, IH ), 4.77 ( m, IH), 3.7 - 4.0 (m, 3H), 3.2- 3.7 (m, 3H), 2.5-2.6 (m, 2H). (S) - N-[[3 - (3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4- chlorophenyl) -4- oxobutanamide. lH NMR (CDCI3, 8) : 8.58 (bs, IH ), 8.07 ( s, IH ), 7.6 -7.9 ( m, 2H ), 7.68 (d, 2H), 7.29 (d, 2H,), 7.2 - 7.3 (m, IH ), 6.31 (t, IH ), 4.81 ( m, IH), 3.7 - 4.1 (m, 3H), 3.55(dt, IH ), 3.25 (qt, 2H), 2.55(dt, 2H). (S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4- oxo -4-(2- thienyl)butanamide. H NMR (CDCI3, 8) : 7..5 - 7.7 ( m, 2H), 7.3 - 7.5 (m,lH), 6.8 - 7.3(m,3H ), 6.35(t,lH), 4.69(m,lH), 3.89 (t,lH), 3.76(t,lH),3.59(m,2H), 3.21(dd,2H),3.02 (m, 4H), 2.55 (t, 2H), 1.5 - 1.8 (m,6H). (S) -N-[[3 -(3-fluoro -4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4- (2'- methyl -4- propylphenyl) -4- oxobutanamide. 'H NMR (GDCI3,8) : 8.08 (m, IH ), 7.74 (d, 2H), 7.4 - 7.8 (m, IH ), 7.16 (d, 2H,), 6.97(dd,lH) 6.37 (t, IH ), 4.74 ( m, IH), 3.88 (t, IH), 3.80(t,lH), 3.4 - 3.71 (m, 2H), 3.40(m,4H) 3.25(dd, 2H ), 2.45(d, 2H), 1.80 (pent, IH), 1.5-1.8(m,6H),0.83(d,6H). (S)-N-[[3-(3-fluoro-4-piperidylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(4 - acetamidophenyl) -4- oxobutanamide. 'H NMR (DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.78 (d, 2H), 7.60 ( d, 2H), 7.36 (dd, IH), 7.06 (dd, IH), 6.93 (t,lH), 4.63 (m, IH), 3.95(t,lH), 3.61 (dd,lH), 3.07(dd,lH), 2.81 (m,4H), 1.99 (s, 3H), 1.55 (m, 4H), 1.44 (m, 2H). (S) - N-ff 3 -( 3 -fluoro - 4 * piperidylphenyl) - 2 - oxo - J - oxazolidinyl] methyl] -4- oxo - 4 -phenylbut - 2- enamide. JHNMR (CDCI3, 8) .-7.7-8.0 (m,3H), 7.2 - 7.6 (m, 5H), 7.01 (d,2H), 6.98 (t, IH), 4.80(m, IH), 4.01(t,lH), 3.85(t,lH), 3.77 (t, 2H), 3.16 (m, 4H), 1.5 - 1.9 (m,6H). (S) - N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] ~4- oxo- 4-(4- thiomethylphenyl)butanamide. lU NMR (CDCI3, 8) :7.70 (d,2H), 7.60 (bd,lH), 7.0 - 7.3 (m, 3H), 6.91 (d,lH), 6.47 (t, IH), 4.71(m, IH), 3.87(t,lH), 3.4 - 3.8 (m,3H ), 3.45(m, 4H) 3.21 (dd, 2H), 2.54 (t, 2H), 2.45 (s,3H), 2.06(m,4H). 38 (S)-N-[[3-(3-fluoro-4-pyrrolidinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(2-naphthyl) -4- oxobutanamide. !H NMR (CDC13, 8) : 8.35 (s, IH ), 7.5 - 8.1 (m, 8H ), 6.91(d,lH) 6.53 (t, IH ), 4.72 ( m, IH), 3.38 (m, 4H), 3.2 - 4.0 (m, 6H), 2.61(m, 2H), 1.99 (m,4H). (S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] — 4 — (2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide. lU NMR (CDCI3, 8) :7.75 (d,2H), 7.46 (m,lH), 7.1 - 7.3 (m, 3H), 6.95 (d,lH), 6.44 (t, IH), 4.70(m, IH), 3.3 - 4.0 (m,4H ), 3.41(m, 4H) 3.24 (dd, 2H), 2.55 (t, 2H), 2.45 (d,2H), 2.01(m,4H), 1.81 (pent,lH), 0.83 (d, 6H). (S) -N-][3-(3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4- (2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide. lH NMR (CDCI3, 8) :7.76 (d,2H), 7.2 7.5(m, 4H), 6.95 (d,lH), 6.33 (t, IH), 4.69(m, IH), 3.88(t,lH), 3.71(t,lH), 3.6 - 3.7 (m,2H ), 3.45(m, 4H) 3.23 (dd, 2H), 2.56 (t, 2H), 1.94 (m,4H), 1.26(s,9H). (S^J - N-[[3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4 — (4 - acetamidophenyl) -4- oxobutanamide. 'H NMR (CDCU, 8) : 7.2 - 7.8 (m, 7H), 6.85 (d,lH), 6.47 (t, IH), 4.67(m, IH), 3.81(t,lH), 3.3 - 3.7 (m,3H ), 3.46(m, 4H) 3.16 (m, 2H), 2.3 - 2.9 (m,6H), 2.06(s,3H). (Sp -N-[]3-(3-fluoro -4- pyrrolidinylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4- oxo - 4 -phenylbut - 2- enamide. 'HNMR (CDCI3, 8) :7.8 - 7.9 (m,3H), 7.0 - 7.6 (m, 5H), 6.93 (d,lH), 6.75 (m,lH), 4.76(m, IH), 4.02(t,lH), 3.74 (m, 3H), 3.30 (m, 4H), 1.95 (m,4H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]- 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. !HNMR (CDCI3, 8) :7.78 (d,2H), 7.33 (dd,lH),6.99 (d,lH), 6.83 (t,lH), 6.81 (d, 1H),6.38 (t, IH) 4.69(m, IH), 3.86 (t,lH), 3.79 (s,3H), 3.5 - 3.8 (m,3H ), 3.41(m, 4H) 3.20 (m, 6H), 2.73(m,4H) 2.53 (t, 2H). (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5- oxazolidinyl]methyl]- 4 - (2,4 - dimethylphenyl) -4- oxobutanamide. !H NMR (CDCI3, 8) :7.55 (d,lH), 7.33 (dd,lH), 6.96 (m,3H), 6.81(t,lH), 6.22 (t, IH), 4.69(m, IH), 3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.17(m, 6H) 2.73 (t, 2H), 2.45 (d,2H),2.51 (t,2H), 2.34(s,3H), 2.27 (s,3H). (Si)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]- 4 - oxo -4-(2- thienyl)butanamide. !H NMR (CDCI3, 8) :7.63 (d,lH), 7.55 (d,lH), 7.33 (dd, IH), 7.05 (dd,2H), 6.85(t, IH), 6.31 (t,lH), 4.69(m, lH),3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.23(m, 6H) 2.73 (m, 4H), 2.55 (t, 2H). 39 (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - J - oxazolidinyl] methyl] -4-(4- acetamidophenyl) -4- oxobutanamide. 'HNMR ( DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.73(d, 2H), 7.59 (d, 2H), 7.38 ( dd, IH), 7.08(dd,lH), 6.99 (t, IH), 4.65 (m, IH), 3.95(t,lH),3.62(dd,lH), 3.08(m, 6H), 2.66 (m, 4H), 1.97 (s,3H). (S) - N -[[ 3 - (3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] - 4 -oxo - 4 - (4 - thiomethylphenyl)butanamide. •HNMR (CDC13,8) : 7.70 (d, 2H), 7.32 (dd,lH),7.14 (d, 2H,), 6.99(dd,lH), 6.82(t,lH), 6.33 (t, IH ), 4.68 ( m, IH), 3.86 (t, IH), 3.4 - 3.8 (m, 3H), 3.20(dt, 2H ), 2.90(t,4H) 2.53(t, 2H), 2.44(s,3H), 1.67 (m,4H), 1.5 (m,2H). (S) -N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl] -4-(naphthyl) -4- oxobutanamide. 'H - NMR ( CDCI3) : 8.36 (s, IH ), 7.7 - 7.9 (m, 4H, ), 7.4 - 7.6 (m, 2H ), 7.32 (dd,lH), 6.99(d,lH), 6.78(t,lH), 6.43 (t, IH), 4.70 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.39(dt,2H), 2.86(t,4H), 2.61(t, 2H), 2.10(m,4H),1.50 (m,2H). S) -N-[[ 3- (3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide. lUNMR (CDCI3,8) : 7.75 (d, 2H), 7.37 (d,2H),7.31 (dd, IH, ), 7.00(dd,lH), 6.84(t,lH), 6.37 (t, IH ), 4.68 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.25(dt, 2H ), 2.91(t,4H) 2.54(t, 2H), 2.23(m,4H), 1.5 (m,2H), 1.26(s,9H). (S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4-oxo -4-(4- thiomethylphenyl)butanamide. 'HNMR (CDCI3, 8) : 8.08 (d, 2H ), 7.77 (dd, IH, ), 7.63(d,2H), 7.2 - 7.5 (m, 4H ), 7.12 (d,2H), 6.41 (t, IH ), 4.81 ( m, IH), 3.98 (t, IH), 3.7 - 3.9 (m, 2H), 3.54(dt,lH), 3.22(qdd,2H), 2.54(dd, 2H), 2.36(s,3H). (S) -N-[] 3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5 - oxazolidiny] methyl] -4-(2-naphthyl) -4- oxobutanamide. 'HNMR (CDCI3, 8) : 8.35( s,lH), 8.08 (d, IH ), 7.6 - 7.8(tn,5H), 7.2 - 7.6 (m, 7H ), 6.41 (t, IH ), 4.82 ( m, IH), 3.8 - 4.0 (m, 3H), 3.3 - 3.7(m,3H), 2.64(dd, 2H). (S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4 - (2',2' - dimethyl- 4 - ethylphenyl) -4- oxobutanamide. H NMR (CDCI3, 8) : 8.08 (d, IH ), 7.80 (dd, IH, ), 7.70(d,2H), 7.57(t, IH), 7.2 - 7.5 (m, 4H ), 7.08 (d,2H), 6.41 ( t, IH ), 4.80 ( m, IH), 3.7 - 4.0 (m, 3H), 3.55(dt,lH), 3.1 - 3.4(m,2H), 2.54(dd, 2H), 2.37(d,2H), 1.72(pent,lH), 0.76(d,6H). 40 (S)-N-[[3-(3-Jluoro-4- henzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide. JHNMR(CDC13, 5) :7.2 - 8.0 (m,13H), 6.95 (d,lH), 6.65 (m,lH), 4.89(m, IH), 4.18(t,lH), 3.7-4.0 (m, 3H). (S) -N-[[3-(3-Jluoro-4-benztriazolylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 -(4- acetamidophenyl) -4- oxobutanamide. !HNMR (DMSOde, 8) : 10.16 (s, IH), 8.29(t, IH), 8.12 (d, IH), 7.79 (m, 4H), 7.58 ( d, 2H), 7.4 - 7.5 (m, 4H), 4.74 (m, IH), 4.13(t,lH),3.08(dd,lH), 3.10 (t, 2H), 1.97 (s, 3H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide. lH NMR (CDCI3,8) : 7.76 (d, 2H), 7.53 (dd, 1H),7.39 (d, 2H +1H, ), 7.02(d,lH), 6.29 (t, IH ), 4.71 ( m, IH), 3.89 (t, IH), 3.79(t,lH), 3.5 - 3.7 (m, 2H), 3.38(m, 4H ), 3.24 (dd,2H), 2.92(m,4H) 2.54(t, 2H), 1.26(s,9H). (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide. JH NMR (CDCU, 8) :7.8 - 7.9 (m,3H), 7.3 - 7.7 (m, 5H), 6.8 -7.0 (m,3H), 4.81(m, IH), 4.05(m,lH), 3.75 (m, 3H), 3.49 (m, 4H), 3.10 (m,4H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(fi- naphthyl) -4- oxobutanamide. !H NMR (CDCI3, 8) : 8.35 (s, IH), 7.7-8.0 (m, 4H), 7.3-7.7 (m, 5H), 7.01 (m, IH), 6.48 (m, IH), 4.74 (m, IH), 3.80 (m, 3H), 3.60 (m, IH), 3.37 (m, 6H), 2.93 (m, 4H), 2.60 (m, 2H) (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4- (4- chlorophenyl) -4-oxobutanamide. !H NMR (CDCI3, 8) : 7.74 (d, 2H), 7.54 (d, IH), 7.34 (d, 2H+1H), 6.98 (d, IH), 6.35 (t, IH), 4.78 (m, IH), 3.88 (t, IH), 3.5-3.8 (m, 3H), 3.38 (m, 4H), 3.22 (dd, 2H), 2.93 (m, 4H), 2.54 (t, 2H). (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4 - (2,4 - dimethyl- 4 ethylphenyl) -4- oxobutanamide. lH NMR (CDCI3, 8) : 7.95 (m, IH), 7.74 (d, 2H+1H), 7.77 (d, 2H), 7.07 (d, IH), 6.38 (t, IH), 4.76 (m, IH), 3.91 (t,lH), 3.4-3.8 (m, 3H), 3.58 (m,4H), 3.25 (dd, 2H), 3.1 (m, 4H), 2.54 (t, 2H), 2.46 (d, 2H), 1.80 (pent, IH), 0.85 (s, 3H), 0.82 (s, 3H). Microbiology: Pharmacological testing The compound of formula (I) of the present invention displayed antimycobacterial activity when tested by in vitro growth inhibition assay and agar incorporation methods. The minimum inhibitory concentrations (jag/ml) obtained for representative compounds of formula (I) 41 against M. tuberculosis including sensitive and resistant strains are summarized in Table-I. The MIC value of a representative preferred Compound No. 30 of formula I against different species of mycobacteria is summarized in Table-II. in vitro Growth Inhibition assay The ability of the compounds 1-78 of formula (I) of this invention to inhibit the growth of Mycobacterium species was determined by the BACTEC 460 TB system. The reference strain M tuberculosis H37Rv ATCC 27294 was grown in Middlebrook 7H9 broth containing 10% ADC supplement at 37°C on a rotay shaker at 150 rpm for grown for 7days. The turbidity of the culture was adjusted to 1.0 Mc farland. The BACTEC 7H12B medium vials were seeded with 0.1ml of the 1.0 Mc farland adjusted M. tuberculosis culture. In the control vials 0.1ml of the culture was added after lOOfold dilution of the initial inoculum. Stock solution of lmg/ml of each compound was prepared in DMSO in separate sterile tubes. The compounds were further diluted to concentration of 25 ^g/100 ul, 0.1ml was than added to the 7H12B vial containing mycobacterial culture so that final concentration of the compound 6.25 u.g/ml. The cap in all the vials were cleaned with isopropanyl alcohol and kept in racks. The vials were then incubated at 37°C without shaking. Test vials was read daily on the BACTEC system till the GI of the control vial reached > 30.Once the GI in the control reached 30 AGI (GI = GI (n> - GI („.i) ) was determined for all test and control vials. If AGI of test vial is less than that of the control vial the culture was sensitive to the test compound. in vitro Agar Dilution assay MIC of compound of formula (I) of this invention against strains of Mycobacterium were determined by a reference agar dilution method as per the NCCLS- M24-T2. recommendations. The compounds were dissolved in DMSO and diluted twofold to obtain ten serial dilutions of each compound. Appropriate volume of compounds were incorporated into duplicate plates of Middlebrook7H10 agar medium supplemented with 10% Middlebrook supplement oleic acid-albumin-dextrose (OADC) enrichment at concentration of 0.03u,g/ml to 16\|j,g/ml. Test organisms (mycobacterium strains) were grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement. After 7 days of incubation at 37°C the broths were adjusted to the turbidity of 1.0 McFarland standard; the organism were further diluted 10 fold in sterile water containing 0.10% Tween-80. The resulting mycobacterial suspensions were spotted (3-5jxl/spot) onto drug supplemented 7H10 media plates. The plates were sealed and incubated at 37°Cfor 3-4 weeks in upright position. The MIC was recorded as the lowest dilution of the drug that completely inhibited the growth of test organisms. Test isolates included 10 clinical isolates that were generally susceptible to common tubercular agents and 10 strains that were resistant to one or more standard anti tubercular drugs. Appropriate reference strains and control drug was included in each batch of test. 42 in vivo studies: The efficacy of the compound of formula (I) of this invention was also evaluated in murine model of pulmonary tuberculosis. Mycobacterium tuberculosis cultures grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement at 37°C for 7 days on a rotary shaker. For, animal inoculation liquid cultures were declumped by brief sonication and were diluted appropriately in 7H9 broth to obtain a concentration of lxl07CFU's/ 0.2ml. Four-week-old male outbred Swiss albino mice housed in a pathogen free, biosafety level 3 environment within micro isolator cages were used throughout the study. Infections were produced by intravenous inoculation into caudal tail vein of 0.2ml of declumped M. tuberculosis suspension. Following infection, mice were randomly distributed in different groups of six each. Treatment for initial study was started one day after infection. For, treatment Compound No. 30 of formula I was dissolved in 10% PEG. Isoniazid was dissolved in sterile water. The drugs were prepared each morning prior to administration. Therapy was given 5 days per week for four weeks. All the agents were administered by gavage and were dosed at 50,25,12.5mg / kg of body weight. Control group of infected but untreated mice were killed at the initiation of therapy (early control) or at the end of the treatment period (late control). Mice were sacrificed by cervical dislocation 3-5 days after the administration of the last dose of drug. The spleens and right lung were removed aseptically and homogenized in tissue homogeniser. At least 4 serial tenfold dilution of the homogenate was plated onto selective Middlebrook 7H11 agar plates in duplicate. The colony counts were recorded after incubation at 37°C for 4 weeks. The viable cell counts were converted to Logio values. A compound showing 2 Log reduction in viable counts compared to the controls was considered significant. The in vivo data for a representative compound of formula (I) is given in Table-II. Acute toxicity of Compound No. 30 of Chart-I was estimated in mice and the LDo was found to be >1000 mg/kg P. O. 43 Table-I: in vitro activity of compounds 1 to 58 of formula (I), Compound No. Growth inhibition of M.tuberculosis 27294 MIC (fig/ml) against M.tuberculosis 27294 Clinical isolates Sensitive Resistant 1 + 16 4-16 >16 2 + 8 8 8 8 + 2 .5-2 2-4 13 + 2 2 2-4 14 + 0.25 0.25-0.5 4->16 15 + >16 >16 >16 16 + 0.5 0.5 0.5(>16) 17 + 0.5 1.0 0.5-1.0 18 + 4- 1-4 8->16 19 + 2 1-2 2 20 + 1 1-2 2-4 21 + 0.5 0.5-2 0.5(>16) 25 + 4 4-16 4->16 27 + >16 >16 >16 28 + 0.5 1-2 2-8 30 + 0.5 0.5 0.5-2 31 + 1 1-2 1-4 32 + 0.25 0.25-0.5 4-(>16) 33 + 0.5 1 0.5-2 34 + >16 >16 >16 35 + 4 2-4 4-8 36 + 4 4-8 4-8 44 Table-I Contd.... 39 + 2 2-4 2-8 40 + 1 1-2 1-2 43 + 1 0.5-1.0 1-2 44 + 1 0.5-2 1-4 45 . + 2.0 2-4 2-4 46 + 2 2-4 2-8 47 + 1 1-2 2-4 48 + 2 2-4 2-8 49 + 4 4-16 4-16 50 + 2 2-4 2-4 51 + 8 8->16 8->16 52 + 2 2 4->16 53 + >16 >16 >16 54 + 8 8-16 >16 55 + >16 >16 >16 56 + >16 >16 >16 57 + 16 16->16 >16 58 + 8 8-> 16 8-> 16 Isoniazid + 0.25 0.12- .25 8 - >16 Linezolid + 0.5 0.25-0.5 1.0-2.0 Table-II MIC values of compound of formula (I) against different species ofMycobacteria Sr. No. Compound No. MIC (ug/ml) M. tuberculosis M.avium- intracellular complex M.fortuitum M.kansai Sensitive Resistant 1 Compound 30 of formula I 0.50 0.50-2.0 8.0->16.0 >16.0 8.0 2 Isoniazid 0.25 4.0-> 16.0 8.0->16.0 >16.0 >16.0 45 Table-m in vivo activity of Compound of formula (I) against M. tuberculosis ATCC 27294" infection in Swiss albino mice Sr. No. Drug& Dose b (mg/kgday" ') or group Mean Logio No. of CFU Mean Logio No. of reductionc Lung Spleen Lung Spleen 1 Compound 30 of Chart-I 50mg/kg 25mg/kg 12.5mg/kg 2.12 2.21 4.34 2.09 2.13 4.30 2.40 2.30 0.20 2.53 2.49 0.26 2 Isoniazid 50mg/kg 25mg/kg 12.5mg/kg 2.03 2.11 2.95 1.92 2.11 2.94 2.49 2.41 1.57 2.70 2.51 1.68 3 Infected early control 4.52 4.62 4 Infected late control 6.57 6.37 a- inoculation of logio:- 7.00 Mycobacteria. b- mice were dosed 5 day/week for 4 weeks. From day 1 -28. c- difference in mean logio number CFU from that of early controls. The compound of formula I of this invention may be administrated to a subject such as a human being or an animal in need of such an administration through any route appropriate to the condition to be treatede. Suitable routes of administration include oral, rectal, nasal, topical (both buccal and sublingual), vaginal and parenteral (including subcutaneous, intramuscular, intradermal, intrathecal and epidural). Pharmaceutical compositions of compound of formula I can be prepared in adjunction with inert pharmaceutically acceptable carriers, which can either be solid or liquid. Solid form preparations include powders, tablets, dispersible granules, capsules, cachets, suppositories and ointments. The solid carriers can be one or more substances which may act also as diluents, flavouring agents, solubilisers, lubricants, suspending agents, binders or tablet disintegrating agents. It can also be finely divided solid which is in admixture with finely divided active compound. Suitable solid carriers are lactose, pectin, dicalcium phosphate, microcrystalline cellulose, sucrose, kaolin, dextrin, gelatin, starch, tragacanth, low melting wax, coca butter and the like. Liquid preparations include solutions, suspensions and emulsions, e.g. solutions of compound of formula I in water or water-propylene glycol mixture for parenteral injection. Liquid preparations can also be formulated along with non-ionic surfactants and edible oils such as corn, peanut and sesame oils. Aqueous solutions for oral use can be prepared by dissolving the active component in water and adding suitable colorants, flavours stabilizing and thickening 46 agents, as required. Aqueous suspension for oral use can be made by dispersing the finely divided active component in water with a viscous material, e.g. natural or synthetic gums, resins, methyl cellulose, sodium carboxymethyl cellulose and othe known suspending agents. The adjuvants may also include preserving agents and anti-oxidants. Compositions for topical application may take the form of liquids or gels, containing a therapeutically effective concentration of compound of formula I admixed with a dermatologically acceptable carrier. The pharmaceutical preparations may be in unit dosage form. In such form, the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage can be in the form of tablets, capsules, powdersin vials or ampoules, ointments, gels, creams or any other form. The quantity or concentration of the active compound in such unit dose preparations may be varied or adjusted according to the particular application and potency of the active ingredient. 47 A compound of formula (I) and its pharmaceutical^ acceptable salts wherein, A is either hydrogen or fluorine, B is either hydrogen or fluorine, A and B together is hydrogen and fluorine, Ri is a group of formula, wherein, Q is either an alkyl group of two carbon atoms, an alkene group of two carbon atoms or an alkyne group of two carbon atoms Y is oxygen, sulfur or an amino function of formula NR3 wherein, R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or branched; cycloalkyl of 3-7 carbon atoms; CHO, -COOH, -COOR,; COCR,; CN; aryl or heteroaryl wherein, Rt is an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms. Ar is a substituted phenyl ring or a substituted pyridine ring of formula —O-R3 or Ar is a five membered ring of formula 48 or Ar is a fused bicyclic phenyl or pyridine ring of formula wherein, M is either CH or N Z is CH, NH, O, or S, X is a group selected from OR,, NR4R5, N02, SR,, SOOR,, SOONR4R5, F, CI, Br or I, wherein R4 is as defined hereinbefore, and and R3 is as defined hereinbefore R5 is hydrogen or R4 R2 is selected from the groups shown below, and the corresponding N-oxides thereof. A compound according to Claim 1 wherein in said compound of formula I Aryl is phenyl substituted with (0) or (1) of F, CI, "OCH3, "OH, "NH2, CrC4 alkyl, 0-C(0)-OCH3," N02or"CN. 49 3. A compound according to Claim 1 wherein said compound of formula I is selected from the group consisting of: 1) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 2) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 3) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 4) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide. 5) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 6) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 7) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide. 8) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 9) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 10) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 11) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide. 12) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide. 13)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 14) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide. 15) (S) - N -[ [ 3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide. 16) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl 1 methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide. 17) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 50 18) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 19) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl]-4-oxo-4-(2-thienyl)butanamide. 20) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 21)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide. 22) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 23) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 24) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 25) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 26) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) — 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 27) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 28) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide. 29) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide. 30) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide. 31)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (2 - thienyl)butanamide - N - oxide. 32) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide. 33) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N -oxide. 34) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 51 35) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4- oxobutanamide. 36) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4- oxobutanamide. 37) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4- oxobutanamide. 38) (S) - N -[ [ 3 - (3 - fluoro - 4 - benztriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 39) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 40) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 41) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4 - oxobutanamide. 42) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 43) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 44) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide. 45) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 46) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 47) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide. 48) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide. 49) (S) - N .-[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 50) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 51) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 52) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide. 52 53) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 54) (S) -N-[[3-(3- fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 55) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 56) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -■ ( 4 - thiomethylphenyl )butanamide. 57) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2 - naplrthyl) - 4 - oxobutanamide. 58) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide. 59) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 60) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 61)(S)-N-[[3-(3- fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 62) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 63) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 64) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide. 65) (S) - N -[ [ 3 - ( 5 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 66) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (4 - thiomethylphenyl)butanamide. 67) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 68) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 69) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide. 70) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 53 71) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 72) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 73) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 74) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 75) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 76) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) --2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2 - naphthyl) - 4 - oxobutanamide. 77) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - '2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 78) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide. - ' 4. A compound as claimed in claim 3 wherein said compound of formula I is selected from the group of N-oxide of the said compounds 1 to 78. 5. A pharmaceutical composition comprising a) atleast one of I) any compound of claims 1 to 4 and II) its pharmaceutically acceptable salts and b) a pharmaceutically acceptable carrier. 6. A pharmaceutical composition according to claim 5 comprising a solid or liquid preparation. 7. A pharmaceutical composition as claimed in anyone of claims 5 to 6 for oral or parenteral administration. 8. A method of preparation of the compound of formula I and/or its pharmaceutically acceptable salts comprising: coupling of the amino fragment of compound of formula II 5^ (II) with a carboxylic acid of formula III in the presence of an acid activating group or a dehydrating agent in a suitable solvent. (Ill) wherein R2 has the same meaning as given in claim 1. 9. A method as claimed in claim 8 wherein the compound of formula II is preferably selected from (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine,(S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, S) - N -[3 - (3 - fluoro - A - benzotriazolylphenyl) - 2 - oxo - 5 -oxazolidinyl] methyl amine, and (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine. 10. A method as claimed in anyone of claims 8 or 9 wherein the compound of formula III is selected from 4-(2-Naphthyl)-4-oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic acid, 4-oxo-4-(2' methy lpropyl)phenylbutanoic acid, 4-Oxo-4-(2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 - 5S oxobutanoic acid,4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, . 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 - phenyl - but - 2 - ynoic acid. 11. A compound of formula I, its pharmaceutically acceptable salts and pharmaceutical compositions obtained thereof substantially as herein described and illustrated. Dated this 5th day of March 2005 Dr. Sanchita Ganguli Of S. MAJUMDAR & CO. Applicants' Agent 5t F0RM2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See section 10; rule 13) 1. Title of the invention. - OXAZOLIDINONE DERIVATIVES, PROCESS FOR THEIR PREPARATION AND THEIR USE AS ANTIMYCOBACTERIAL AGENTS 2. Applicants) (a) NAME : LUPIN LIMITED (b) NATIONALITY : An Indian Company (c) ADDRESS : 159, C.S.T. Road, Kalina, Santacruz (East), Mumbai - 400 098, Maharashtra, India 3. PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed FIELD OF THE INVENTION The present invention relates to novel compounds belonging to the class of oxazolidinones useful in the treatment of acid fast organisms such as Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium spp. The present invention further relates to methods for preparation of the novel compounds and to pharmaceutical compositions containing the novel compounds useful in the treatment of tuberculosis. BACKGROUND OF THE INVENTION Tuberculosis (TB), an infectious disease caused by the bacterium Mycobacterium tuberculosis is transmitted mainly through air, affecting most often the lungs. When persons with pulmonary TB cough they produce tiny droplet nuclei containing M. tuberculosis, which remain suspended in air for a prolonged period of time. A person who breathes the air containing the aforesaid droplet nuclei containing M. tuberculosis can become infected with TB. TB, one of the three major infectious diseases in the priority list of the World Health Organization's (WHO) agenda kills about two million people around the world every year. About six million new cases are reported every year and nearly 20% of adult deaths and 6% of infant deaths are attributable to the disease (C. Dye et. al., J. Am. Med. Ass., 1999, 282, 677-686). About a billion people are expected to be affected by TB by the year 2020, with 35 million likely to succumb to the disease (WHO Fact Sheet No. 104, Global Alliance for TB Drug Development- Executive Summary of the Scientific Blueprint for TB Development : http://www.who.int/inf-fs/en/factl04.html). With the emergence of the AIDS epidemic and the increase in cases of HIV coupled with TB as well as the continued resistance of M. tuberculosis to isoniazid and rifampicin, the two most powerful anti-tubercular drugs available today there is an urgent need for new anti-tubercular drugs to combat the killer disease (S. H. E. Kaufmann et. al., Trends Microbiol., 1993, 1,2-5 ; B. R. Bloom et. al., N. Engl. J. Med., 1998, 338, 677-678). Although, many new compounds are becoming available for fighting a number of infectious diseases, the number of such compounds having antimycobacterial activity are few. This could partly be due to the complexity of research involved and partly due to business considerations (B. N. Roy et. al., J. Ind. Chem. Soc, April 2002, 79, 320-335 and references cited therein). However, renewed thrust in research in the last decade has resulted in development of new antimycobacterial compounds, a) differing widely in structures, b) having different mode/mechanism of action, c) possessing favourable pharmacokinetic properties, d) which are safe and have low incidence of side-effects, and e) which provide a cost-effective dosage regimen. 2 Among the aforesaid new compounds, the oxazolidinones first developed during the mid-1980s (W. A. Gregory et. al., J. Med. Chem., 1989, 32,1673-1681 and 1990,33,2569-2578 ; C-H Park et. al., J. Med. Chem., 1992, 35, 1156-1165) are a unique class in themselves. The in vivo results for some of the oxazolidinones show that they are active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, including resistant strains such as methicillin-resistant Staphylococcus aureus [MRSA], methicillin-resistant Streptococcus epidermidis [MRSE], penicillin-resistant Streptococcus pneumoniae [PRSP], vancomycin-resistant enterococci [VRE], etc. (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999,9 (5), 625-633 and the references contained therein). The oxazolidinones inhibit bacterial protein synthesis at a very early step in the initiation of complex formation involved in the process of translating mRNA into protein. The oxazolidinones, in general, are not cross-resistant with any known antibiotic because of this unique mechanism (D. C. Eustice et. al., Antimicrob. Agents Chemother., 1988, 32, 1218 and Biochem. Biophys. Res. Commun., 1988,150. 965). A feature of the oxazolidinone molecule is that only those compounds, which are enantiomers with a (5S)-acetamidomethyl configuration in the left side of the molecule are known to exhibit antibacterial activity (W. A. Gregory et. al., J. Med. Chem., 1989, 32, 1673-1681). Another feature is that most of such antibacterial compounds invariably carry a (substituted) phenyl ring attached to the nitrogen atom of the oxazolidinone ring in the right side of the molecule (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999, 9 (5), 625-633 and the references contained therein). The most promising compound among the N-phenyl oxazolidinones, which has been approved for human use is (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidin-yl]methyl]-acetamide), commonly known as linezolid (M. Barbachyn et. al., WO 995/07271). Linezolid possesses good in vitro and in vivo potency against most of the Gram-positive bacteria, including resistant strains {Drugs of the Future, 1996,21.(11), 1116-1123). The left hand side i. e. position 5- and the right hand side i. e. position 3- respectively of the oxazolidinone ring nucleus allows for many variations and has resulted in the discovery of a large number of compounds having antimicrobial and antibacterial properties. Such representative compounds, albeit not meant to be limiting are disclosed in the following prior art references. These are: i) US 4,942,183 (Gregory et. al.) and US 4,948,801 (Carlson et. al.) collectively disclose certain 3-substituted phenyl- 5-aminomethyl oxazolidinones, possessing useful antibacterial activity, ii) US 5,529,998 (Habich et. al.) discloses certain 3-benzoxazoyl- and benzothiazolyl-5- acetyl amino methyl oxazolidinones, useful as antibacterial medicaments. 3 iii) US 5,565,571, US 5,654,428, US 5,756,732, US 5,801,246 and US 5,929,248 (Barbachyn et. al.) collectively disclose several substituted aryl and heteroaryl phenyloxazolidinones carrying an acetyl aminomethyl function at the 5-position, specifically oxazolidinones having an aryl or heteroaryl group at the para position of the 3-phenyl ring and additional substituents at the meta positions of the 3-phenyl ring, which are useful as antibacterials. iv) US 5,652,238 (Brickner et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a hydroxyl acetyl piperazine moiety, active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, as well as anerobic organisms such as bacteroides and Clostridia species as well as acid-fast organisms such as Mycobacterium tuberculosis. v) US 5,684,023 (Riedl et. al.) discloses certain 3- benzofuranyl- and benzothienyl oxazolidinones, carrying an azido, hydroxy or acetyl aminomethyl group at the 5-position, useful as antibacterial medicaments. vi) US 5,688,792 (Barbachyn et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a (substituted)-morpholine. Such compounds are useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp. vii) US 5,719,154 (Tucker et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the said substitution being a pyrimidinyl or pyradazinyl group. Such compounds are useful as antimicrobial agents. viii) US 5,736,545 (Gadwood et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a five membered heterocycle ring, in particular an azolyl ring. Such compounds are useful in the treatment of microbial infections. ix) US 5,792,765 (Riedl. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-substituted phenyloxazolidinones, the substitution being a heterocyclic moiety, useful as antibacterial medicaments. x) US 5,861,413 (Habich et. al.) discloses certain 2-oxo and 2-thio-l,2-dihydroxyqoinolinyl-1-oxazolidinones, useful as antibacterial medicaments. xi) US 5,880,118 (Barbachyn et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a 4 substituted thiomorholine moiety i. e. oxazine and thiazine derivatives, useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp. xii) US 5,910,504 and US 6,124,334 (Hutchinson et. al.) collectively disclose certain substituted 5-acetyl aminomethyl-3- phenyloxazolidinones substituted at the para position of the 3-phenyl ring with a heteroaromatic moiety, which is five membered having one to four nitrogen atoms or alternatively, a benzoannulated five-membered heteroaromatic ring having one to four nitrogen atoms, useful as antibacterials. xiii) US 6,069,160 (Stolle et. al.) discloses certain substituted 5-acetyl aminomethyl-3-benzocyclopentaneoxazolidinones, containing an heteroatom, useful as antibacterial medicaments. xiv) US 6,227,868 Bl and US 6,410,728 (Sciotti et. al.) collectively disclose certain 5-acetyl aminomethyl-3-phenyloxazolidinones carrying an acetylenic moiety on the 3-phenyl ring, useful for treating bacterial infections, psoriasis, arthritis and toxicity due to chemotherapy. xv) WO 93/23384 (Hutchinson et. al.) discloses certain substituted 5-acetyl aminomethyl-3 -phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, useful for treatment of microbial infections caused by staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium. xvi) WO 97/10223 (Gadwood et. al.) discloses certain substituted 5-acetyl aminomethyl-3-aminoaryl oxazolidinone N-oxide compounds, which are exceedingly water soluble and useful in preparation of pharmaceutical compositions for combating a number of human and veterinary pathogens, staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium, Mycobacterium spp. and Mycoplasma spp. xvii) WO 98/01446 and WO 98/01447 (Betts et. al.) collectively disclose certain substituted 5-acetyl aminomethyl3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a six-membered heteroaryl ring containing two or three ring nitrogen atoms as the only ring heteroatoms, useful as antibacterial agents. xviii) WO 99/02525 (Thomasco et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted by a thiadiazolyl or oxadiazolyl moiety, useful as 5 antimicrobial agents, effective against a number of human and veterinary pathogens, including Gram-positive and Gram-negative aerobic bacteria. xix) WO 99/37630 (Gordeev et. al.) discloses oxazolidinone combinatorial libraries, compositionscontaining the same and methods of preparation thereof involving solid phase synthesis, which provides the said compounds for high-throughput screening. xx) W099/37641 (Bartel. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-bicyclene-substituted oxazolidinones, useful as antibacterial medicaments. xxi) WO 01/09107 (Gordeev et. al.) discloses certain 3-heteroaryl-5-acetyl aminomethyl oxazolidinones, substituted by a thioacyl, aminocarbonyl, alkoxycarbonyl, aminothiocarbonyl, alkoxythiocarbonyl and alkylthiocarbonyl group, useful in treating or preventing an infectious disorder in humans or animals. xxii) WO 01/42242 (Paget et. al.) discloses certain substituted 5-acetyl aminomethyl 3-substituted phenyloxazolidinones, the substitution being a bicyclic heterocyclic system, useful as antibacterial agents. xxiii) WO 02/06278 (Mehta et. al) discloses certain substituted 3-phenyl oxazolidinones and to process for synthesis of the same, the said compounds useful as antibacterial agents, effective against a large number of human and veterinary pathogens, including Gram-positive bacteria and acid fast organisms such as Mycobacterium tuberculosis. xxiv) WO 02/20515 (Madar et. al.) discloses heterocyclic phenyloxazolidinones, useful for treating bacterial infections. However, only a few of the disclosures described hereinbefore provide compounds that can be used as antimycobacterials, while most of the others are silent about the antimycobacterial activity of the disclosed compounds. A need, therefore, exists for new compounds possessing potent antimycobacterial properties for treatment of TB, which as mentioned hereinearlier is assuming alarming proportions. OBJECTS OF THE INVENTION It is thus the basic object of the present invention to synthesize, identify and provide new compounds belonging to the class of oxazolidinones, possessing potent antimycobacterial properties especially for treatment of acid fast organisms such as Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M. kansai. Another object is directed to providing antimycobacterial pharmaceutical composition effective in inhibiting/treating the generation of mycobacterial conditions/cells including Mycotacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M fortuitum and Mkansai. 6 Yet another object is directed to providing a method of treating/inhibiting mycobacterial cells/conditions involving the administrations of effective amount of the novel antimycobacterial compound and/or its salts /composition of the invention. SUMMARY OF THE INVENTION Thus according to the basic aspect of the present invention there is provided compound of formula (I) and its pharmaceutically acceptable salts thereof wherein, A, B = H, and/or F Ri is a group of formula wherein, Q is CH2-CH2, CH=CH, or C=C Y is O,S or NR3 wherein, R3 is Ci - C4 alkyl (straight, branched, unsaturated), cycloalkyl, COOH, COOR,, CHO, COCR4, CN, aryl, heteroaryl wherein, R is an alkane of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms, and Ar is an aromatic carbocycle represented by 7 wherein, X is OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, Br, CI, F, or I, M is-CHorN,and Zis-CH,-NH,OorS and wherein, R3 and R4 are as described hereinbefore, and R5 is H, or same as R4, and R.2 is selected from the groups shown below, and the corressponding N-oxides thereof Heteroaryl or Heterocycloalkyl wherein K is O, S, SO, S02, or CH2 According to another aspect of the invention there is provided a pharmaceutical composition comprising: i) atleast one of an antimycobacterially effective amounts of compound of formula I and pharmaceutically acceptable salts there of; and ii) a pharmaceutically acceptable carrier. According to yet another aspect of the present invention there is provided a method of inhibiting growth of mycobacterial cells such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M.kansai.,comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof. 8 According to yet another aspect of the present invention there is provided a method of treating mycobacterial conditions such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M kansai, comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof. According to another aspect, there is provided a process for the manufacture of the compound of formula I or its pharmaceutically acceptable salts comprising : coupling the amino fragments of compound of formula II with the carboxylic acid fragment of formula III. The above disclosed compound of formula I its pharmaceutically acceptable salts thereof are found to have antimycobacterial properties and the same in admixture with pharmaceutically active additives, an be administrated orally or paranterally for treatement of mycobacterial conditions especially TB. DETAILED DESCRIPTION OF THE INVENTION In the pharmaceutically active compound of formula (I) of this invention, the definition of the symbols and groups A, B, Rt and R2 are as follows : A is either hydrogen or fluorine, B is either hydrogen or fluorine, A and B together is hydrogen and fluorine, When A is hydrogen, B is fluorine and vice-versa. R1 represents a group of formula, Q is either an alkyl group of two carbon atoms (CH2-CH2), an alkene group of two to carbon atoms (CH=CH), or an alkyne group of two carbon atoms (C=C) 9 Y can either be oxygen, sulfur or an amino function of formula NR3, wherein R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or branched. Suitable alkyl groups are methyl, ethyl, n-propyl, n-butyl, iso-propyl, iso-butyl, tert- butyl, ethylene, propylene, 1, butene, both the geometric isomers of 2-butene i. e.(cis)-2-butene and (trans)-2-butene, and iso-butylene. or R3 is a cycloalkyl group of 3-7 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl, or R3 is a carboxylic acid group (-COOH) or a carboxylic acid ester of formula-COOR4, wherein R4 is H, an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms. R3 is further an aldehyde (-CHO), an acetyl group (-COCR4), wherein R4 is as mentioned hereinbefore or R3 is a nitrile (CN), aryl or heteroaryl, wherein Aryl is phenyl substituted with (0) or (1) of-F, -CI, -OCH3, -OH, -NH2, -CrC4 alkyl, -O-C(O)- OCH3,-N02or-CN,and Heteroaryl or Ar is a five membered ring of formula or Ar is a fused bicyclic phenyl or pyridine ring of formula 10 The group Ar is a substituted phenyl ring or a substituted pyridine ring of formula wherein, M is either CH or N; Z is -CH, -NH, O or S and R3 is as defined hereinbefore, X is a group selected from OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, F, CI, Br or I, wherein R4 is as defined hereinbefore, and R5 is hydrogen or R4. R2 is selected from the groups shown below, and the corresponding N-oxides thereof. Heteroaryl or Heterocycloalkyl wherein K is O, S, SO, S02, or CH2 The preferred novel compounds of formula (I) that form part of this invention, are as follows. The following compounds 1 to 78( named as per IUPAC or CAS nomenclature) are preferred compounds of formula (I) of the invention. 1. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide. 2. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 3. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 4. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide. 5. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 11 6. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide. 7. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide. 8. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 9. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 10. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 11. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methylphenyl) - 4- oxobutanamide. 12. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - (4 - methylphenyl) - 4- oxobutanamide. 13. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 14. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide. 15. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide. 16. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide. 17. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 18. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 19. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide. 20. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - (2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 21. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide. 22. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 23. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 12 24. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazohdinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 25. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazohdinyl methyl] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 26. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazohdinyl ] methyl - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide. 27. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 28. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl - 4 - oxo - 4 -( 2 - thienyl)butanamide. 29. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide. 30. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide. 31. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide. 32. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide. 33. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N - oxide. 34. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 35. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methoxyphenyl) - 4- oxobutanamide. 36. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - chlorophenyl) - 4- oxobutanamide. 37. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2,4 - dimethylphenyl) - 4- oxobutanamide. 38. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benztriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 39. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 40. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 41. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 13 42. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 43. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide. 44. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide. 45. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 46. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 47. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide. 48. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide. 49. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 50. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 51. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 52. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 -( 2 - thienyl)butanamide. 53. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 54. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 55. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - phenylbut - 2- enamide. 56. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo- 4 - ( 4 - thiomethylphenyl )butanamide. 57. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2 - naphthyl) - 4 - oxobutanamide. 58. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide. 59. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 14 60. (S) - N -[ [ 3 - (3 - fluoro—4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 61. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbut - 2- enamide. 62. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 63. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide. 64. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide. 65. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 66. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - (4 - thiomethylphenyl)butanamide. 67. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - ( 2 - naphthyl) - 4 - oxobutanamide. 68. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 69. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide. 70. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 71. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 72. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 73. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 74. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 75. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 76. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 77. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 15 78. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 — oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide. The respective N-oxides of the group R2 of the compounds of formula I listed above also form a novel aspect of the present invention. The pharmaceutically active compounds of formula (I), the corresponding N-oxides of the group R2 and pharmaceutically acceptable salts thereof of this invention can be prepared by methods known to one skilled in the art. Typically, compounds of formula (I), can be prepared by coupling of the amino fragment of formula (II) Scheme-! General method for synthesis of compounds of formula (I) In a typical experiment, the amine compound of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinbefore is dissolved in a 1:1 mixture of tertahydrofuran and water or a 1:1 mixture of methylene chloride and water. To the solution is added the carboxylic acid compound of formula (III), followed by addition of 1-hydroxybenztriazole (HOBt). The resulting mixture is cooled to a temperature of 0-5° C to which l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 1.1 Eq.) is added and gradually allowed to warm to room temperature and agitated at this temperature for 24 hours. At the end of 17 the reaction, a solution of saturated aqueous sodium bicarbonate is added and the organic phase separated from the aqueous phase. Evaporation of the solvent and chromatography of the residue over silica gel affords compound of formula (I), generally as white solids. The N-oxides of the group R2 of compound of formula (I) thus obtained are preferably prepared by addition of m-chloro perbenzoic acid (m-CPBA) to a cooled solution of the compound of formula (I) in a chlorinated hydrocarbon solvent such as methylene chloride and ethylene chloride and thereafter agitating the reaction mixture at room temperature for 12-15 hours. Evaporation of the solvent under reduced pressure, followed by chromatography of the residue over silica gel affords the corresponding N-oxides in high purity. The N-oxides thus prepared, while retaining most of the antimycobacterial activity of the corresponding deoxo compound exhibit exceedingly high water solubility over the deoxo analogue, thereby helping in manufacture of suitable iv formulations, which forms an important aspect of this invention. The starting materials required for synthesis of compound of formula (I), thus involve the amine compound of formula II and the carboxylic acid compound of formula III. The amine compound of formula II can be selected from i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vi) (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, and viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine. 18 The carboxylic acid compound of formula III can be selected from 4-(2-Naphthyl)-4- oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic acid, 4-oxo-4-(2'methylpropyl)phenylbutanoic acid, 4-Oxo-4- (2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 - oxobutanoic acid,4 - (2,4 - dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 - phenyl - but - 2 - ynoic acid. 20 Thus, the starting amines of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinearlier are prepared as per the method disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33, 2569-2578; C. Wang et. al., Tetrahedron, 1989, 45, 1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO 95/25106 and WO 97,21708. The method is essentially summarized in Scheme-II. In a typical method, morpholine, thiomorpholine, piperidine, 4-benzyl piperazine, pyrrolidine, 1,2,4-triazine, 12,3-benzotriazine, benzyl amine, a heterocycloalkyl or a heteroaryl moiety etc., each one of which corresponds to the group R2 defined hereinbefore is reacted with 3,4-difluoro nitrobenzene in the presence of a base and a solvent to give the corresponding derivative in which the fluorine atom at 4-position is substituted by the group R2. The nitro group in the compound thus obtained is reduced to amino group, which is thereafter protected by a suitable protective group. Reaction of the N-protected compound thus obtained with (R)-glycidyl butyrate in the presence of a strong base like n-butyl lithium leads to formation of the 5-hydroxymethyl oxazolidinone ring. The hydroxy group in the compound thus obtained is converted to sulfonyl derivative, for e.g. a methanesulfonyloxy (mesyl) or a p-toluenesulfonyloxy (tosyl) derivative by reaction with methanesulfonyl chloride or p-toluenesulfonyl chloride respectively. Reaction of the respective mesyl or tosyl derivative with sodium azide gives the corresponding azide, which is converted to the amine compound of formula (II) by standard methods, for e.g. by reaction with a triaryl/trialkyl phosphine, followed by hydrolysis. The starting carboxylic acid fragments of formula (III), wherein the group Ar has the same meaning as defined hereinearlier are prepared as per the method disclosed in Org. Reactions, 1949, 5, 229-289; Quart. Rev. Chem. Soc, 1954, 8, 355-379; Chem. Rev., 1955, 55, 229-281, and J. Am. Chem. Soc, 1947, 69, 1784-1786. The method is essentially summarized in Scheme-HI. Scheme-Ill General method for synthesis ofalkane and alkene carboxylic acid s of formula (HI) In a typical method, the aromatic compound Ar-H, wherein Ar is as defined hereinbefore is reacted with succinic anhydride in the presence of a Lewis acid, such as anhydrous aluminium chloride and in the presence of an anhydrous solvent and the mixture heated to 100° C to give the carboxylic acid derivatives of formula (HI), wherein Q is alkyl of 1-4 carbon atoms. 23 Similarly, compounds of formula (III), wherein Q is an alkene (CH=CH) are prepared by reaction of the aromatic compound Ar-H, wherein Ar is as defined hereinbefore with maleic anhydride under the same conditions mentioned hereinbefore. Compounds of formula (III), wherein Q is an alkyne (C=C) are prepared by reaction of propiolic acid ester with an aldehyde of formula Ar-CHO in the presence of butyl lithium and in the presence of an aprotic solvent such as THF at -78° C to give the corresponding secondary alcohol, which is oxidized to the keto derivative using manganese dioxide as the oxidizing agent. Saponification gives the carboxylic acid derivative of formula (ID) [ US 4,929,741 (A. Fischili et. al.) ] The synthesis is summarized in Scheme-IV. P = any protective group The synthesis of compound of formula (I) of this invention and the synthesis of the respective starting material amines of formula (II) and the carboxylic acids of formula (III) are further described herein in detail. SYNTHESIS OF THE STARTING AMINES OF FORMULA OD The amines were prepared as per the chemistry summarized in the Scheme-H and as per the methods disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33,2569-2578; C. Wang et. al., Tetrahedron, 1989, 45,1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO 24 95/25106 and WO 97,21708. Commercially available raw materials and known techniques were utilized for the synthesis. The optically pure amines as such were obtained by using optically active intermediates or resolution of racemic mixtures by a suitable reagent. The preferred enantiomer is (S), at the chiral centre on the oxazolidinone ring. Example 1 General Method for Preparation of the Amines (II) The oxazolidinone azides of general formula (8), given in Scheme-II (1.0 eq) were dissolved in dry THF (10 times by volume ) and treated with triphenyl phosphine (1.5 eq.) at room temp. The resulting solution was stirred for 6hrs at room temp. Water [2 eq. of (8)] was added and the solution heated for 6hrs at 55 - 60° C. The solvent was evaporated and the residue chromatographed on a column of silica gel (100 -200 mesh) and eluted initially with ethyl acetate and then with chloroform : methanol (4:1) to give the the amines (II) as white solids. The following amines i) to viii) of formula I were prepared by this general method, viz. i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vi) (S) - N -[3 - (3 - fluoro — 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, and viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine. SYNTHESIS OF THE STARTING CARBOXYLIC ACIDS OF FORMULA (HP Example 2 4-(2-Naphthyl)-4-oxobutanoic acid Naphthalene (5.0gm, 0.039moles) and succinic anhydride (4.68gm, 0.0468 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (11.44g, 0.0858 moles) was added at 25 room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 25 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid. Subsequent column chromatography gave a buff coloured solid. Subsequent chromatography gave 3.7 gm (41%) the title compound, mp 173-174° C. 'H NMR (CDCI3, 5) : 8.40 (s,lH), 7.7 - 8.0 ( m, 4H), 7.4 - 7.6 (m,2H), 3.33 (t,2H), 2.77 (t,2H + 1H). The filterate was concentrated to give 5.8 gm of a mixture of 4-(2-naphthyl)-4-oxobutanoic and 4-(l-naphthyl)-4-oxobutanoic acid. Example 3 4- Oxo-4-(2- ThienylJbutanoicacid Thiophene (5.0gm, 0.059moles) and succinic anhydride (7.13gm, 0.0713 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (17.43gm, 0.131 moles) was added at room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 30 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (50 ml). The solid was dried at room temp to give 9.8 gm (89%0 of the title compound, mp 103 - 107° C. !H NMR (CDCI3, 8) : 7.69 (dd, 1H), 7.58 (dd, 1H), 7.07 (dd,lH), 3.9 (bs, 1H), 3.23 (t, 2H), 2.74 (t,2H). Example 4 4- Oxo-4-(4-thiomethyl)phenylbutanoic acid Thiophenol methyl ether (8.0gm, 0.0645moles) and succinic anhydride (7.75gm, 0.0774 moles) were taken up in dichloroethane (80 ml). Aluminium chloride (18.90gm, 0.1419 moles) was added at room temperature. The resulting mixture stirred for 0.5hr and then heated at 85° C for lhr. The reaction mixture was cooled to room temperature, diluted with 40 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (80 ml). The solid was dried at room temp to give 6.9 gm (48%) of the title compound, mp 151 -154° C. H NMR (CDCI3, 5) : 7.82 (d,2H), 7.20 (d, 2H), 4.2 (bs, 1H), 3.21 (t, 2H), 2.73(t, 2H),2.45 (s,3H). 26 Example 5 4 - oxo -4- (2'methylpropyl)phenylbutanoic acid 2'methylpropylbenzene (5.0m, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles), were taken up in dichloroethane (50 ml). Aluminium chloride (10.90g, 0.0821 moles ) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 ml of a 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.7 gm (99%) of the title compound as a solid, mp 102 - 105° C. !H - NMR (CDC13, 8) : 7.83 (d,2H), 7.17(d,2H), 3.24(t,2H), 2.74(t, 2H), 2.46 (d, 2H), 1.80 (pent., 1H). Example 6 4 - Oxo - 4 - (2',2'dimethylethyl)phenylbutanoic acid 2',2'dimethylethylbenzene (5.0gm, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (10.90gm, 0.0821 moles) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 m of a 1:1 mixture of water Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.5 gm (97%) of the title compound as a solid, mp 103 — 107° C. !H-NMR (CDCI3,8) : 7.94(d,2H), 7.50 (d, 2H), 3.29 (t,2H), 2.82 (t,2H), 1.36 (s,9H). Example 7 Using the appropriate aromatic compound (Ar-H) and succinic anhydride and following exactly the method described in Examples 2-6 the following carboxylic acids can be prepared, viz. i) 4 -(4 -methylphenyl)- 4 - oxobutanoic acid, ii) 4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid, iii) 4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid, iv) 4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, v) 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, vi) 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid, vii) 4 -{2- Naphthyl)- 4 - oxobutanoic acid, viii) 4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, ix) (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and x) 4 - oxo - 4 - phenyl - but - 2 - ynoic acid. 27 SYNTHESIS OF THE COMPOUNDS OF FORMULA (D Example 7 Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - J - oxazolidinyl ] methyl] — 4-(4- naphthyl) -4- oxobutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 dichloromethane-water mixture (10 ml). To this was added 4 -( 2 - naphthyl- 4 - oxobutanoic acid (0.154gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) the resulting mixture was cooled to 0° C. l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added the resulting mixture was allowed to warm to room temperature and then stirred for 24hr. Saturated aqueous sodium bicarbonate solution (2ml) was added to the reaction mixture, stirred for 15 min and then the organic layer separated and the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.22 gm, 64%) as a white solid. MS (M+l) = 506 m/z H NMR (CDC13, 5) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, 1H ), 7.01(dd,lH ), 6.74 (t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, 1H), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91 (m,4H), 2.60(t, 2H). Example 8 Preparation of (S) -N-[[3- (3-fluoro-4-morpholinylphenyl) -2-oxo-5- oxazolidinyl ] methyl] -4- oxo -4-(2- thienyl)butanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml) . To this was added 4 - oxo - 4 (2 - thienyl)butanoic acid (0.125gm, 0. 00068 moles) and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the resulting mixture was allowed to warm to room temp and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated sodium bicarbonate was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separatedand the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.175 gm, 56%) as a white solid MS (M+1) = 462 m/z 28 lH NMR (CDC13, 8) : 7.63(d,lH ), 7.55 (dd,lH ), 7.35(dd,lH), 7.04(t, like dd, 2H), 6.83(t,lH), 6.30 (t,lH), 4.69(m,lH), 3.93 (t, 1H), 3.6- 3.8 (m, 3H),3.80 (m,4H), 3.61(dd, 2H), 3.21(dd,2H),2.97 (m,4H),2.55(t, 2H). Example 9 Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( V- methyl - 4 - propylphenyl) - 4 - oxobutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 -oxo - 5 -oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml). To this was added 4 - [ 4(2'-methylpropylphenyl)]- 4 - oxobutanoic acid (0.158gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated, and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.210gm, 60%) as a white solid. MS(M=l) = 512m/z 'H NMR (CDC13, 8) : 7.73(d,2H ), 7.52 (dd,lH ), 7.28(m,lH ),7.15(d,2H ), 7.05 (d,lH), 6.39 (t,lH), 4.75(m,lH), 3.91 (m, 4H), 3.5- 3.9 (m, 4H), 3.28 (dd, 2H), 3.16 (m,4H),2.54 (t, 2H), 2.45 (d, 2H), 1.82 (pent., 1H), 2.60 (t, 2H). Example 10 Preparation of(S) -N-[ [3 - (3 -fluoro -4- morpholinylphenyl) - 2 -oxo - J - oxazolidinyl J methyl J -4- oxo - 4 -(4- thiomethyl) phenylbutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF -water mixture (20 ml). To this was added 4 - (4-methlythiophenyl) - 4 - oxobutanoic acid (0.152g, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) and the resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142g, 0.00074 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate was added to, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The 29 combined fractions were concentrated to give the title compound (0.270 gm, 79%) as a white solid. MS (M+l) = 502 m/z JH NMR (CDC13, 5) : 7.70(d,2H ), 7.37 (dd,lH ), 7.14(d,2H ), 7.00 (dd,lH), 6.79(t,lH), 6.38 (t,lH), 4.71(m,lH), 3.86(t,lH),3.5- 3.9 (m, 4H), 3.81 (m, 4H), 3.22 (dd, 2H), 2.96 (m,4H),2.53 (t, 2H), 2.45(s,3H). Example 11 Preparation of:. (S) - N-[[3 - (3 -fluoro -4- morphottnylphenyl) — 2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) - 4 - oxobutanamide. (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.100gm, 0.00034 moles) was taken up in 1:1 THF-water mixture (20 ml) . To this was added 4 - (4- chlorophenyl) - 4 - oxobutanoic acid(0.072g, 0.00034 moles and HOBt (0.046g, 0.00034 moles) .The resulting mixture was cooled to 0°C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.071gm, 0.00037 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated and 2 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with dichloromethane. The organic layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give (0.070gm, 42%) of the title compound as a white solid. MS (M+l) = 490 m/z JH NMR (CDCI3, 8) : 7.72(d,2H ),7.37 (dd,lH ),7.31(d,2H ), 6.98 (dd,lH),6.79 (t,lH), 6.28 (t,lH), 4.69(m,lH), 3.83 (t, 1H), 3.81 (m, 4H), 3.4- 3.m (m, 3H), 3.21 (dd, 2H), 2.97 (m,4H),2.54 (t,2H). Example 12 Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 -naphthyl) - 4 - oxobutanamide - N - oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (2 -naphthyl) - 4 - oxobutanamide (0.950gm, 0.0019 moles) in dichloromethane (150 ml) was added 60% m -CPBA (0.550g, 0.0032 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The column was eluted with ethyl acetate (200 ml), followed by a mixture of chloroform : methanol 30 (4:1,600 ml).Concentration the combined fractions gave the title N-oxide (0.891g, 82% ) as a white solid. !H NMR (CDCI3, 8) : 8.59(t,lH ), 8.36(s,lH),7.7-7.9 (m,5H), 7.2 -7.5 (m,2H),7.08 (dd,lH), 6.60(t,lH), 4.76(m,lH), 4.61(bt,2H), 3.5 - 4.3 (m, 9H), 3.42 (dd, 2H), 2.83 (bdd,2H), 2.61 (bt, 2H). Example 13 Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide. To a cooled solution (0 - 5° C) of (S) - N -[[3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - oxo - 4 - (2 - thienyl)butanamide (0.850gm, 0.0017moles) in dichloromethane (120 ml) was added 60% m -CPBA (0.550g,0.0032 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The column was eluted with ethyl acetate (200ml) followed by a mixture of chloroform : methanol (4:1,600 ml).Concentration of the combined fractions gave the tile N-oxide (0.790g, 90%) as a white solid. 1HNMR( CDCI3,5) : 8.63(t,lH), 7.77(dd,lH), 7.65 (d, 1H), 7.56 (d, 1H), 7.09 (dd, 1H),7.04 (dd,lH), 6.45(t,lH), 4.68(m,lH), 4.65(bt,2H), 4.22 (dt,2H), 3.89(t,lH), 3.5 - 3.9 (m, 5H), 3.22 (dd, 2H), 3.00 (bd,2H), 2.54 (t, 2H). Example 14 Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) -4- oxobutanamide -N- oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide, (1.150gm, 0.0023 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.725gm, 0.0040 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1,600 ml). Concentration of the combined fractions gave the title N-oxide (0.950g, 80%) as a white solid. 'HNMRtCDCk 8) : 8.61(t,lH ), 7.76(d,2H), 7.72 (dd, 1H), 7.34 (d, 2H), 7.10 (dd, 1H), 6.46(t,lH), 4.70(m,lH), 4.64(bt,2H), 4.16 (dt,2H), 3.94(t,lH), 3.5 - 3.9 (m, 5H), 3.24 (dd, 2H), 2.97 (bd,2H), 2.55 (t, 2H). 31 Example 15 Preparation of(S) -N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo -5-oxazolidinyl ] methyl] -4-/4-(2'- methyl - 4 -propylphenyl) -4 — oxobutanamide -N- oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - [4 - (2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide (1.05gm, 0.0020 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.600gm) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1 , 600 ml). Concentration of the combined fractions gave the title N-oxide (0.891gm, 82%) as a white solid. JH NMR (CDC13, 5) : 8.62(t,lH ), 7.77(dd,lH), 7.75 (d, 2H), 7.14 (d, 2H), 7.12 (dd, 1H), 6.44(t,lH), 4.75(m,lH), 4.64(bt,2H), 4.20 (dt,2H), 3.95(t,lH), 3.91 (t,lH) 3.5-3.9 (m, 4H), 3.26 (dd, 2H), 2.99(bd,2H), 2.57 (t, 2H),2.44(d,2H), 0.83(d,6H). Example 16 Preparation of (S)-N-ff3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4- methylphenyl)-4-thiooxobutanamide To a solution of (S)-n- of (S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4-methylphenyl)-4-oxo-butanamide (0.1 Ogm, 0.00021 moles) in dry THF (5ml) was added Lawessons Reagent (0.052gm, 0.000128 moles) and the resulting solution heated under reflux for 8 hr. The reaction mixture was cooled to room temperature and to this was added saturated aqueous sodium carbonate solution (3ml) and then extracted with ethyl acetate. The solvent was evaporated off and the residue chromatographed over silica gel and eluted with a mixture of ethyl acetate-hexane to give the title compound (0.023 gm, 23%) as a white solid, mp 149-151° C. lH NMR (CDCI3,5) : 8.60 (m, 1H), 7.68 (d, 2H), 7.34 (dd, 1H), 7.14 (d, 2H), 6.96 (dd, 1H), 6.81 (t, 1H), 4.90 (m, 1H), 4.20-4.40 (m, 1H), 3.80-4.0 (m, 4H), 3.50 (m, 2H), 2.90-3.00 (m, 6H). Example 17 Using the appropriate amine compound (II) and the carboxylic acid (HI) and following exactly the method described in Examples 7-16 the following carboxylic acids can be prepared, viz. (S) - N-[ [ 3 - (3-fluoro — 4- morpholinylphenyl) -2- oxo — 5- oxazolidinyl J methyl] — 4-(4- methylphenyl) -4- oxobutanamide. 32 'H NMR (CDCI3, 5) : 7.78 (d, 2H ), 7.44 ( d, IH ), 7.22 ( d,2H ), 7.09 ( d, IH ), 6.88 ( t, IH ), 6.41(t, IH), 4.76 (m, IH ), 3.6 - 4.1 (m, 4H ), 3.86 ( m, 4H ), 3.31 ( dd, 2H ), 2.61 (t, 2H ), 2.40 (s.3H). (S) -N-[[ 3-(3 -fluoro -4 - benzylpiperazinyl) phenyl] -2- oxo - 5 - oxazolidinyl] methy ] -4-oxo -4-phenylbutanamide. lH -NMR (CDC13, 5) : 7-88 ( d,2H ), 7.61 (dd, IH), 7.38 ( m, 5H ), 7.2 - 7.4 (m, 5H), 6.88 (t, IH ), 6.55 (t, IH ), 4.77 ( m, IH), 3.94 (t, IH), 3.5 - 3.7 (m, 3H ), 3.71 ( s, 2H ), 3.34 (dd, 2H ), 3.12 (m, 4H),3.12 (m, 4H ), 2.61 (t, 2H ). (S) - N-f]3 - ( 3 -fluoro - 4 - [methylbenzylamin]phenyl) - 2 - oxo -5 - oxazolidiny] methy ]-4-(4- methyl phenyl) -4- oxobutanamide. H NMR (CDCI3, 8) : 7.90 ( d, 2H ), 7.52 ( dd, IH ), 7.2 - 7.5 ( m, 8H ), 7.05 ( d, IH ), 6.84 (t, IH ), 6.50 (t, IH ), 4.75 (m, IH ), 4.48 (s, 2H ), 3.95 (t, IH), 3.6 - 4.1( m,3H ), 3.64 ( dd, 2H ), 2.71 (s,3H), 2.62 (t,2H). (S)-N-[[3-(3-fluoro-4- benzotriazolylpheny)-2-oxo-5-oxazolidinyl]methy]-4-oxo - 4 -phenylbutanamide. !H NMR ( CDCI3, 5) : 8.16 ( d,lH), 7.84 (d, 2H), 7.66 (t, IH), 7.2 -7.6 (m, 8H), 6.46 (t, IH ), 4.90 (m, IH), 3.98 (t,lH), 3.9 - 4.0 (m, 2H ), 3.65 (m, IH ), 3.39 (ddd, 2H ), 2.65 ( ddd, 2H). (S) -N-[[3-(3-fluoro-4- pyrrolidinylphen) -2-oxo-5- oxazolidinyl]methyl]-4-oxo - 4 -phenylbutanamide. !H NMR (CDCI3, 8) : 7.90 (d,2H ), 7.52 (dd, IH ), 7.44 (d, 2H ), (dd, IH ), 7.04 (dd, IH), 6.65 (t, IH), 6.43 (t, IH), 4.74 (m,lh), 3.93 (t,lH), 3.77 (t,lH), 3.6 3,8 (m, 2H), 3.33 (m, 6H ), 2.63 (t, 3H), 1.94 (m,4H). (S)-N-[[3-(3-fluoro-4- benzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methy]-4-(4- methlyphenyl) - 4- oxobutanamide. !HNMR (CDCU, 8) : 8.16 (d, IH ), 7.3 - 7.9( m,7H), 7.78 (d,2H ), 7.21(d,lH), 6.54(t, IH), 4.89 ( m, IH), 3.8 -42 (m, 3H ), 3.4 - 3.7 (m, 3H ), 2.63 (dd, 2H ), 2.23 (s, 3H ). (S)-N-][3-(3 -fluoro - 4 - thiomorpholinylphenyl) -2 — oxo - 5 - oxazolidinyl] methyl] -4- oxo- 4 -phenylbutanamide. !H NMR (CDCI3, 8) : 7.89 (d, 2H ), 7.39 - 7.60 ( m, 4H ), 7.11 (dd, IH ), 6.90 (t, IH), 6.39 ( t,lH ), 4.76 (m,lH ), 3.94 (t,lH ), 3.80 (t, IH ), 3.6 - 3.7 ( m, 2H ), 3.36 ( dd, 2H ), 3.28 ( m,4H), 2.80 ( m,4H ), 2.62 (t, 2H). (S) — N-[[3 - (3 -fluoro - 4 - benzylpiperazinyl) phenyl] — 2 — oxo — 5 - oxazolidinyl] methyl]- 4-(4- methylphenyl) -4- oxobutanamide. 33 H NMR (CDCI3, 5) : 7.81 ( d, 2H), 7.2 - 7.5 ( m, 8H ), 7.08 (dd, IH ), 6,89 (t, IH ), 6.39 (t, IH ), 4,78 ( m, IH ), 3.95( t, IH), 3.79 (t, IH), 3.6 - 3.7 (ni, 2H ), 3.61(s, 2H), 3.31 ( m,2H), 3.09 (m,4H), 2.65 (m,6H), 2.41 (s, 3H). (S)-N-[[3-(3-fluoro-4- piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl]-4- oxo - 4 - phenylbutanamide. !H NMR (CDCI3, 8) : 7.90(d,2H ),7.60 (dd,lH ),7.45(d,2H ), 7.39 (dd,lH), 7.10 (dd,lH), 6.90 (t,lH), 6.55 (t,lH), 4.78(m,lH), 3.95 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.35 (m, 2H), 3.00 (m,4H0,2.63 (t, 2H), 1.9-1.6 (m,6H). (S)-N-[[3- (3 -fluoro-4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4-(4 - methylphenyl) - 4- oxobutanamide. JH NMR (CDCI3, 5) : 7.79(d,2H ),7.40 (dd,lH ),7.23(d,2H ), 7.09 (dd,lH), 6.91 (t,lH), 6.40 (t,lH), 4.77(m,lH), 3.98 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.30(t, 2H), 2.98 (m,4H), 2.62 (t, 2H),2.41(s,3H), 1.6-1.9 (m,6H). (S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5- oxazolidinyl] methyl]- 4 -(4- methylphenyl) - 4- oxobutanamide. 'H NMR (CDCI3, 8) : 7.80(d,2H ),7.32 (dd,lH ),7.21(d,2H ), 7.01 (dd,lH), 6.60 (t,lH), 6.40 (t,lH), 4.75(m,lH),4.12(m,lH) 3.94 (t, IH), 3.75 (t, IH), 3.4- 3.6 (m, 2H), 3.34 (m, 6H), 2.61 (t, 2H),2.40(s,3H), 1.9(m,4H). (S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4 -(4- methoxyphenyl) -4- oxobutanamide. lU NMR (CDCI3, 8) : 7.79(d,2H ),7.36 (dd,lH ), 7.00 (dd,lH), 6.82 (d,2H), 6.80(t,lH), 6.38 (t,lH), 4.69(m,lH), 3.80 (s, 3H), 3.78 (m, 4H), 3.4- 4.0 (m, 4H), 3.20 (dt, 2H), 2.97 (m,4H),2.55 (dt,2H). (S) -N-[[3-(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4- (2 -naphthyl) -4- oxobutanamide. !H NMR (CDCI3, 8) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, IH ), 7.01(dd,lH ), 6.74 (t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, IH), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91 (m,4H), 2.60(t, 2H). ((S) - N -[[ 3 - (3 -fluoro -4- morpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4- (2, 4-difluorophenyl) -4-oxobutanamide. !H NMR (CDCI3, 8) : 7.73(ddd,2H ), 7.47 (dd,lH ), 7.01(dd,lH ),6.7 - 6.9(m,3H ), 6.30 (t,lH), 4.75(m,lH), 3.89 (m, 4H), 3.5- 3.9 (m, 4H), 3.20 (m, 2H), 3.09(m,4H), 2.52 (t, 2H). (S)-N -[[ 3-(3 -fluoro -4- morpholinylphenyl) -2- oxo -5— oxazolidinyl] methyl] - 4 -[4- (2s',2'- dimethyl- 4 - ethylphenyl) -4- oxobutanamide. 34 !H NMR (CDC13, 8) : 7.75(d,2H ), 7.37 (d,2H ), 7.35(dd,lH ), 7.05 (dd,lH), 6.82(t,lH), 6.37 (t,lH), 4.71(m,lH), 3.5- 3.9 (m, 4H), 3.80 (m, 4H), 3.25 (dt, 2H), 2.97 (m,4H),2.54 (t, 2H), 1.26(s,9H). (S) -N-ff 3 - (3 -fluoro - 4 -fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] -4-(4- methoxyphenyl) -4- oxobutanamide. lU NMR (CDC13, 8) : 7.76(d,2H ), 7.37 (dd,lH ), 7.16(m,5H ), 6.93 (dd,lH), 6.79(d,2H),6.74 ( t,lH), 6.37 (t,lH), 4.66(m,lH),4.14 (s,2H), 3.84(t,lH), 3.74 (s,3H), 3.4- 3.8 (m, 3H), 3.18 (dd, 2H), 2.62(s,3H),2.5 l(t, 2H). (S) -N-ff 3 - (3 -fluoro - 4 - fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl] methy] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide. 'H NMR (CDCU, 8) : 7.77(d,2H ), 7.37 (dd +d,3H ), 7.19 -7.22(m, 3H), 6.98 (dd,lH), 6.77(t,lH), 6.31 (t,lH), 4.69(m,lH), 4.17(s,2H), 3.89(t,lH)„3.72 (dd,lH), 3.5- 3.6 (m, 2H), 3.25 (dd, 2H), 2.64 (s,3H),2.55 (t, 2H), 1.25(s,9H). (S) -N-ff 3 -(3 -fluoro - 4 -[methylbenzylamino]phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] -4- (2,4 - dimethylphenyl) -4- oxobutanamide. lU NMR (CDCI3, 8) : 7.65(d,lH ), 7.46 (dd,lH ), 7.32(m,5H ), 7.04(m,3H), 6.95(t,lH), 6.36 (t,lH), 4.78(m,lH), 4.27(s,2H), 3.97(t,lH),3.6- 3.8 (m, 2H), 3.81 (t, IH), 3.27 (dd, 2H), 2.77 (s,3H),2.61 (t, 2H), 2.44(s,3H), 2.35 (s, 3H). (S)-N -[[ 3-(3 -fluoro -4- tnorpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] - 4 - (2,4 - dimethylphenyl) -4- oxobutanamide. 'H NMR (CDCU, 8) : 7.652(d,lH ), 7.42 (dd,lH ), 7.0- 7.1(m,3H), 6.86(t,lH), 6.38 (t,lH), 4.79(m,lH), 3.95(t,lH),3.5- 3.9 (m, 2H), 3.87 (m, 4H), 3.25(dd, 2H), 3.02 (m,4H), 2.59 (t, 2H), 2.41(s,3H), 2.34 (s, 3H). ^ -N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) —2 — oxo -5 — oxazolidinyl] methyl] — 4 — (2,4 - dimethylphenyl) - 4 - oxobutanamide. JH NMR (CDCI3, 8) : 7.62(d,lH ), 7.31 (dd,lH ), 7.03(s,+dd, 3H ), 6.60(t,lH), 6.36 (t,lH), 4.74(m,lH), 3.94(t,lH), 3.76 (dd, lH),3.67(m, 2H), 3.30 (m, 4H), 3.24 (dt, 2H), 2.60 (t, 2H), 2.44(s,3H), 2.34 (s, 3H).1.94 (m,2H). (S) -N-ff 3-(3-fluoro-4- benztriazolylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4- (2,4- dimethylphenyl) -4-oxobutanamide. !H NMR (CDCI3, 8) : 8.15(d,lH ), 7.80 (dd,lH ), 7.3 -7.7(m,6H ), 7.02(d,2H), 6.39 (t,lH), 4.87(m,lH), 4.07(t,lH), 3.96(t,lH), 3.89 (dq, IH), 3.75(dt,lH), 3.38 (qt, 2H), 2.62 (m, 2H), 2.39(s,3H), 2.26 (s, 3H). (S) - N-ff 3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4- oxo -4-(2- thienyl)butanamide. 35 H NMR (CDC13, 8) : 7.71(d,lH ), 7.63 (d,lH ), 7.31(dd,lH ), 7.11 (t, lH),7.05(dd,lH), 6.68(m,lH), 6.38 (t,lH), 4.74(m,lH), 3.95(t,lH), 3.77 (t, 1H),3.6- 3.7 (m, 2H), 3.36 (m, 4H), 3.28 (t, 2H), 2.63 (t, 2H), 1.96 (m,2H). (S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo - J - oxazolidinyl] methyl] - 4 - oxo -4-(2- thienyl)butanamide. !H NMR (CDC13, 8) : 8.08(d,lH), 7.77(dd,lH ), 7.3 - 7.7(m,7H ), 7.02(t,lH), 6.45 (t,lH), 4.81(m,lH), 4.00(t,lH),3.7- 4.0 (m, 2H), 3.57 (dt, 1H), 3.25 (m, 2H), 2.55 (m,2H). (3? -N-[[3-(3-fluoro-4- morpholinylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4- oxo - 4 -phenylbut - 2- enamide. JH NMR (CDCI3, 8) :7.92 (d,lH), 7.84 (,d,lH), 7.2 - 7.6 (m, 6H), 6.98 - 7.1 (m, 3H), 4.38(m, 1H), 3.5 - 4.1 (m, 4H), 3.84 (m, 4H), 3.03 (m, 4H). (S) -N-[[3-(3 -fluoro-4- piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4-(4 - methoxyphenyl) - 4- oxobutanamide. 'HNMR^MSOde, 8) : 8.25 (t, 1H), 7.79 (d, 2H), 7.38 (dd, 1H), 7.71 (dd, 1H), 6.95 (t,lH), 6.93 (d, 2H + 1H), 4.65 (m,lH), 3.75 (s,3H), 3.99 (t, 1H), 3.64 (dd, 1H), 3.06 (t, 2H), 2.81(m,4H), 1.3 -1.6(m.6H). (S) -N-[[3-(3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4 - chlorophenyl) - 4- oxobutanamide. lH NMR (CDCI3, 8) : 7.73(d,2H ), 7.33 (d,2H ), 7.2 - 7.8 (m, 2H),6.96(dd,lH), 6.34 (t,lH), 4.72(m,lH), 3.84(t,lH), 3.5- 3.8 (m, 3H), 3.21 (dd, 2H), 2.98 (m, 4H),2.54(t,2H), 1.5 - 1.7 (m,6H). (S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl] -4-(2,4 - dimethylphenyl) - 4- oxobutanamide. 'H NMR (CDCI3, 8) : 7.55(d,2H ), 7.4 (m,lH ), 6.9 - 7.0 (m, 3H),6.32(t,lH), 4.70(m,lH), 3.90(t,lH), 3.74 (t,lH), 3.5- 3.7 (m, 2H), 3.20 (dd, 2H), 2.9 - 3.1 (m, 4H),2.52(t,2H), 2.34 ( s,3H), 2.71 (s, 3H ), 1.5 -1.9 (m,6H). (S) - N-[[3 - (3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- methoxyphenyl) -4-oxobutanamide. XH NMR ( CDCI3, 8) : 8.07(d, 1H), 7.2 - 7.8 (m,6H), 7.71(d,2H ), 6.79 (d,2H ), 6.51(t,lH), 4.81(m,lH), 3.4- 4.0 (m, 4H), 3.71 (s, 3H), 3.15 (qt, 2H), 2.52 (dd, 2H). (S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- chlorophenyl) -4-oxobutanamide. 'H NMR (CDCI3, 8) : 8.09(d, 1H), 7.2 - 7.8 (m,6H), 7.75(d,2H ), 7.35 (d,2H ), 6.29(t,lH), 4.81(m,lH), 3.7 - 4.0(m, 3H), 3.5 - 3.7 (bt, 1H),3.25 (qt, 2H), 2.55 (t, 2H). (S)-N-[[3-(3-fluoro-4-(1,2,4-triazolyl)phenyl)-2-oxo-5- oxazolidinyljmethyl] -4- oxo — 4 - phenylbutanamide. 36 H NMR (CDCI3, 8) : 8.62 (bs, 1H ), 8.10 ( s, 1H ), 7.7 -7.8 ( m, 2H ),, 7.67 (dd, 2H, ), 7.44 (t, 1H ), 7.2 - 7.4 (m,3H ), 6.49 (t, 1H ), 4.78 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55 (dt, 1H ), 3.30 (ddd, 2H), 2.54 (dd, 2H). (S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4- methylphenyl) -4- oxobutanamide. XHNMR (CDC13, 8) : 8.71 (bs, 1H ), 8.10 ( s, 1H), 7.7 -7.9 ( m, 4H ), 7.30 (d, 1H, ), 7.21 (d, 2H ), 6.63 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.64(dt, 1H ), 3.35 (qdd, 2H), 2.5 - 2.6 (m, 2H), 2.35( s,3H). (S) - N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] - 4-(4- methoxyphenyl) -4- oxobutanamide. 'H NMR (CDCI3, 8) : 8.68 (bs, 1H ), 8.16 ( s, 1H ), 7.7 -7.9 ( m, 2H ), 7.79( d, 2H ) 7.28 (dd, 1H), 6.85 ( d,2H), 6.58 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.82(s,3H), 3.61(dt, 1H ), 3.32 (qdd, 2H), 2.65 (ddd, 2H). (S) -N-][3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl] -4-(2,4- dimethylphenyl) -4- oxobutanamide. !HNMR (CDCI3,8) : 8.69 (bs, 1H ), 8.17 ( s, 1H ), 7.78( t,lH), 7.75 ( d,lH ), 7.60 (d,lH),7.25(d, 1H, ), 7.10 (d, 1H ),6.99(s, 1H ), 6.54( t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.65(dt, 1H ), 3.25 (qt, 2H), 2.59 (dt, 2H), 2.38( s,3H), 2.29 (s,3H). (S) -N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4- oxo- 4 -(4 - thiomethylphenyl)butanamide. 'H NMR (CDCI3, 8) : 8.57 (bs, 1H ), 8.06 ( s, 1H ), 7.77 (m,2H), 7.61 (d, 2H), 7.19 ( d, 1H ), 7.10 (d, 2H, ), 6.47 (t, 1H ), 4.76 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25 (qdd, 2H), 2.55 (dq,2H),2.39(s,3H). (S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide. lU NMR (CDCI3, 8) : 8.58 (bs, 1H ), 8.06 ( s, 1H ), 7.80(t,lH),7.6 -7.8 ( m, 1H ), 7.67 (d, 2H,),7.32(d,2H), 7.26 (d, 1H ), 6.43 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25 (qt, 2H), 2.53(dt, 2H), 1.22( s,9H). (S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(2'- methyl - 4 - propylphenyl) -4- oxobutanamide. 'H NMR (CDCI3, 8) : 8.61 (bs, 1H ), 8.09 ( s, 1H ), 7.6 -7.8 ( m, 4H ), 7.24 (dd, 1H, ), 7.07 (d, 2H ), 6.38 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.54(dt, 1H ), 3.28(qt, 2H), 2.54(dt, 2H), 2.40( d,2H), 1.77 (pent.,lH), 0.81 (d,6H). (S) - N-[[ 3-(3 -fluoro -4- (1,2,4 — triazolyl) phenyl) -2- oxo -5— oxazolidinyl] methyl] -4-oxo - 4- (2- thienyl)butanamide. 37 'HNMR (CDCI3, 8) : 8.57 (bs, IH ), 8.05 ( s, IH ), 7.76 (t,lH),7.60(dd,lH), 7.53 (dd,lH), 7.25 (dd, IH, ), 7.01 (d, 2H ), 6.47( t, IH ), 4.78 ( m, IH), 3.7 - 4.0 (m, 3H), 3.56(ddd, IH ), 3.25 (qt, 2H), 2.54 (dt, 2H). (S) -N-[[3 -(3 -fluoro -4- (1,2,4-triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl]- 4 - (2-naphthyl) -4- oxobutanamide. !H NMR (CDCI3, 8) : 8.41 (s, IH ), 8.27( s, IH ), 8.02(s,lH), 7.3 -7.9 ( m,6H ), 7.3 - 7.6 (m, 3H), 6.44 (t, IH ), 4.77 ( m, IH), 3.7 - 4.0 (m, 3H), 3.2- 3.7 (m, 3H), 2.5-2.6 (m, 2H). (S) - N-[[3 - (3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4- chlorophenyl) -4- oxobutanamide. lH NMR (CDCI3, 8) : 8.58 (bs, IH ), 8.07 ( s, IH ), 7.6 -7.9 ( m, 2H ), 7.68 (d, 2H), 7.29 (d, 2H,), 7.2 - 7.3 (m, IH ), 6.31 (t, IH ), 4.81 ( m, IH), 3.7 - 4.1 (m, 3H), 3.55(dt, IH ), 3.25 (qt, 2H), 2.55(dt, 2H). (S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4- oxo -4-(2- thienyl)butanamide. H NMR (CDCI3, 8) : 7..5 - 7.7 ( m, 2H), 7.3 - 7.5 (m,lH), 6.8 - 7.3(m,3H ), 6.35(t,lH), 4.69(m,lH), 3.89 (t,lH), 3.76(t,lH),3.59(m,2H), 3.21(dd,2H),3.02 (m, 4H), 2.55 (t, 2H), 1.5 - 1.8 (m,6H). (S) -N-[[3 -(3-fluoro -4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4- (2'- methyl -4- propylphenyl) -4- oxobutanamide. 'H NMR (GDCI3,8) : 8.08 (m, IH ), 7.74 (d, 2H), 7.4 - 7.8 (m, IH ), 7.16 (d, 2H,), 6.97(dd,lH) 6.37 (t, IH ), 4.74 ( m, IH), 3.88 (t, IH), 3.80(t,lH), 3.4 - 3.71 (m, 2H), 3.40(m,4H) 3.25(dd, 2H ), 2.45(d, 2H), 1.80 (pent, IH), 1.5-1.8(m,6H),0.83(d,6H). (S)-N-[[3-(3-fluoro-4-piperidylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(4 - acetamidophenyl) -4- oxobutanamide. 'H NMR (DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.78 (d, 2H), 7.60 ( d, 2H), 7.36 (dd, IH), 7.06 (dd, IH), 6.93 (t,lH), 4.63 (m, IH), 3.95(t,lH), 3.61 (dd,lH), 3.07(dd,lH), 2.81 (m,4H), 1.99 (s, 3H), 1.55 (m, 4H), 1.44 (m, 2H). (S) - N-ff 3 -( 3 -fluoro - 4 * piperidylphenyl) - 2 - oxo - J - oxazolidinyl] methyl] -4- oxo - 4 -phenylbut - 2- enamide. JHNMR (CDCI3, 8) .-7.7-8.0 (m,3H), 7.2 - 7.6 (m, 5H), 7.01 (d,2H), 6.98 (t, IH), 4.80(m, IH), 4.01(t,lH), 3.85(t,lH), 3.77 (t, 2H), 3.16 (m, 4H), 1.5 - 1.9 (m,6H). (S) - N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] ~4- oxo- 4-(4- thiomethylphenyl)butanamide. lU NMR (CDCI3, 8) :7.70 (d,2H), 7.60 (bd,lH), 7.0 - 7.3 (m, 3H), 6.91 (d,lH), 6.47 (t, IH), 4.71(m, IH), 3.87(t,lH), 3.4 - 3.8 (m,3H ), 3.45(m, 4H) 3.21 (dd, 2H), 2.54 (t, 2H), 2.45 (s,3H), 2.06(m,4H). 38 (S)-N-[[3-(3-fluoro-4-pyrrolidinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(2-naphthyl) -4- oxobutanamide. !H NMR (CDC13, 8) : 8.35 (s, IH ), 7.5 - 8.1 (m, 8H ), 6.91(d,lH) 6.53 (t, IH ), 4.72 ( m, IH), 3.38 (m, 4H), 3.2 - 4.0 (m, 6H), 2.61(m, 2H), 1.99 (m,4H). (S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] — 4 — (2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide. lU NMR (CDCI3, 8) :7.75 (d,2H), 7.46 (m,lH), 7.1 - 7.3 (m, 3H), 6.95 (d,lH), 6.44 (t, IH), 4.70(m, IH), 3.3 - 4.0 (m,4H ), 3.41(m, 4H) 3.24 (dd, 2H), 2.55 (t, 2H), 2.45 (d,2H), 2.01(m,4H), 1.81 (pent,lH), 0.83 (d, 6H). (S) -N-][3-(3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4- (2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide. lH NMR (CDCI3, 8) :7.76 (d,2H), 7.2 7.5(m, 4H), 6.95 (d,lH), 6.33 (t, IH), 4.69(m, IH), 3.88(t,lH), 3.71(t,lH), 3.6 - 3.7 (m,2H ), 3.45(m, 4H) 3.23 (dd, 2H), 2.56 (t, 2H), 1.94 (m,4H), 1.26(s,9H). (S^J - N-[[3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4 — (4 - acetamidophenyl) -4- oxobutanamide. 'H NMR (CDCU, 8) : 7.2 - 7.8 (m, 7H), 6.85 (d,lH), 6.47 (t, IH), 4.67(m, IH), 3.81(t,lH), 3.3 - 3.7 (m,3H ), 3.46(m, 4H) 3.16 (m, 2H), 2.3 - 2.9 (m,6H), 2.06(s,3H). (Sp -N-[]3-(3-fluoro -4- pyrrolidinylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4- oxo - 4 -phenylbut - 2- enamide. 'HNMR (CDCI3, 8) :7.8 - 7.9 (m,3H), 7.0 - 7.6 (m, 5H), 6.93 (d,lH), 6.75 (m,lH), 4.76(m, IH), 4.02(t,lH), 3.74 (m, 3H), 3.30 (m, 4H), 1.95 (m,4H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]- 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. !HNMR (CDCI3, 8) :7.78 (d,2H), 7.33 (dd,lH),6.99 (d,lH), 6.83 (t,lH), 6.81 (d, 1H),6.38 (t, IH) 4.69(m, IH), 3.86 (t,lH), 3.79 (s,3H), 3.5 - 3.8 (m,3H ), 3.41(m, 4H) 3.20 (m, 6H), 2.73(m,4H) 2.53 (t, 2H). (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5- oxazolidinyl]methyl]- 4 - (2,4 - dimethylphenyl) -4- oxobutanamide. !H NMR (CDCI3, 8) :7.55 (d,lH), 7.33 (dd,lH), 6.96 (m,3H), 6.81(t,lH), 6.22 (t, IH), 4.69(m, IH), 3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.17(m, 6H) 2.73 (t, 2H), 2.45 (d,2H),2.51 (t,2H), 2.34(s,3H), 2.27 (s,3H). (Si)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]- 4 - oxo -4-(2- thienyl)butanamide. !H NMR (CDCI3, 8) :7.63 (d,lH), 7.55 (d,lH), 7.33 (dd, IH), 7.05 (dd,2H), 6.85(t, IH), 6.31 (t,lH), 4.69(m, lH),3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.23(m, 6H) 2.73 (m, 4H), 2.55 (t, 2H). 39 (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - J - oxazolidinyl] methyl] -4-(4- acetamidophenyl) -4- oxobutanamide. 'HNMR ( DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.73(d, 2H), 7.59 (d, 2H), 7.38 ( dd, IH), 7.08(dd,lH), 6.99 (t, IH), 4.65 (m, IH), 3.95(t,lH),3.62(dd,lH), 3.08(m, 6H), 2.66 (m, 4H), 1.97 (s,3H). (S) - N -[[ 3 - (3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] - 4 -oxo - 4 - (4 - thiomethylphenyl)butanamide. •HNMR (CDC13,8) : 7.70 (d, 2H), 7.32 (dd,lH),7.14 (d, 2H,), 6.99(dd,lH), 6.82(t,lH), 6.33 (t, IH ), 4.68 ( m, IH), 3.86 (t, IH), 3.4 - 3.8 (m, 3H), 3.20(dt, 2H ), 2.90(t,4H) 2.53(t, 2H), 2.44(s,3H), 1.67 (m,4H), 1.5 (m,2H). (S) -N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl] -4-(naphthyl) -4- oxobutanamide. 'H - NMR ( CDCI3) : 8.36 (s, IH ), 7.7 - 7.9 (m, 4H, ), 7.4 - 7.6 (m, 2H ), 7.32 (dd,lH), 6.99(d,lH), 6.78(t,lH), 6.43 (t, IH), 4.70 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.39(dt,2H), 2.86(t,4H), 2.61(t, 2H), 2.10(m,4H),1.50 (m,2H). S) -N-[[ 3- (3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide. lUNMR (CDCI3,8) : 7.75 (d, 2H), 7.37 (d,2H),7.31 (dd, IH, ), 7.00(dd,lH), 6.84(t,lH), 6.37 (t, IH ), 4.68 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.25(dt, 2H ), 2.91(t,4H) 2.54(t, 2H), 2.23(m,4H), 1.5 (m,2H), 1.26(s,9H). (S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4-oxo -4-(4- thiomethylphenyl)butanamide. 'HNMR (CDCI3, 8) : 8.08 (d, 2H ), 7.77 (dd, IH, ), 7.63(d,2H), 7.2 - 7.5 (m, 4H ), 7.12 (d,2H), 6.41 (t, IH ), 4.81 ( m, IH), 3.98 (t, IH), 3.7 - 3.9 (m, 2H), 3.54(dt,lH), 3.22(qdd,2H), 2.54(dd, 2H), 2.36(s,3H). (S) -N-[] 3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5 - oxazolidiny] methyl] -4-(2-naphthyl) -4- oxobutanamide. 'HNMR (CDCI3, 8) : 8.35( s,lH), 8.08 (d, IH ), 7.6 - 7.8(tn,5H), 7.2 - 7.6 (m, 7H ), 6.41 (t, IH ), 4.82 ( m, IH), 3.8 - 4.0 (m, 3H), 3.3 - 3.7(m,3H), 2.64(dd, 2H). (S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4 - (2',2' - dimethyl- 4 - ethylphenyl) -4- oxobutanamide. *H NMR (CDCI3, 8) : 8.08 (d, IH ), 7.80 (dd, IH, ), 7.70(d,2H), 7.57(t, IH), 7.2 - 7.5 (m, 4H ), 7.08 (d,2H), 6.41 ( t, IH ), 4.80 ( m, IH), 3.7 - 4.0 (m, 3H), 3.55(dt,lH), 3.1 - 3.4(m,2H), 2.54(dd, 2H), 2.37(d,2H), 1.72(pent,lH), 0.76(d,6H). 40 (S)-N-[[3-(3-Jluoro-4- henzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide. JHNMR(CDC13, 5) :7.2 - 8.0 (m,13H), 6.95 (d,lH), 6.65 (m,lH), 4.89(m, IH), 4.18(t,lH), 3.7-4.0 (m, 3H). (S) -N-[[3-(3-Jluoro-4-benztriazolylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 -(4- acetamidophenyl) -4- oxobutanamide. !HNMR (DMSOde, 8) : 10.16 (s, IH), 8.29(t, IH), 8.12 (d, IH), 7.79 (m, 4H), 7.58 ( d, 2H), 7.4 - 7.5 (m, 4H), 4.74 (m, IH), 4.13(t,lH),3.08(dd,lH), 3.10 (t, 2H), 1.97 (s, 3H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide. lH NMR (CDCI3,8) : 7.76 (d, 2H), 7.53 (dd, 1H),7.39 (d, 2H +1H, ), 7.02(d,lH), 6.29 (t, IH ), 4.71 ( m, IH), 3.89 (t, IH), 3.79(t,lH), 3.5 - 3.7 (m, 2H), 3.38(m, 4H ), 3.24 (dd,2H), 2.92(m,4H) 2.54(t, 2H), 1.26(s,9H). (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide. JH NMR (CDCU, 8) :7.8 - 7.9 (m,3H), 7.3 - 7.7 (m, 5H), 6.8 -7.0 (m,3H), 4.81(m, IH), 4.05(m,lH), 3.75 (m, 3H), 3.49 (m, 4H), 3.10 (m,4H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(fi- naphthyl) -4- oxobutanamide. !H NMR (CDCI3, 8) : 8.35 (s, IH), 7.7-8.0 (m, 4H), 7.3-7.7 (m, 5H), 7.01 (m, IH), 6.48 (m, IH), 4.74 (m, IH), 3.80 (m, 3H), 3.60 (m, IH), 3.37 (m, 6H), 2.93 (m, 4H), 2.60 (m, 2H) (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4- (4- chlorophenyl) -4-oxobutanamide. !H NMR (CDCI3, 8) : 7.74 (d, 2H), 7.54 (d, IH), 7.34 (d, 2H+1H), 6.98 (d, IH), 6.35 (t, IH), 4.78 (m, IH), 3.88 (t, IH), 3.5-3.8 (m, 3H), 3.38 (m, 4H), 3.22 (dd, 2H), 2.93 (m, 4H), 2.54 (t, 2H). (S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4 - (2,4 - dimethyl- 4 ethylphenyl) -4- oxobutanamide. lH NMR (CDCI3, 8) : 7.95 (m, IH), 7.74 (d, 2H+1H), 7.77 (d, 2H), 7.07 (d, IH), 6.38 (t, IH), 4.76 (m, IH), 3.91 (t,lH), 3.4-3.8 (m, 3H), 3.58 (m,4H), 3.25 (dd, 2H), 3.1 (m, 4H), 2.54 (t, 2H), 2.46 (d, 2H), 1.80 (pent, IH), 0.85 (s, 3H), 0.82 (s, 3H). Microbiology: Pharmacological testing The compound of formula (I) of the present invention displayed antimycobacterial activity when tested by in vitro growth inhibition assay and agar incorporation methods. The minimum inhibitory concentrations (jag/ml) obtained for representative compounds of formula (I) 41 against M. tuberculosis including sensitive and resistant strains are summarized in Table-I. The MIC value of a representative preferred Compound No. 30 of formula I against different species of mycobacteria is summarized in Table-II. in vitro Growth Inhibition assay The ability of the compounds 1-78 of formula (I) of this invention to inhibit the growth of Mycobacterium species was determined by the BACTEC 460 TB system. The reference strain M tuberculosis H37Rv ATCC 27294 was grown in Middlebrook 7H9 broth containing 10% ADC supplement at 37°C on a rotay shaker at 150 rpm for grown for 7days. The turbidity of the culture was adjusted to 1.0 Mc farland. The BACTEC 7H12B medium vials were seeded with 0.1ml of the 1.0 Mc farland adjusted M. tuberculosis culture. In the control vials 0.1ml of the culture was added after lOOfold dilution of the initial inoculum. Stock solution of lmg/ml of each compound was prepared in DMSO in separate sterile tubes. The compounds were further diluted to concentration of 25 ^g/100 ul, 0.1ml was than added to the 7H12B vial containing mycobacterial culture so that final concentration of the compound 6.25 u.g/ml. The cap in all the vials were cleaned with isopropanyl alcohol and kept in racks. The vials were then incubated at 37°C without shaking. Test vials was read daily on the BACTEC system till the GI of the control vial reached > 30.Once the GI in the control reached 30 AGI (GI = GI (n> - GI („.i) ) was determined for all test and control vials. If AGI of test vial is less than that of the control vial the culture was sensitive to the test compound. in vitro Agar Dilution assay MIC of compound of formula (I) of this invention against strains of Mycobacterium were determined by a reference agar dilution method as per the NCCLS- M24-T2. recommendations. The compounds were dissolved in DMSO and diluted twofold to obtain ten serial dilutions of each compound. Appropriate volume of compounds were incorporated into duplicate plates of Middlebrook7H10 agar medium supplemented with 10% Middlebrook supplement oleic acid-albumin-dextrose (OADC) enrichment at concentration of 0.03u,g/ml to 16\|j,g/ml. Test organisms (mycobacterium strains) were grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement. After 7 days of incubation at 37°C the broths were adjusted to the turbidity of 1.0 McFarland standard; the organism were further diluted 10 fold in sterile water containing 0.10% Tween-80. The resulting mycobacterial suspensions were spotted (3-5jxl/spot) onto drug supplemented 7H10 media plates. The plates were sealed and incubated at 37°Cfor 3-4 weeks in upright position. The MIC was recorded as the lowest dilution of the drug that completely inhibited the growth of test organisms. Test isolates included 10 clinical isolates that were generally susceptible to common tubercular agents and 10 strains that were resistant to one or more standard anti tubercular drugs. Appropriate reference strains and control drug was included in each batch of test. 42 in vivo studies: The efficacy of the compound of formula (I) of this invention was also evaluated in murine model of pulmonary tuberculosis. Mycobacterium tuberculosis cultures grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement at 37°C for 7 days on a rotary shaker. For, animal inoculation liquid cultures were declumped by brief sonication and were diluted appropriately in 7H9 broth to obtain a concentration of lxl07CFU's/ 0.2ml. Four-week-old male outbred Swiss albino mice housed in a pathogen free, biosafety level 3 environment within micro isolator cages were used throughout the study. Infections were produced by intravenous inoculation into caudal tail vein of 0.2ml of declumped M. tuberculosis suspension. Following infection, mice were randomly distributed in different groups of six each. Treatment for initial study was started one day after infection. For, treatment Compound No. 30 of formula I was dissolved in 10% PEG. Isoniazid was dissolved in sterile water. The drugs were prepared each morning prior to administration. Therapy was given 5 days per week for four weeks. All the agents were administered by gavage and were dosed at 50,25,12.5mg / kg of body weight. Control group of infected but untreated mice were killed at the initiation of therapy (early control) or at the end of the treatment period (late control). Mice were sacrificed by cervical dislocation 3-5 days after the administration of the last dose of drug. The spleens and right lung were removed aseptically and homogenized in tissue homogeniser. At least 4 serial tenfold dilution of the homogenate was plated onto selective Middlebrook 7H11 agar plates in duplicate. The colony counts were recorded after incubation at 37°C for 4 weeks. The viable cell counts were converted to Logio values. A compound showing 2 Log reduction in viable counts compared to the controls was considered significant. The in vivo data for a representative compound of formula (I) is given in Table-II. Acute toxicity of Compound No. 30 of Chart-I was estimated in mice and the LDo was found to be >1000 mg/kg P. O. 43 Table-I: in vitro activity of compounds 1 to 58 of formula (I), Compound No. Growth inhibition of M.tuberculosis 27294 MIC (fig/ml) against M.tuberculosis 27294 Clinical isolates Sensitive Resistant 1 + 16 4-16 >16 2 + 8 8 8 8 + 2 .5-2 2-4 13 + 2 2 2-4 14 + 0.25 0.25-0.5 4->16 15 + >16 >16 >16 16 + 0.5 0.5 0.5(>16) 17 + 0.5 1.0 0.5-1.0 18 + 4- 1-4 8->16 19 + 2 1-2 2 20 + 1 1-2 2-4 21 + 0.5 0.5-2 0.5(>16) 25 + 4 4-16 4->16 27 + >16 >16 >16 28 + 0.5 1-2 2-8 30 + 0.5 0.5 0.5-2 31 + 1 1-2 1-4 32 + 0.25 0.25-0.5 4-(>16) 33 + 0.5 1 0.5-2 34 + >16 >16 >16 35 + 4 2-4 4-8 36 + 4 4-8 4-8 44 Table-I Contd.... 39 + 2 2-4 2-8 40 + 1 1-2 1-2 43 + 1 0.5-1.0 1-2 44 + 1 0.5-2 1-4 45 . + 2.0 2-4 2-4 46 + 2 2-4 2-8 47 + 1 1-2 2-4 48 + 2 2-4 2-8 49 + 4 4-16 4-16 50 + 2 2-4 2-4 51 + 8 8->16 8->16 52 + 2 2 4->16 53 + >16 >16 >16 54 + 8 8-16 >16 55 + >16 >16 >16 56 + >16 >16 >16 57 + 16 16->16 >16 58 + 8 8-> 16 8-> 16 Isoniazid + 0.25 0.12- .25 8 - >16 Linezolid + 0.5 0.25-0.5 1.0-2.0 Table-II MIC values of compound of formula (I) against different species ofMycobacteria Sr. No. Compound No. MIC (ug/ml) M. tuberculosis M.avium- intracellular complex M.fortuitum M.kansai Sensitive Resistant 1 Compound 30 of formula I 0.50 0.50-2.0 8.0->16.0 >16.0 8.0 2 Isoniazid 0.25 4.0-> 16.0 8.0->16.0 >16.0 >16.0 45 Table-m in vivo activity of Compound of formula (I) against M. tuberculosis ATCC 27294" infection in Swiss albino mice Sr. No. Drug& Dose b (mg/kgday" ') or group Mean Logio No. of CFU Mean Logio No. of reductionc Lung Spleen Lung Spleen 1 Compound 30 of Chart-I 50mg/kg 25mg/kg 12.5mg/kg 2.12 2.21 4.34 2.09 2.13 4.30 2.40 2.30 0.20 2.53 2.49 0.26 2 Isoniazid 50mg/kg 25mg/kg 12.5mg/kg 2.03 2.11 2.95 1.92 2.11 2.94 2.49 2.41 1.57 2.70 2.51 1.68 3 Infected early control 4.52 4.62 4 Infected late control 6.57 6.37 a- inoculation of logio:- 7.00 Mycobacteria. b- mice were dosed 5 day/week for 4 weeks. From day 1 -28. c- difference in mean logio number CFU from that of early controls. The compound of formula I of this invention may be administrated to a subject such as a human being or an animal in need of such an administration through any route appropriate to the condition to be treatede. Suitable routes of administration include oral, rectal, nasal, topical (both buccal and sublingual), vaginal and parenteral (including subcutaneous, intramuscular, intradermal, intrathecal and epidural). Pharmaceutical compositions of compound of formula I can be prepared in adjunction with inert pharmaceutically acceptable carriers, which can either be solid or liquid. Solid form preparations include powders, tablets, dispersible granules, capsules, cachets, suppositories and ointments. The solid carriers can be one or more substances which may act also as diluents, flavouring agents, solubilisers, lubricants, suspending agents, binders or tablet disintegrating agents. It can also be finely divided solid which is in admixture with finely divided active compound. Suitable solid carriers are lactose, pectin, dicalcium phosphate, microcrystalline cellulose, sucrose, kaolin, dextrin, gelatin, starch, tragacanth, low melting wax, coca butter and the like. Liquid preparations include solutions, suspensions and emulsions, e.g. solutions of compound of formula I in water or water-propylene glycol mixture for parenteral injection. Liquid preparations can also be formulated along with non-ionic surfactants and edible oils such as corn, peanut and sesame oils. Aqueous solutions for oral use can be prepared by dissolving the active component in water and adding suitable colorants, flavours stabilizing and thickening 46 agents, as required. Aqueous suspension for oral use can be made by dispersing the finely divided active component in water with a viscous material, e.g. natural or synthetic gums, resins, methyl cellulose, sodium carboxymethyl cellulose and othe known suspending agents. The adjuvants may also include preserving agents and anti-oxidants. Compositions for topical application may take the form of liquids or gels, containing a therapeutically effective concentration of compound of formula I admixed with a dermatologically acceptable carrier. The pharmaceutical preparations may be in unit dosage form. In such form, the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage can be in the form of tablets, capsules, powdersin vials or ampoules, ointments, gels, creams or any other form. The quantity or concentration of the active compound in such unit dose preparations may be varied or adjusted according to the particular application and potency of the active ingredient. 47 A compound of formula (I) and its pharmaceutical^ acceptable salts wherein, A is either hydrogen or fluorine, B is either hydrogen or fluorine, A and B together is hydrogen and fluorine, Ri is a group of formula, wherein, Q is either an alkyl group of two carbon atoms, an alkene group of two carbon atoms or an alkyne group of two carbon atoms Y is oxygen, sulfur or an amino function of formula NR3 wherein, R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or branched; cycloalkyl of 3-7 carbon atoms; CHO, -COOH, -COOR,; COCR,; CN; aryl or heteroaryl wherein, Rt is an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon atoms. Ar is a substituted phenyl ring or a substituted pyridine ring of formula —O-R3 or Ar is a five membered ring of formula 48 or Ar is a fused bicyclic phenyl or pyridine ring of formula wherein, M is either CH or N Z is CH, NH, O, or S, X is a group selected from OR,, NR4R5, N02, SR,, SOOR,, SOONR4R5, F, CI, Br or I, wherein R4 is as defined hereinbefore, and and R3 is as defined hereinbefore R5 is hydrogen or R4 R2 is selected from the groups shown below, and the corresponding N-oxides thereof. A compound according to Claim 1 wherein in said compound of formula I Aryl is phenyl substituted with (0) or (1) of F, CI, "OCH3, "OH, "NH2, CrC4 alkyl, 0-C(0)-OCH3," N02or"CN. 49 3. A compound according to Claim 1 wherein said compound of formula I is selected from the group consisting of: 1) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 2) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 3) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 4) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide. 5) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 6) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 7) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide. 8) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 9) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide. 10) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 11) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide. 12) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide. 13)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 14) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide. 15) (S) - N -[ [ 3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide. 16) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl 1 methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide. 17) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 50 18) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 19) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl]-4-oxo-4-(2-thienyl)butanamide. 20) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 21)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide. 22) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 23) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 24) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 25) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 26) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) — 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 27) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 28) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide. 29) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide. 30) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide. 31)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (2 - thienyl)butanamide - N - oxide. 32) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide. 33) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N -oxide. 34) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 51 35) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4- oxobutanamide. 36) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4- oxobutanamide. 37) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4- oxobutanamide. 38) (S) - N -[ [ 3 - (3 - fluoro - 4 - benztriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 39) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 40) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide. 41) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4 - oxobutanamide. 42) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide. 43) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 44) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide. 45) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 46) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 47) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide. 48) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide. 49) (S) - N .-[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 50) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 51) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide. 52) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide. 52 53) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide. 54) (S) -N-[[3-(3- fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 55) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 56) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -■ ( 4 - thiomethylphenyl )butanamide. 57) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2 - naplrthyl) - 4 - oxobutanamide. 58) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide. 59) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 60) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 61)(S)-N-[[3-(3- fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 62) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide. 63) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide. 64) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide. 65) (S) - N -[ [ 3 - ( 5 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 66) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (4 - thiomethylphenyl)butanamide. 67) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 68) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide. 69) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide. 70) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide. 53 71) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 72) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 73) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide. 74) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide. 75) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide. 76) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) --2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2 - naphthyl) - 4 - oxobutanamide. 77) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - '2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide. 78) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide. - ' 4. A compound as claimed in claim 3 wherein said compound of formula I is selected from the group of N-oxide of the said compounds 1 to 78. 5. A pharmaceutical composition comprising a) atleast one of I) any compound of claims 1 to 4 and II) its pharmaceutically acceptable salts and b) a pharmaceutically acceptable carrier. 6. A pharmaceutical composition according to claim 5 comprising a solid or liquid preparation. 7. A pharmaceutical composition as claimed in anyone of claims 5 to 6 for oral or parenteral administration. 8. A method of preparation of the compound of formula I and/or its pharmaceutically acceptable salts comprising: coupling of the amino fragment of compound of formula II 5^ (II) with a carboxylic acid of formula III in the presence of an acid activating group or a dehydrating agent in a suitable solvent. (Ill) wherein R2 has the same meaning as given in claim 1. 9. A method as claimed in claim 8 wherein the compound of formula II is preferably selected from (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine,(S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, S) - N -[3 - (3 - fluoro - A - benzotriazolylphenyl) - 2 - oxo - 5 -oxazolidinyl] methyl amine, and (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine. 10. A method as claimed in anyone of claims 8 or 9 wherein the compound of formula III is selected from 4-(2-Naphthyl)-4-oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic acid, 4-oxo-4-(2' methy lpropyl)phenylbutanoic acid, 4-Oxo-4-(2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 - 5S oxobutanoic acid,4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, . 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 - phenyl - but - 2 - ynoic acid. 11. A compound of formula I, its pharmaceutically acceptable salts and pharmaceutical compositions obtained thereof substantially as herein described and illustrated. Dated this 5th day of March 2005 Dr. Sanchita Ganguli Of S. MAJUMDAR & CO. Applicants' Agent 5t

Full Text

F0RM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. - OXAZOLIDINONE DERIVATIVES, PROCESS FOR THEIR
PREPARATION AND THEIR USE AS ANTIMYCOBACTERIAL AGENTS
2. Applicants)
(a) NAME : LUPIN LIMITED
(b) NATIONALITY : An Indian Company
(c) ADDRESS : 159, C.S.T. Road, Kalina, Santacruz (East),
Mumbai - 400 098, Maharashtra, India
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed

FIELD OF THE INVENTION
The present invention relates to novel compounds belonging to the class of oxazolidinones useful in the treatment of acid fast organisms such as Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium spp. The present invention further relates to methods for preparation of the novel compounds and to pharmaceutical compositions containing the novel compounds useful in the treatment of tuberculosis. BACKGROUND OF THE INVENTION
Tuberculosis (TB), an infectious disease caused by the bacterium Mycobacterium tuberculosis is transmitted mainly through air, affecting most often the lungs. When persons with pulmonary TB cough they produce tiny droplet nuclei containing M. tuberculosis, which remain suspended in air for a prolonged period of time. A person who breathes the air containing the aforesaid droplet nuclei containing M. tuberculosis can become infected with TB.
TB, one of the three major infectious diseases in the priority list of the World Health Organization's (WHO) agenda kills about two million people around the world every year. About six million new cases are reported every year and nearly 20% of adult deaths and 6% of infant deaths are attributable to the disease (C. Dye et. al., J. Am. Med. Ass., 1999, 282, 677-686). About a billion people are expected to be affected by TB by the year 2020, with 35 million likely to succumb to the disease (WHO Fact Sheet No. 104, Global Alliance for TB Drug Development- Executive Summary of the Scientific Blueprint for TB Development : http://www.who.int/inf-fs/en/factl04.html).
With the emergence of the AIDS epidemic and the increase in cases of HIV coupled with TB as well as the continued resistance of M. tuberculosis to isoniazid and rifampicin, the two most powerful anti-tubercular drugs available today there is an urgent need for new anti-tubercular drugs to combat the killer disease (S. H. E. Kaufmann et. al., Trends Microbiol., 1993, 1,2-5 ; B. R. Bloom et. al., N. Engl. J. Med., 1998, 338, 677-678).
Although, many new compounds are becoming available for fighting a number of infectious diseases, the number of such compounds having antimycobacterial activity are few. This could partly be due to the complexity of research involved and partly due to business considerations (B. N. Roy et. al., J. Ind. Chem. Soc, April 2002, 79, 320-335 and references cited therein).
However, renewed thrust in research in the last decade has resulted in development of new antimycobacterial compounds,
a) differing widely in structures,
b) having different mode/mechanism of action,
c) possessing favourable pharmacokinetic properties,
d) which are safe and have low incidence of side-effects, and
e) which provide a cost-effective dosage regimen.
2

Among the aforesaid new compounds, the oxazolidinones first developed during the mid-1980s (W. A. Gregory et. al., J. Med. Chem., 1989, 32,1673-1681 and 1990,33,2569-2578 ; C-H Park et. al., J. Med. Chem., 1992, 35, 1156-1165) are a unique class in themselves. The in vivo results for some of the oxazolidinones show that they are active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, including resistant strains such as methicillin-resistant Staphylococcus aureus [MRSA], methicillin-resistant Streptococcus epidermidis [MRSE], penicillin-resistant Streptococcus pneumoniae [PRSP], vancomycin-resistant enterococci [VRE], etc. (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999,9 (5), 625-633 and the references contained therein).
The oxazolidinones inhibit bacterial protein synthesis at a very early step in the initiation of complex formation involved in the process of translating mRNA into protein. The oxazolidinones, in general, are not cross-resistant with any known antibiotic because of this unique mechanism (D. C. Eustice et. al., Antimicrob. Agents Chemother., 1988, 32, 1218 and Biochem. Biophys. Res. Commun., 1988,150. 965).
A feature of the oxazolidinone molecule is that only those compounds, which are enantiomers with a (5S)-acetamidomethyl configuration in the left side of the molecule are known to exhibit antibacterial activity (W. A. Gregory et. al., J. Med. Chem., 1989, 32, 1673-1681). Another feature is that most of such antibacterial compounds invariably carry a (substituted) phenyl ring attached to the nitrogen atom of the oxazolidinone ring in the right side of the molecule (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999, 9 (5), 625-633 and the references contained therein).
The most promising compound among the N-phenyl oxazolidinones, which has been approved for human use is (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidin-yl]methyl]-acetamide), commonly known as linezolid (M. Barbachyn et. al., WO 995/07271). Linezolid possesses good in vitro and in vivo potency against most of the Gram-positive bacteria, including resistant strains {Drugs of the Future, 1996,21.(11), 1116-1123).
The left hand side i. e. position 5- and the right hand side i. e. position 3- respectively of
the oxazolidinone ring nucleus allows for many variations and has resulted in the discovery of a
large number of compounds having antimicrobial and antibacterial properties. Such
representative compounds, albeit not meant to be limiting are disclosed in the following prior art
references. These are:
i) US 4,942,183 (Gregory et. al.) and US 4,948,801 (Carlson et. al.) collectively disclose
certain 3-substituted phenyl- 5-aminomethyl oxazolidinones, possessing useful
antibacterial activity, ii) US 5,529,998 (Habich et. al.) discloses certain 3-benzoxazoyl- and benzothiazolyl-5-
acetyl amino methyl oxazolidinones, useful as antibacterial medicaments.
3

iii) US 5,565,571, US 5,654,428, US 5,756,732, US 5,801,246 and US 5,929,248 (Barbachyn et. al.) collectively disclose several substituted aryl and heteroaryl phenyloxazolidinones carrying an acetyl aminomethyl function at the 5-position, specifically oxazolidinones having an aryl or heteroaryl group at the para position of the 3-phenyl ring and additional substituents at the meta positions of the 3-phenyl ring, which are useful as antibacterials.
iv) US 5,652,238 (Brickner et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a hydroxyl acetyl piperazine moiety, active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, as well as anerobic organisms such as bacteroides and Clostridia species as well as acid-fast organisms such as Mycobacterium tuberculosis.
v) US 5,684,023 (Riedl et. al.) discloses certain 3- benzofuranyl- and benzothienyl oxazolidinones, carrying an azido, hydroxy or acetyl aminomethyl group at the 5-position, useful as antibacterial medicaments.
vi) US 5,688,792 (Barbachyn et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a (substituted)-morpholine. Such compounds are useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp.
vii) US 5,719,154 (Tucker et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the said substitution being a pyrimidinyl or pyradazinyl group. Such compounds are useful as antimicrobial agents.
viii) US 5,736,545 (Gadwood et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a five membered heterocycle ring, in particular an azolyl ring. Such compounds are useful in the treatment of microbial infections.
ix) US 5,792,765 (Riedl. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-substituted phenyloxazolidinones, the substitution being a heterocyclic moiety, useful as antibacterial medicaments.
x) US 5,861,413 (Habich et. al.) discloses certain 2-oxo and 2-thio-l,2-dihydroxyqoinolinyl-1-oxazolidinones, useful as antibacterial medicaments.
xi) US 5,880,118 (Barbachyn et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a
4

substituted thiomorholine moiety i. e. oxazine and thiazine derivatives, useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp.
xii) US 5,910,504 and US 6,124,334 (Hutchinson et. al.) collectively disclose certain substituted 5-acetyl aminomethyl-3- phenyloxazolidinones substituted at the para position of the 3-phenyl ring with a heteroaromatic moiety, which is five membered having one to four nitrogen atoms or alternatively, a benzoannulated five-membered heteroaromatic ring having one to four nitrogen atoms, useful as antibacterials.
xiii) US 6,069,160 (Stolle et. al.) discloses certain substituted 5-acetyl aminomethyl-3-benzocyclopentaneoxazolidinones, containing an heteroatom, useful as antibacterial medicaments.
xiv) US 6,227,868 Bl and US 6,410,728 (Sciotti et. al.) collectively disclose certain 5-acetyl aminomethyl-3-phenyloxazolidinones carrying an acetylenic moiety on the 3-phenyl ring, useful for treating bacterial infections, psoriasis, arthritis and toxicity due to chemotherapy.
xv) WO 93/23384 (Hutchinson et. al.) discloses certain substituted 5-acetyl aminomethyl-3 -phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, useful for treatment of microbial infections caused by staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium.
xvi) WO 97/10223 (Gadwood et. al.) discloses certain substituted 5-acetyl aminomethyl-3-aminoaryl oxazolidinone N-oxide compounds, which are exceedingly water soluble and useful in preparation of pharmaceutical compositions for combating a number of human and veterinary pathogens, staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium, Mycobacterium spp. and Mycoplasma spp.
xvii) WO 98/01446 and WO 98/01447 (Betts et. al.) collectively disclose certain substituted 5-acetyl aminomethyl3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a six-membered heteroaryl ring containing two or three ring nitrogen atoms as the only ring heteroatoms, useful as antibacterial agents.
xviii) WO 99/02525 (Thomasco et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted by a thiadiazolyl or oxadiazolyl moiety, useful as
5

antimicrobial agents, effective against a number of human and veterinary pathogens, including Gram-positive and Gram-negative aerobic bacteria.
xix) WO 99/37630 (Gordeev et. al.) discloses oxazolidinone combinatorial libraries, compositionscontaining the same and methods of preparation thereof involving solid phase synthesis, which provides the said compounds for high-throughput screening.
xx) W099/37641 (Bartel. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-bicyclene-substituted oxazolidinones, useful as antibacterial medicaments.
xxi) WO 01/09107 (Gordeev et. al.) discloses certain 3-heteroaryl-5-acetyl aminomethyl oxazolidinones, substituted by a thioacyl, aminocarbonyl, alkoxycarbonyl, aminothiocarbonyl, alkoxythiocarbonyl and alkylthiocarbonyl group, useful in treating or preventing an infectious disorder in humans or animals.
xxii) WO 01/42242 (Paget et. al.) discloses certain substituted 5-acetyl aminomethyl 3-substituted phenyloxazolidinones, the substitution being a bicyclic heterocyclic system, useful as antibacterial agents.
xxiii) WO 02/06278 (Mehta et. al) discloses certain substituted 3-phenyl oxazolidinones and to process for synthesis of the same, the said compounds useful as antibacterial agents, effective against a large number of human and veterinary pathogens, including Gram-positive bacteria and acid fast organisms such as Mycobacterium tuberculosis.
xxiv) WO 02/20515 (Madar et. al.) discloses heterocyclic phenyloxazolidinones, useful for treating bacterial infections. However, only a few of the disclosures described hereinbefore provide compounds that
can be used as antimycobacterials, while most of the others are silent about the antimycobacterial
activity of the disclosed compounds.
A need, therefore, exists for new compounds possessing potent antimycobacterial
properties for treatment of TB, which as mentioned hereinearlier is assuming alarming
proportions.
OBJECTS OF THE INVENTION
It is thus the basic object of the present invention to synthesize, identify and provide new
compounds belonging to the class of oxazolidinones, possessing potent antimycobacterial
properties especially for treatment of acid fast organisms such as Mycobacterium tuberculosis,
Mycobacterium avium-intracellular complex, M. fortuitum and M. kansai.
Another object is directed to providing antimycobacterial pharmaceutical composition
effective in inhibiting/treating the generation of mycobacterial conditions/cells including
Mycotacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M fortuitum and Mkansai.
6

Yet another object is directed to providing a method of treating/inhibiting mycobacterial cells/conditions involving the administrations of effective amount of the novel antimycobacterial compound and/or its salts /composition of the invention. SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention there is provided compound of formula (I) and its pharmaceutically acceptable salts thereof

wherein,
A, B = H, and/or F Ri is a group of formula

wherein,
Q is CH2-CH2, CH=CH, or C=C
Y is O,S or NR3
wherein,
R3 is Ci - C4 alkyl (straight, branched, unsaturated), cycloalkyl, COOH, COOR,, CHO, COCR4,
CN, aryl, heteroaryl
wherein,

R is an alkane of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon
atoms, and
Ar is an aromatic carbocycle represented by

7

wherein,
X is OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, Br, CI, F, or I,
M is-CHorN,and
Zis-CH,-NH,OorS
and wherein,
R3 and R4 are as described hereinbefore, and
R5 is H, or same as R4, and
R.2 is selected from the groups shown below, and the corressponding N-oxides thereof

Heteroaryl or Heterocycloalkyl wherein K is O, S, SO, S02, or CH2
According to another aspect of the invention there is provided a pharmaceutical
composition comprising:
i) atleast one of an antimycobacterially effective amounts of compound of formula I and
pharmaceutically acceptable salts there of; and ii) a pharmaceutically acceptable carrier.
According to yet another aspect of the present invention there is provided a method of inhibiting growth of mycobacterial cells such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M.kansai.,comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof.
8

According to yet another aspect of the present invention there is provided a method of treating mycobacterial conditions such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M kansai, comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof.
According to another aspect, there is provided a process for the manufacture of the compound of formula I or its pharmaceutically acceptable salts comprising : coupling the amino fragments of compound of formula II with the carboxylic acid fragment of formula III.
The above disclosed compound of formula I its pharmaceutically acceptable salts thereof are found to have antimycobacterial properties and the same in admixture with pharmaceutically active additives, an be administrated orally or paranterally for treatement of mycobacterial conditions especially TB. DETAILED DESCRIPTION OF THE INVENTION
In the pharmaceutically active compound of formula (I) of this invention,

the definition of the symbols and groups A, B, Rt and R2 are as follows :
A is either hydrogen or fluorine,
B is either hydrogen or fluorine,
A and B together is hydrogen and fluorine,
When A is hydrogen, B is fluorine and vice-versa.
R1 represents a group of formula,

Q is either an alkyl group of two carbon atoms (CH2-CH2), an alkene group of two to carbon atoms (CH=CH), or an alkyne group of two carbon atoms (C=C)
9

Y can either be oxygen, sulfur or an amino function of formula NR3, wherein
R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or
branched. Suitable alkyl groups are methyl, ethyl, n-propyl, n-butyl, iso-propyl, iso-butyl, tert-
butyl, ethylene, propylene, 1, butene, both the geometric isomers of 2-butene i. e.(cis)-2-butene
and (trans)-2-butene, and iso-butylene. or
R3 is a cycloalkyl group of 3-7 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl,
cyclohexyl and cycloheptyl, or
R3 is a carboxylic acid group (-COOH) or a carboxylic acid ester of formula-COOR4, wherein
R4 is H, an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6
carbon atoms.
R3 is further an aldehyde (-CHO), an acetyl group (-COCR4), wherein R4 is as mentioned
hereinbefore or R3 is a nitrile (CN), aryl or heteroaryl, wherein
Aryl is phenyl substituted with (0) or (1) of-F, -CI, -OCH3, -OH, -NH2, -CrC4 alkyl, -O-C(O)-
OCH3,-N02or-CN,and
Heteroaryl
or Ar is a five membered ring of formula
or Ar is a fused bicyclic phenyl or pyridine ring of formula
10
The group Ar is a substituted phenyl ring or a substituted pyridine ring of formula

wherein,
M is either CH or N; Z is -CH, -NH, O or S and R3 is as defined hereinbefore,
X is a group selected from OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, F, CI, Br or I, wherein
R4 is as defined hereinbefore, and
R5 is hydrogen or R4.
R2 is selected from the groups shown below, and the corresponding N-oxides thereof.

Heteroaryl or Heterocycloalkyl
wherein K is O, S, SO, S02, or CH2
The preferred novel compounds of formula (I) that form part of this invention, are as follows.
The following compounds 1 to 78( named as per IUPAC or CAS nomenclature) are preferred compounds of formula (I) of the invention.
1. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide.
2. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
3. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
4. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide.
5. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
11

6. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide.
7. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide.
8. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
9. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
10. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ]
- 4 - oxo - 4 - phenylbutanamide.
11. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methylphenyl) - 4- oxobutanamide.
12. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - (4 - methylphenyl) - 4- oxobutanamide.
13. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
14. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide.
15. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide.
16. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide.
17. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
18. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
19. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide.
20. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - (2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
21. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide.
22. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
23. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
12

24. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazohdinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
25. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazohdinyl methyl] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
26. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazohdinyl ] methyl
- 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide.
27. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
28. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl
- 4 - oxo - 4 -( 2 - thienyl)butanamide.
29. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide.
30. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide.
31. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide.
32. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide.
33. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N - oxide.
34. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
35. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methoxyphenyl) - 4- oxobutanamide.
36. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - chlorophenyl) - 4- oxobutanamide.
37. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2,4 - dimethylphenyl) - 4- oxobutanamide.
38. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benztriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
39. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
40. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
41. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
13

42. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
43. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide.
44. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide.
45. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
46. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
47. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide.
48. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide.
49. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
50. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
51. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
52. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 -( 2 - thienyl)butanamide.
53. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
54. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
55. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - phenylbut - 2- enamide.
56. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - oxo- 4 - ( 4 - thiomethylphenyl )butanamide.
57. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - (2 - naphthyl) - 4 - oxobutanamide.
58. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide.
59. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
14

60. (S) - N -[ [ 3 - (3 - fluoro—4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
61. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbut - 2- enamide.
62. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
63. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide.
64. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide.
65. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
66. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - (4 - thiomethylphenyl)butanamide.
67. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - ( 2 - naphthyl) - 4 - oxobutanamide.
68. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
69. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide.
70. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
71. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
72. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
73. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
74. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
75. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
76. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
77. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
15

78. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 — oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide.
The respective N-oxides of the group R2 of the compounds of formula I listed above also form a novel aspect of the present invention.
The pharmaceutically active compounds of formula (I), the corresponding N-oxides of the group R2 and pharmaceutically acceptable salts thereof of this invention can be prepared by methods known to one skilled in the art.
Typically, compounds of formula (I), can be prepared by coupling of the amino fragment of formula (II)

Scheme-!
General method for synthesis of compounds of formula (I)

In a typical experiment, the amine compound of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinbefore is dissolved in a 1:1 mixture of tertahydrofuran and water or a 1:1 mixture of methylene chloride and water. To the solution is added the carboxylic acid compound of formula (III), followed by addition of 1-hydroxybenztriazole (HOBt). The resulting mixture is cooled to a temperature of 0-5° C to which l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 1.1 Eq.) is added and gradually allowed to warm to room temperature and agitated at this temperature for 24 hours. At the end of
17

the reaction, a solution of saturated aqueous sodium bicarbonate is added and the organic phase separated from the aqueous phase. Evaporation of the solvent and chromatography of the residue over silica gel affords compound of formula (I), generally as white solids.
The N-oxides of the group R2 of compound of formula (I) thus obtained are preferably prepared by addition of m-chloro perbenzoic acid (m-CPBA) to a cooled solution of the compound of formula (I) in a chlorinated hydrocarbon solvent such as methylene chloride and ethylene chloride and thereafter agitating the reaction mixture at room temperature for 12-15 hours. Evaporation of the solvent under reduced pressure, followed by chromatography of the residue over silica gel affords the corresponding N-oxides in high purity.
The N-oxides thus prepared, while retaining most of the antimycobacterial activity of the corresponding deoxo compound exhibit exceedingly high water solubility over the deoxo analogue, thereby helping in manufacture of suitable iv formulations, which forms an important aspect of this invention.
The starting materials required for synthesis of compound of formula (I), thus involve the amine compound of formula II and the carboxylic acid compound of formula III.
The amine compound of formula II can be selected from i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, vi) (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, and viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 -
oxazolidinyl] methyl amine.
18

The carboxylic acid compound of formula III can be selected from 4-(2-Naphthyl)-4-
oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic
acid, 4-oxo-4-(2'methylpropyl)phenylbutanoic acid, 4-Oxo-4-
(2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 - oxobutanoic acid,4 - (2,4 -
dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4-
chlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid,
4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 - phenyl - but - 2 - ynoic acid.
20

Thus, the starting amines of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinearlier are prepared as per the method disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33, 2569-2578; C. Wang et. al., Tetrahedron, 1989, 45, 1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO 95/25106 and WO 97,21708. The method is essentially summarized in Scheme-II.

In a typical method, morpholine, thiomorpholine, piperidine, 4-benzyl piperazine, pyrrolidine, 1,2,4-triazine, 12,3-benzotriazine, benzyl amine, a heterocycloalkyl or a heteroaryl moiety etc., each one of which corresponds to the group R2 defined hereinbefore is reacted with 3,4-difluoro nitrobenzene in the presence of a base and a solvent to give the corresponding derivative in which the fluorine atom at 4-position is substituted by the group R2. The nitro group in the compound thus obtained is reduced to amino group, which is thereafter protected by a suitable protective group. Reaction of the N-protected compound thus obtained with (R)-glycidyl butyrate in the presence of a strong base like n-butyl lithium leads to formation of the 5-hydroxymethyl oxazolidinone ring. The hydroxy group in the compound thus obtained is converted to sulfonyl derivative, for e.g. a methanesulfonyloxy (mesyl) or a p-toluenesulfonyloxy (tosyl) derivative by reaction with methanesulfonyl chloride or p-toluenesulfonyl chloride respectively. Reaction of the respective mesyl or tosyl derivative with sodium azide gives the corresponding azide, which is converted to the amine compound of formula (II) by standard methods, for e.g. by reaction with a triaryl/trialkyl phosphine, followed by hydrolysis.
The starting carboxylic acid fragments of formula (III), wherein the group Ar has the same meaning as defined hereinearlier are prepared as per the method disclosed in Org. Reactions, 1949, 5, 229-289; Quart. Rev. Chem. Soc, 1954, 8, 355-379; Chem. Rev., 1955, 55, 229-281, and J. Am. Chem. Soc, 1947, 69, 1784-1786. The method is essentially summarized in Scheme-HI.
Scheme-Ill General method for synthesis ofalkane and alkene carboxylic acid s of formula (HI)

In a typical method, the aromatic compound Ar-H, wherein Ar is as defined hereinbefore is reacted with succinic anhydride in the presence of a Lewis acid, such as anhydrous aluminium chloride and in the presence of an anhydrous solvent and the mixture heated to 100° C to give the carboxylic acid derivatives of formula (HI), wherein Q is alkyl of 1-4 carbon atoms.
23

Similarly, compounds of formula (III), wherein Q is an alkene (CH=CH) are prepared by reaction of the aromatic compound Ar-H, wherein Ar is as defined hereinbefore with maleic anhydride under the same conditions mentioned hereinbefore.
Compounds of formula (III), wherein Q is an alkyne (C=C) are prepared by reaction of propiolic acid ester with an aldehyde of formula Ar-CHO in the presence of butyl lithium and in the presence of an aprotic solvent such as THF at -78° C to give the corresponding secondary alcohol, which is oxidized to the keto derivative using manganese dioxide as the oxidizing agent. Saponification gives the carboxylic acid derivative of formula (ID) [ US 4,929,741 (A. Fischili et. al.) ] The synthesis is summarized in Scheme-IV.

P = any protective group
The synthesis of compound of formula (I) of this invention and the synthesis of the respective starting material amines of formula (II) and the carboxylic acids of formula (III) are further described herein in detail.
SYNTHESIS OF THE STARTING AMINES OF FORMULA OD
The amines were prepared as per the chemistry summarized in the Scheme-H and as per the methods disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33,2569-2578; C. Wang et. al., Tetrahedron, 1989, 45,1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO
24

95/25106 and WO 97,21708. Commercially available raw materials and known techniques were utilized for the synthesis.
The optically pure amines as such were obtained by using optically active intermediates or resolution of racemic mixtures by a suitable reagent. The preferred enantiomer is (S), at the chiral centre on the oxazolidinone ring.
Example 1 General Method for Preparation of the Amines (II)
The oxazolidinone azides of general formula (8), given in Scheme-II (1.0 eq) were dissolved in dry THF (10 times by volume ) and treated with triphenyl phosphine (1.5 eq.) at room temp. The resulting solution was stirred for 6hrs at room temp. Water [2 eq. of (8)] was added and the solution heated for 6hrs at 55 - 60° C. The solvent was evaporated and the residue chromatographed on a column of silica gel (100 -200 mesh) and eluted initially with ethyl acetate and then with chloroform : methanol (4:1) to give the the amines (II) as white solids.
The following amines i) to viii) of formula I were prepared by this general method, viz.
i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, vi) (S) - N -[3 - (3 - fluoro — 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, and
viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 -
oxazolidinyl] methyl amine.
SYNTHESIS OF THE STARTING CARBOXYLIC ACIDS OF FORMULA (HP
Example 2 4-(2-Naphthyl)-4-oxobutanoic acid
Naphthalene (5.0gm, 0.039moles) and succinic anhydride (4.68gm, 0.0468 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (11.44g, 0.0858 moles) was added at
25

room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 25 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid. Subsequent column chromatography gave a buff coloured solid. Subsequent chromatography gave 3.7 gm (41%) the title compound, mp 173-174° C.
'H NMR (CDCI3, 5) : 8.40 (s,lH), 7.7 - 8.0 ( m, 4H), 7.4 - 7.6 (m,2H), 3.33 (t,2H), 2.77 (t,2H + 1H).
The filterate was concentrated to give 5.8 gm of a mixture of 4-(2-naphthyl)-4-oxobutanoic and 4-(l-naphthyl)-4-oxobutanoic acid.
Example 3 4- Oxo-4-(2- ThienylJbutanoicacid
Thiophene (5.0gm, 0.059moles) and succinic anhydride (7.13gm, 0.0713 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (17.43gm, 0.131 moles) was added at room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 30 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (50 ml). The solid was dried at room temp to give 9.8 gm (89%0 of the title compound, mp 103 - 107° C.
!H NMR (CDCI3, 8) : 7.69 (dd, 1H), 7.58 (dd, 1H), 7.07 (dd,lH), 3.9 (bs, 1H), 3.23 (t, 2H), 2.74 (t,2H).
Example 4 4- Oxo-4-(4-thiomethyl)phenylbutanoic acid
Thiophenol methyl ether (8.0gm, 0.0645moles) and succinic anhydride (7.75gm, 0.0774 moles) were taken up in dichloroethane (80 ml). Aluminium chloride (18.90gm, 0.1419 moles) was added at room temperature. The resulting mixture stirred for 0.5hr and then heated at 85° C for lhr. The reaction mixture was cooled to room temperature, diluted with 40 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (80 ml). The solid was dried at room temp to give 6.9 gm (48%) of the title compound, mp 151 -154° C. *H NMR (CDCI3, 5) : 7.82 (d,2H), 7.20 (d, 2H), 4.2 (bs, 1H), 3.21 (t, 2H), 2.73(t, 2H),2.45 (s,3H).
26

Example 5 4 - oxo -4- (2'methylpropyl)phenylbutanoic acid
2'methylpropylbenzene (5.0m, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles), were taken up in dichloroethane (50 ml). Aluminium chloride (10.90g, 0.0821 moles ) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 ml of a 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.7 gm (99%) of the title compound as a solid, mp 102 - 105° C.
!H - NMR (CDC13, 8) : 7.83 (d,2H), 7.17(d,2H), 3.24(t,2H), 2.74(t, 2H), 2.46 (d, 2H), 1.80 (pent., 1H).
Example 6 4 - Oxo - 4 - (2',2'dimethylethyl)phenylbutanoic acid
2',2'dimethylethylbenzene (5.0gm, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (10.90gm, 0.0821 moles) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 m of a 1:1 mixture of water Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.5 gm (97%) of the title compound as a solid, mp 103 — 107° C. !H-NMR (CDCI3,8) : 7.94(d,2H), 7.50 (d, 2H), 3.29 (t,2H), 2.82 (t,2H), 1.36 (s,9H).
Example 7 Using the appropriate aromatic compound (Ar-H) and succinic anhydride and following exactly the method described in Examples 2-6 the following carboxylic acids can be prepared, viz.
i) 4 -(4 -methylphenyl)- 4 - oxobutanoic acid,
ii) 4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid, iii) 4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid, iv) 4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, v) 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, vi) 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid, vii) 4 -{2- Naphthyl)- 4 - oxobutanoic acid, viii) 4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, ix) (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and x) 4 - oxo - 4 - phenyl - but - 2 - ynoic acid.
27

SYNTHESIS OF THE COMPOUNDS OF FORMULA (D
Example 7
Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - J -
oxazolidinyl ] methyl] — 4-(4- naphthyl) -4- oxobutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 dichloromethane-water mixture (10 ml). To this was added 4 -( 2 - naphthyl- 4 - oxobutanoic acid (0.154gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) the resulting mixture was cooled to 0° C. l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added the resulting mixture was allowed to warm to room temperature and then stirred for 24hr. Saturated aqueous sodium bicarbonate solution (2ml) was added to the reaction mixture, stirred for 15 min and then the organic layer separated and the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.22 gm, 64%) as a white solid. MS (M+l) = 506 m/z
*H NMR (CDC13, 5) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, 1H ), 7.01(dd,lH ), 6.74 (t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, 1H), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91 (m,4H), 2.60(t, 2H).
Example 8
Preparation of (S) -N-[[3- (3-fluoro-4-morpholinylphenyl) -2-oxo-5-
oxazolidinyl ] methyl] -4- oxo -4-(2- thienyl)butanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml) . To this was added 4 - oxo - 4 (2 - thienyl)butanoic acid (0.125gm, 0. 00068 moles) and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the resulting mixture was allowed to warm to room temp and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated sodium bicarbonate was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separatedand the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.175 gm, 56%) as a white solid
MS (M+1) = 462 m/z
28

lH NMR (CDC13, 8) : 7.63(d,lH ), 7.55 (dd,lH ), 7.35(dd,lH), 7.04(t, like dd, 2H), 6.83(t,lH), 6.30 (t,lH), 4.69(m,lH), 3.93 (t, 1H), 3.6- 3.8 (m, 3H),3.80 (m,4H), 3.61(dd, 2H), 3.21(dd,2H),2.97 (m,4H),2.55(t, 2H).
Example 9
Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -
oxazolidinyl ] methyl ] - 4 - [4 - ( V- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 -oxo - 5 -oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml). To this was added 4 - [ 4(2'-methylpropylphenyl)]- 4 - oxobutanoic acid (0.158gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated, and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.210gm, 60%) as a white solid.
MS(M=l) = 512m/z
'H NMR (CDC13, 8) : 7.73(d,2H ), 7.52 (dd,lH ), 7.28(m,lH ),7.15(d,2H ), 7.05 (d,lH), 6.39 (t,lH), 4.75(m,lH), 3.91 (m, 4H), 3.5- 3.9 (m, 4H), 3.28 (dd, 2H), 3.16 (m,4H),2.54 (t, 2H), 2.45 (d, 2H), 1.82 (pent., 1H), 2.60 (t, 2H).
Example 10
Preparation of(S) -N-[ [3 - (3 -fluoro -4- morpholinylphenyl) - 2 -oxo - J -
oxazolidinyl J methyl J -4- oxo - 4 -(4- thiomethyl) phenylbutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF -water mixture (20 ml). To this was added 4 - (4-methlythiophenyl) - 4 - oxobutanoic acid (0.152g, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) and the resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142g, 0.00074 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate was added to, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The
29

combined fractions were concentrated to give the title compound (0.270 gm, 79%) as a white solid.
MS (M+l) = 502 m/z
JH NMR (CDC13, 5) : 7.70(d,2H ), 7.37 (dd,lH ), 7.14(d,2H ), 7.00 (dd,lH), 6.79(t,lH), 6.38 (t,lH), 4.71(m,lH), 3.86(t,lH),3.5- 3.9 (m, 4H), 3.81 (m, 4H), 3.22 (dd, 2H), 2.96 (m,4H),2.53 (t, 2H), 2.45(s,3H).
Example 11
Preparation of:. (S) - N-[[3 - (3 -fluoro -4- morphottnylphenyl) — 2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) - 4 - oxobutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.100gm, 0.00034 moles) was taken up in 1:1 THF-water mixture (20 ml) . To this was added 4 - (4- chlorophenyl) - 4 - oxobutanoic acid(0.072g, 0.00034 moles and HOBt (0.046g, 0.00034 moles) .The resulting mixture was cooled to 0°C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.071gm, 0.00037 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated and 2 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with dichloromethane. The organic layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give (0.070gm, 42%) of the title compound as a white solid.
MS (M+l) = 490 m/z
JH NMR (CDCI3, 8) : 7.72(d,2H ),7.37 (dd,lH ),7.31(d,2H ), 6.98 (dd,lH),6.79 (t,lH), 6.28
(t,lH), 4.69(m,lH), 3.83 (t, 1H), 3.81 (m, 4H), 3.4- 3.m (m, 3H), 3.21 (dd, 2H), 2.97 (m,4H),2.54
(t,2H).
Example 12
Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -
oxazolidinyl ] methyl ] - 4 - ( 2 -naphthyl) - 4 - oxobutanamide - N - oxide.
To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -
2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (2 -naphthyl) - 4 - oxobutanamide (0.950gm, 0.0019
moles) in dichloromethane (150 ml) was added 60% m -CPBA (0.550g, 0.0032 moles) and the
resulting solution stirred at room temperature for 12hr. The solvent was evaporated under
reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The
column was eluted with ethyl acetate (200 ml), followed by a mixture of chloroform : methanol
30

(4:1,600 ml).Concentration the combined fractions gave the title N-oxide (0.891g, 82% ) as a
white solid.
!H NMR (CDCI3, 8) : 8.59(t,lH ), 8.36(s,lH),7.7-7.9 (m,5H), 7.2 -7.5 (m,2H),7.08 (dd,lH),
6.60(t,lH), 4.76(m,lH), 4.61(bt,2H), 3.5 - 4.3 (m, 9H), 3.42 (dd, 2H), 2.83 (bdd,2H), 2.61 (bt,
2H).
Example 13
Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide. To a cooled solution (0 - 5° C) of (S) - N -[[3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - oxo - 4 - (2 - thienyl)butanamide (0.850gm, 0.0017moles) in dichloromethane (120 ml) was added 60% m -CPBA (0.550g,0.0032 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The column was eluted with ethyl acetate (200ml) followed by a mixture of chloroform : methanol (4:1,600 ml).Concentration of the combined fractions gave the tile N-oxide (0.790g, 90%) as a white solid.
1HNMR( CDCI3,5) : 8.63(t,lH), 7.77(dd,lH), 7.65 (d, 1H), 7.56 (d, 1H), 7.09 (dd, 1H),7.04 (dd,lH), 6.45(t,lH), 4.68(m,lH), 4.65(bt,2H), 4.22 (dt,2H), 3.89(t,lH), 3.5 - 3.9 (m, 5H), 3.22 (dd, 2H), 3.00 (bd,2H), 2.54 (t, 2H).
Example 14 Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) -4- oxobutanamide -N- oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide, (1.150gm, 0.0023 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.725gm, 0.0040 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1,600 ml). Concentration of the combined fractions gave the title N-oxide (0.950g, 80%) as a white solid.
'HNMRtCDCk 8) : 8.61(t,lH ), 7.76(d,2H), 7.72 (dd, 1H), 7.34 (d, 2H), 7.10 (dd, 1H), 6.46(t,lH), 4.70(m,lH), 4.64(bt,2H), 4.16 (dt,2H), 3.94(t,lH), 3.5 - 3.9 (m, 5H), 3.24 (dd, 2H), 2.97 (bd,2H), 2.55 (t, 2H).
31

Example 15 Preparation of(S) -N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo -5-oxazolidinyl ] methyl] -4-/4-(2'- methyl - 4 -propylphenyl) -4 — oxobutanamide -N-
oxide.
To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - [4 - (2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide (1.05gm, 0.0020 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.600gm) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1 , 600 ml). Concentration of the combined fractions gave the title N-oxide (0.891gm, 82%) as a white solid.
JH NMR (CDC13, 5) : 8.62(t,lH ), 7.77(dd,lH), 7.75 (d, 2H), 7.14 (d, 2H), 7.12 (dd, 1H), 6.44(t,lH), 4.75(m,lH), 4.64(bt,2H), 4.20 (dt,2H), 3.95(t,lH), 3.91 (t,lH) 3.5-3.9 (m, 4H), 3.26 (dd, 2H), 2.99(bd,2H), 2.57 (t, 2H),2.44(d,2H), 0.83(d,6H).
Example 16 Preparation of (S)-N-ff3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4-
methylphenyl)-4-thiooxobutanamide
To a solution of (S)-n- of (S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4-methylphenyl)-4-oxo-butanamide (0.1 Ogm, 0.00021 moles) in dry THF (5ml) was added Lawessons Reagent (0.052gm, 0.000128 moles) and the resulting solution heated under reflux for 8 hr. The reaction mixture was cooled to room temperature and to this was added saturated aqueous sodium carbonate solution (3ml) and then extracted with ethyl acetate. The solvent was evaporated off and the residue chromatographed over silica gel and eluted with a mixture of ethyl acetate-hexane to give the title compound (0.023 gm, 23%) as a white solid, mp 149-151° C.
lH NMR (CDCI3,5) : 8.60 (m, 1H), 7.68 (d, 2H), 7.34 (dd, 1H), 7.14 (d, 2H), 6.96 (dd, 1H), 6.81 (t, 1H), 4.90 (m, 1H), 4.20-4.40 (m, 1H), 3.80-4.0 (m, 4H), 3.50 (m, 2H), 2.90-3.00 (m, 6H).
Example 17 Using the appropriate amine compound (II) and the carboxylic acid (HI) and following exactly the method described in Examples 7-16 the following carboxylic acids can be prepared, viz.
(S) - N-[ [ 3 - (3-fluoro — 4- morpholinylphenyl) -2- oxo — 5- oxazolidinyl J methyl] — 4-(4- methylphenyl) -4- oxobutanamide.
32

'H NMR (CDCI3, 5) : 7.78 (d, 2H ), 7.44 ( d, IH ), 7.22 ( d,2H ), 7.09 ( d, IH ), 6.88 ( t, IH ), 6.41(t, IH), 4.76 (m, IH ), 3.6 - 4.1 (m, 4H ), 3.86 ( m, 4H ), 3.31 ( dd, 2H ), 2.61 (t, 2H ), 2.40 (s.3H).
(S) -N-[[ 3-(3 -fluoro -4 - benzylpiperazinyl) phenyl] -2- oxo - 5 - oxazolidinyl] methy ] -4-oxo -4-phenylbutanamide.
lH -NMR (CDC13, 5) : 7-88 ( d,2H ), 7.61 (dd, IH), 7.38 ( m, 5H ), 7.2 - 7.4 (m, 5H), 6.88 (t, IH ), 6.55 (t, IH ), 4.77 ( m, IH), 3.94 (t, IH), 3.5 - 3.7 (m, 3H ), 3.71 ( s, 2H ), 3.34 (dd, 2H ), 3.12 (m, 4H),3.12 (m, 4H ), 2.61 (t, 2H ).
(S) - N-f]3 - ( 3 -fluoro - 4 - [methylbenzylamin]phenyl) - 2 - oxo -5 - oxazolidiny] methy ]-4-(4- methyl phenyl) -4- oxobutanamide.
*H NMR (CDCI3, 8) : 7.90 ( d, 2H ), 7.52 ( dd, IH ), 7.2 - 7.5 ( m, 8H ), 7.05 ( d, IH ), 6.84 (t, IH ), 6.50 (t, IH ), 4.75 (m, IH ), 4.48 (s, 2H ), 3.95 (t, IH), 3.6 - 4.1( m,3H ), 3.64 ( dd, 2H ), 2.71 (s,3H), 2.62 (t,2H).
(S)-N-[[3-(3-fluoro-4- benzotriazolylpheny)-2-oxo-5-oxazolidinyl]methy]-4-oxo - 4 -phenylbutanamide.
!H NMR ( CDCI3, 5) : 8.16 ( d,lH), 7.84 (d, 2H), 7.66 (t, IH), 7.2 -7.6 (m, 8H), 6.46 (t, IH ), 4.90 (m, IH), 3.98 (t,lH), 3.9 - 4.0 (m, 2H ), 3.65 (m, IH ), 3.39 (ddd, 2H ), 2.65 ( ddd, 2H). (S) -N-[[3-(3-fluoro-4- pyrrolidinylphen) -2-oxo-5- oxazolidinyl]methyl]-4-oxo - 4 -phenylbutanamide.
!H NMR (CDCI3, 8) : 7.90 (d,2H ), 7.52 (dd, IH ), 7.44 (d, 2H ), (dd, IH ), 7.04 (dd, IH), 6.65 (t, IH), 6.43 (t, IH), 4.74 (m,lh), 3.93 (t,lH), 3.77 (t,lH), 3.6 3,8 (m, 2H), 3.33 (m, 6H ), 2.63 (t, 3H), 1.94 (m,4H).
(S)-N-[[3-(3-fluoro-4- benzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methy]-4-(4- methlyphenyl) - 4- oxobutanamide.
!HNMR (CDCU, 8) : 8.16 (d, IH ), 7.3 - 7.9( m,7H), 7.78 (d,2H ), 7.21(d,lH), 6.54(t, IH), 4.89 ( m, IH), 3.8 -42 (m, 3H ), 3.4 - 3.7 (m, 3H ), 2.63 (dd, 2H ), 2.23 (s, 3H ). (S)-N-][3-(3 -fluoro - 4 - thiomorpholinylphenyl) -2 — oxo - 5 - oxazolidinyl] methyl] -4- oxo- 4 -phenylbutanamide.
!H NMR (CDCI3, 8) : 7.89 (d, 2H ), 7.39 - 7.60 ( m, 4H ), 7.11 (dd, IH ), 6.90 (t, IH), 6.39 ( t,lH ), 4.76 (m,lH ), 3.94 (t,lH ), 3.80 (t, IH ), 3.6 - 3.7 ( m, 2H ), 3.36 ( dd, 2H ), 3.28 ( m,4H), 2.80 ( m,4H ), 2.62 (t, 2H).
(S) — N-[[3 - (3 -fluoro - 4 - benzylpiperazinyl) phenyl] — 2 — oxo — 5 - oxazolidinyl] methyl]- 4-(4- methylphenyl) -4- oxobutanamide.
33

*H NMR (CDCI3, 5) : 7.81 ( d, 2H), 7.2 - 7.5 ( m, 8H ), 7.08 (dd, IH ), 6,89 (t, IH ), 6.39 (t, IH
), 4,78 ( m, IH ), 3.95( t, IH), 3.79 (t, IH), 3.6 - 3.7 (ni, 2H ), 3.61(s, 2H), 3.31 ( m,2H), 3.09
(m,4H), 2.65 (m,6H), 2.41 (s, 3H).
(S)-N-[[3-(3-fluoro-4- piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl]-4-
oxo - 4 - phenylbutanamide.
!H NMR (CDCI3, 8) : 7.90(d,2H ),7.60 (dd,lH ),7.45(d,2H ), 7.39 (dd,lH), 7.10 (dd,lH), 6.90
(t,lH), 6.55 (t,lH), 4.78(m,lH), 3.95 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.35 (m, 2H), 3.00
(m,4H0,2.63 (t, 2H), 1.9-1.6 (m,6H).
(S)-N-[[3- (3 -fluoro-4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4-(4
- methylphenyl) - 4- oxobutanamide.
JH NMR (CDCI3, 5) : 7.79(d,2H ),7.40 (dd,lH ),7.23(d,2H ), 7.09 (dd,lH), 6.91 (t,lH), 6.40
(t,lH), 4.77(m,lH), 3.98 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.30(t, 2H), 2.98 (m,4H), 2.62 (t,
2H),2.41(s,3H), 1.6-1.9 (m,6H).
(S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5- oxazolidinyl] methyl]- 4
-(4- methylphenyl) - 4- oxobutanamide.
'H NMR (CDCI3, 8) : 7.80(d,2H ),7.32 (dd,lH ),7.21(d,2H ), 7.01 (dd,lH), 6.60 (t,lH), 6.40
(t,lH), 4.75(m,lH),4.12(m,lH) 3.94 (t, IH), 3.75 (t, IH), 3.4- 3.6 (m, 2H), 3.34 (m, 6H), 2.61 (t,
2H),2.40(s,3H), 1.9(m,4H).
(S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4
-(4- methoxyphenyl) -4- oxobutanamide.
lU NMR (CDCI3, 8) : 7.79(d,2H ),7.36 (dd,lH ), 7.00 (dd,lH), 6.82 (d,2H), 6.80(t,lH), 6.38
(t,lH), 4.69(m,lH), 3.80 (s, 3H), 3.78 (m, 4H), 3.4- 4.0 (m, 4H), 3.20 (dt, 2H), 2.97 (m,4H),2.55
(dt,2H).
(S) -N-[[3-(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-
(2 -naphthyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, IH ), 7.01(dd,lH ), 6.74
(t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, IH), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91
(m,4H), 2.60(t, 2H).
((S) - N -[[ 3 - (3 -fluoro -4- morpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-
(2, 4-difluorophenyl) -4-oxobutanamide.
!H NMR (CDCI3, 8) : 7.73(ddd,2H ), 7.47 (dd,lH ), 7.01(dd,lH ),6.7 - 6.9(m,3H ), 6.30 (t,lH),
4.75(m,lH), 3.89 (m, 4H), 3.5- 3.9 (m, 4H), 3.20 (m, 2H), 3.09(m,4H), 2.52 (t, 2H).
(S)-N -[[ 3-(3 -fluoro -4- morpholinylphenyl) -2- oxo -5— oxazolidinyl] methyl] - 4
-[4- (2s',2'- dimethyl- 4 - ethylphenyl) -4- oxobutanamide.
34

!H NMR (CDC13, 8) : 7.75(d,2H ), 7.37 (d,2H ), 7.35(dd,lH ), 7.05 (dd,lH), 6.82(t,lH), 6.37
(t,lH), 4.71(m,lH), 3.5- 3.9 (m, 4H), 3.80 (m, 4H), 3.25 (dt, 2H), 2.97 (m,4H),2.54 (t, 2H),
1.26(s,9H).
(S) -N-ff 3 - (3 -fluoro - 4 -fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl] -4-(4- methoxyphenyl) -4- oxobutanamide.
lU NMR (CDC13, 8) : 7.76(d,2H ), 7.37 (dd,lH ), 7.16(m,5H ), 6.93 (dd,lH), 6.79(d,2H),6.74 (
t,lH), 6.37 (t,lH), 4.66(m,lH),4.14 (s,2H), 3.84(t,lH), 3.74 (s,3H), 3.4- 3.8 (m, 3H), 3.18 (dd,
2H), 2.62(s,3H),2.5 l(t, 2H).
(S) -N-ff 3 - (3 -fluoro - 4 - fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl]
methy] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide.
'H NMR (CDCU, 8) : 7.77(d,2H ), 7.37 (dd +d,3H ), 7.19 -7.22(m, 3H), 6.98 (dd,lH),
6.77(t,lH), 6.31 (t,lH), 4.69(m,lH), 4.17(s,2H), 3.89(t,lH)„3.72 (dd,lH), 3.5- 3.6 (m, 2H), 3.25
(dd, 2H), 2.64 (s,3H),2.55 (t, 2H), 1.25(s,9H).
(S) -N-ff 3 -(3 -fluoro - 4 -[methylbenzylamino]phenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl] -4- (2,4 - dimethylphenyl) -4- oxobutanamide.
lU NMR (CDCI3, 8) : 7.65(d,lH ), 7.46 (dd,lH ), 7.32(m,5H ), 7.04(m,3H), 6.95(t,lH), 6.36
(t,lH), 4.78(m,lH), 4.27(s,2H), 3.97(t,lH),3.6- 3.8 (m, 2H), 3.81 (t, IH), 3.27 (dd, 2H), 2.77
(s,3H),2.61 (t, 2H), 2.44(s,3H), 2.35 (s, 3H).
(S)-N -[[ 3-(3 -fluoro -4- tnorpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] - 4
- (2,4 - dimethylphenyl) -4- oxobutanamide.
'H NMR (CDCU, 8) : 7.652(d,lH ), 7.42 (dd,lH ), 7.0- 7.1(m,3H), 6.86(t,lH), 6.38 (t,lH),
4.79(m,lH), 3.95(t,lH),3.5- 3.9 (m, 2H), 3.87 (m, 4H), 3.25(dd, 2H), 3.02 (m,4H), 2.59 (t, 2H),
2.41(s,3H), 2.34 (s, 3H).
^ -N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) —2 — oxo -5 — oxazolidinyl] methyl] — 4 —
(2,4 - dimethylphenyl) - 4 - oxobutanamide.
JH NMR (CDCI3, 8) : 7.62(d,lH ), 7.31 (dd,lH ), 7.03(s,+dd, 3H ), 6.60(t,lH), 6.36 (t,lH),
4.74(m,lH), 3.94(t,lH), 3.76 (dd, lH),3.67(m, 2H), 3.30 (m, 4H), 3.24 (dt, 2H), 2.60 (t, 2H),
2.44(s,3H), 2.34 (s, 3H).1.94 (m,2H).
(S) -N-ff 3-(3-fluoro-4- benztriazolylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4-
(2,4- dimethylphenyl) -4-oxobutanamide.
!H NMR (CDCI3, 8) : 8.15(d,lH ), 7.80 (dd,lH ), 7.3 -7.7(m,6H ), 7.02(d,2H), 6.39 (t,lH),
4.87(m,lH), 4.07(t,lH), 3.96(t,lH), 3.89 (dq, IH), 3.75(dt,lH), 3.38 (qt, 2H), 2.62 (m, 2H),
2.39(s,3H), 2.26 (s, 3H).
(S) - N-ff 3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-
oxo -4-(2- thienyl)butanamide.
35

*H NMR (CDC13, 8) : 7.71(d,lH ), 7.63 (d,lH ), 7.31(dd,lH ), 7.11 (t, lH),7.05(dd,lH), 6.68(m,lH), 6.38 (t,lH), 4.74(m,lH), 3.95(t,lH), 3.77 (t, 1H),3.6- 3.7 (m, 2H), 3.36 (m, 4H), 3.28 (t, 2H), 2.63 (t, 2H), 1.96 (m,2H). (S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo - J - oxazolidinyl] methyl] - 4
- oxo -4-(2- thienyl)butanamide.
!H NMR (CDC13, 8) : 8.08(d,lH), 7.77(dd,lH ), 7.3 - 7.7(m,7H ), 7.02(t,lH), 6.45 (t,lH),
4.81(m,lH), 4.00(t,lH),3.7- 4.0 (m, 2H), 3.57 (dt, 1H), 3.25 (m, 2H), 2.55 (m,2H).
(3? -N-[[3-(3-fluoro-4- morpholinylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4-
oxo - 4 -phenylbut - 2- enamide.
JH NMR (CDCI3, 8) :7.92 (d,lH), 7.84 (,d,lH), 7.2 - 7.6 (m, 6H), 6.98 - 7.1 (m, 3H), 4.38(m,
1H), 3.5 - 4.1 (m, 4H), 3.84 (m, 4H), 3.03 (m, 4H).
(S) -N-[[3-(3 -fluoro-4- piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4-(4
- methoxyphenyl) - 4- oxobutanamide.
'HNMR^MSOde, 8) : 8.25 (t, 1H), 7.79 (d, 2H), 7.38 (dd, 1H), 7.71 (dd, 1H), 6.95 (t,lH), 6.93
(d, 2H + 1H), 4.65 (m,lH), 3.75 (s,3H), 3.99 (t, 1H), 3.64 (dd, 1H), 3.06 (t, 2H), 2.81(m,4H), 1.3
-1.6(m.6H).
(S) -N-[[3-(3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4
- chlorophenyl) - 4- oxobutanamide.
lH NMR (CDCI3, 8) : 7.73(d,2H ), 7.33 (d,2H ), 7.2 - 7.8 (m, 2H),6.96(dd,lH), 6.34 (t,lH), 4.72(m,lH), 3.84(t,lH), 3.5- 3.8 (m, 3H), 3.21 (dd, 2H), 2.98 (m, 4H),2.54(t,2H), 1.5 - 1.7 (m,6H).
(S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl] -4-(2,4 - dimethylphenyl) - 4- oxobutanamide.
'H NMR (CDCI3, 8) : 7.55(d,2H ), 7.4 (m,lH ), 6.9 - 7.0 (m, 3H),6.32(t,lH), 4.70(m,lH), 3.90(t,lH), 3.74 (t,lH), 3.5- 3.7 (m, 2H), 3.20 (dd, 2H), 2.9 - 3.1 (m, 4H),2.52(t,2H), 2.34 ( s,3H), 2.71 (s, 3H ), 1.5 -1.9 (m,6H).
(S) - N-[[3 - (3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- methoxyphenyl) -4-oxobutanamide.
XH NMR ( CDCI3, 8) : 8.07(d, 1H), 7.2 - 7.8 (m,6H), 7.71(d,2H ), 6.79 (d,2H ), 6.51(t,lH), 4.81(m,lH), 3.4- 4.0 (m, 4H), 3.71 (s, 3H), 3.15 (qt, 2H), 2.52 (dd, 2H).
(S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- chlorophenyl) -4-oxobutanamide.
'H NMR (CDCI3, 8) : 8.09(d, 1H), 7.2 - 7.8 (m,6H), 7.75(d,2H ), 7.35 (d,2H ), 6.29(t,lH), 4.81(m,lH), 3.7 - 4.0(m, 3H), 3.5 - 3.7 (bt, 1H),3.25 (qt, 2H), 2.55 (t, 2H). (S)-N-[[3-(3-fluoro-4-(1,2,4-triazolyl)phenyl)-2-oxo-5- oxazolidinyljmethyl] -4- oxo — 4 - phenylbutanamide.
36

*H NMR (CDCI3, 8) : 8.62 (bs, 1H ), 8.10 ( s, 1H ), 7.7 -7.8 ( m, 2H ),, 7.67 (dd, 2H, ), 7.44 (t,
1H ), 7.2 - 7.4 (m,3H ), 6.49 (t, 1H ), 4.78 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55 (dt, 1H ), 3.30 (ddd,
2H), 2.54 (dd, 2H).
(S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4-(4- methylphenyl) -4- oxobutanamide.
XHNMR (CDC13, 8) : 8.71 (bs, 1H ), 8.10 ( s, 1H), 7.7 -7.9 ( m, 4H ), 7.30 (d, 1H, ), 7.21 (d, 2H
), 6.63 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.64(dt, 1H ), 3.35 (qdd, 2H), 2.5 - 2.6 (m, 2H),
2.35( s,3H).
(S) - N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -
4-(4- methoxyphenyl) -4- oxobutanamide.
'H NMR (CDCI3, 8) : 8.68 (bs, 1H ), 8.16 ( s, 1H ), 7.7 -7.9 ( m, 2H ), 7.79( d, 2H ) 7.28 (dd,
1H), 6.85 ( d,2H), 6.58 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.82(s,3H), 3.61(dt, 1H ), 3.32
(qdd, 2H), 2.65 (ddd, 2H).
(S) -N-][3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl]
-4-(2,4- dimethylphenyl) -4- oxobutanamide.
!HNMR (CDCI3,8) : 8.69 (bs, 1H ), 8.17 ( s, 1H ), 7.78( t,lH), 7.75 ( d,lH ), 7.60 (d,lH),7.25(d,
1H, ), 7.10 (d, 1H ),6.99(s, 1H ), 6.54( t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.65(dt, 1H ),
3.25 (qt, 2H), 2.59 (dt, 2H), 2.38( s,3H), 2.29 (s,3H).
(S) -N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4- oxo- 4 -(4 - thiomethylphenyl)butanamide.
'H NMR (CDCI3, 8) : 8.57 (bs, 1H ), 8.06 ( s, 1H ), 7.77 (m,2H), 7.61 (d, 2H), 7.19 ( d, 1H ),
7.10 (d, 2H, ), 6.47 (t, 1H ), 4.76 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25 (qdd, 2H), 2.55
(dq,2H),2.39(s,3H).
(S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide.
lU NMR (CDCI3, 8) : 8.58 (bs, 1H ), 8.06 ( s, 1H ), 7.80(t,lH),7.6 -7.8 ( m, 1H ), 7.67 (d,
2H,),7.32(d,2H), 7.26 (d, 1H ), 6.43 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25
(qt, 2H), 2.53(dt, 2H), 1.22( s,9H).
(S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo -5- oxazolidinyl] methyl]
-4-(2'- methyl - 4 - propylphenyl) -4- oxobutanamide.
'H NMR (CDCI3, 8) : 8.61 (bs, 1H ), 8.09 ( s, 1H ), 7.6 -7.8 ( m, 4H ), 7.24 (dd, 1H, ), 7.07 (d,
2H ), 6.38 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.54(dt, 1H ), 3.28(qt, 2H), 2.54(dt, 2H),
2.40( d,2H), 1.77 (pent.,lH), 0.81 (d,6H).
(S) - N-[[ 3-(3 -fluoro -4- (1,2,4 — triazolyl) phenyl) -2- oxo -5— oxazolidinyl] methyl]
-4-oxo - 4- (2- thienyl)butanamide.
37

'HNMR (CDCI3, 8) : 8.57 (bs, IH ), 8.05 ( s, IH ), 7.76 (t,lH),7.60(dd,lH), 7.53 (dd,lH), 7.25
(dd, IH, ), 7.01 (d, 2H ), 6.47( t, IH ), 4.78 ( m, IH), 3.7 - 4.0 (m, 3H), 3.56(ddd, IH ), 3.25 (qt,
2H), 2.54 (dt, 2H).
(S) -N-[[3 -(3 -fluoro -4- (1,2,4-triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl]-
4 - (2-naphthyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) : 8.41 (s, IH ), 8.27( s, IH ), 8.02(s,lH), 7.3 -7.9 ( m,6H ), 7.3 - 7.6 (m,
3H), 6.44 (t, IH ), 4.77 ( m, IH), 3.7 - 4.0 (m, 3H), 3.2- 3.7 (m, 3H), 2.5-2.6 (m, 2H).
(S) - N-[[3 - (3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4-(4- chlorophenyl) -4- oxobutanamide.
lH NMR (CDCI3, 8) : 8.58 (bs, IH ), 8.07 ( s, IH ), 7.6 -7.9 ( m, 2H ), 7.68 (d, 2H), 7.29 (d,
2H,), 7.2 - 7.3 (m, IH ), 6.31 (t, IH ), 4.81 ( m, IH), 3.7 - 4.1 (m, 3H), 3.55(dt, IH ), 3.25 (qt,
2H), 2.55(dt, 2H).
(S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4-
oxo -4-(2- thienyl)butanamide.
*H NMR (CDCI3, 8) : 7..5 - 7.7 ( m, 2H), 7.3 - 7.5 (m,lH), 6.8 - 7.3(m,3H ), 6.35(t,lH),
4.69(m,lH), 3.89 (t,lH), 3.76(t,lH),3.59(m,2H), 3.21(dd,2H),3.02 (m, 4H), 2.55 (t, 2H), 1.5 -
1.8 (m,6H).
(S) -N-[[3 -(3-fluoro -4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4-
(2'- methyl -4- propylphenyl) -4- oxobutanamide.
'H NMR (GDCI3,8) : 8.08 (m, IH ), 7.74 (d, 2H), 7.4 - 7.8 (m, IH ), 7.16 (d, 2H,), 6.97(dd,lH)
6.37 (t, IH ), 4.74 ( m, IH), 3.88 (t, IH), 3.80(t,lH), 3.4 - 3.71 (m, 2H), 3.40(m,4H) 3.25(dd, 2H
), 2.45(d, 2H), 1.80 (pent, IH), 1.5-1.8(m,6H),0.83(d,6H).
(S)-N-[[3-(3-fluoro-4-piperidylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(4
- acetamidophenyl) -4- oxobutanamide.
'H NMR (DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.78 (d, 2H), 7.60 ( d, 2H), 7.36 (dd, IH),
7.06 (dd, IH), 6.93 (t,lH), 4.63 (m, IH), 3.95(t,lH), 3.61 (dd,lH), 3.07(dd,lH), 2.81 (m,4H),
1.99 (s, 3H), 1.55 (m, 4H), 1.44 (m, 2H).
(S) - N-ff 3 -( 3 -fluoro - 4 * piperidylphenyl) - 2 - oxo - J - oxazolidinyl] methyl] -4-
oxo - 4 -phenylbut - 2- enamide.
JHNMR (CDCI3, 8) .-7.7-8.0 (m,3H), 7.2 - 7.6 (m, 5H), 7.01 (d,2H), 6.98 (t, IH), 4.80(m, IH),
4.01(t,lH), 3.85(t,lH), 3.77 (t, 2H), 3.16 (m, 4H), 1.5 - 1.9 (m,6H).
(S) - N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] ~4-
oxo- 4-(4- thiomethylphenyl)butanamide.
lU NMR (CDCI3, 8) :7.70 (d,2H), 7.60 (bd,lH), 7.0 - 7.3 (m, 3H), 6.91 (d,lH), 6.47 (t, IH),
4.71(m, IH), 3.87(t,lH), 3.4 - 3.8 (m,3H ), 3.45(m, 4H) 3.21 (dd, 2H), 2.54 (t, 2H), 2.45 (s,3H),
2.06(m,4H).
38

(S)-N-[[3-(3-fluoro-4-pyrrolidinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(2-naphthyl) -4- oxobutanamide.
!H NMR (CDC13, 8) : 8.35 (s, IH ), 7.5 - 8.1 (m, 8H ), 6.91(d,lH) 6.53 (t, IH ), 4.72 ( m, IH),
3.38 (m, 4H), 3.2 - 4.0 (m, 6H), 2.61(m, 2H), 1.99 (m,4H).
(S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] — 4 —
(2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide.
lU NMR (CDCI3, 8) :7.75 (d,2H), 7.46 (m,lH), 7.1 - 7.3 (m, 3H), 6.95 (d,lH), 6.44 (t, IH),
4.70(m, IH), 3.3 - 4.0 (m,4H ), 3.41(m, 4H) 3.24 (dd, 2H), 2.55 (t, 2H), 2.45 (d,2H),
2.01(m,4H), 1.81 (pent,lH), 0.83 (d, 6H).
(S) -N-][3-(3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-
(2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide.
lH NMR (CDCI3, 8) :7.76 (d,2H), 7.2 7.5(m, 4H), 6.95 (d,lH), 6.33 (t, IH), 4.69(m, IH),
3.88(t,lH), 3.71(t,lH), 3.6 - 3.7 (m,2H ), 3.45(m, 4H) 3.23 (dd, 2H), 2.56 (t, 2H), 1.94 (m,4H),
1.26(s,9H).
(S^J - N-[[3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4 —
(4 - acetamidophenyl) -4- oxobutanamide.
'H NMR (CDCU, 8) : 7.2 - 7.8 (m, 7H), 6.85 (d,lH), 6.47 (t, IH), 4.67(m, IH), 3.81(t,lH), 3.3 -
3.7 (m,3H ), 3.46(m, 4H) 3.16 (m, 2H), 2.3 - 2.9 (m,6H), 2.06(s,3H).
(Sp -N-[]3-(3-fluoro -4- pyrrolidinylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4-
oxo - 4 -phenylbut - 2- enamide.
'HNMR (CDCI3, 8) :7.8 - 7.9 (m,3H), 7.0 - 7.6 (m, 5H), 6.93 (d,lH), 6.75 (m,lH), 4.76(m, IH),
4.02(t,lH), 3.74 (m, 3H), 3.30 (m, 4H), 1.95 (m,4H).
(S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-
4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
!HNMR (CDCI3, 8) :7.78 (d,2H), 7.33 (dd,lH),6.99 (d,lH), 6.83 (t,lH), 6.81 (d, 1H),6.38 (t, IH)
4.69(m, IH), 3.86 (t,lH), 3.79 (s,3H), 3.5 - 3.8 (m,3H ), 3.41(m, 4H) 3.20 (m, 6H), 2.73(m,4H)
2.53 (t, 2H).
(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-
4 - (2,4 - dimethylphenyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) :7.55 (d,lH), 7.33 (dd,lH), 6.96 (m,3H), 6.81(t,lH), 6.22 (t, IH), 4.69(m,
IH), 3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.17(m, 6H) 2.73 (t, 2H), 2.45 (d,2H),2.51 (t,2H), 2.34(s,3H),
2.27 (s,3H).
(Si)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-
4 - oxo -4-(2- thienyl)butanamide.
!H NMR (CDCI3, 8) :7.63 (d,lH), 7.55 (d,lH), 7.33 (dd, IH), 7.05 (dd,2H), 6.85(t, IH), 6.31
(t,lH), 4.69(m, lH),3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.23(m, 6H) 2.73 (m, 4H), 2.55 (t, 2H).
39

(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - J - oxazolidinyl] methyl] -4-(4- acetamidophenyl) -4- oxobutanamide.
'HNMR ( DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.73(d, 2H), 7.59 (d, 2H), 7.38 ( dd, IH), 7.08(dd,lH), 6.99 (t, IH), 4.65 (m, IH), 3.95(t,lH),3.62(dd,lH), 3.08(m, 6H), 2.66 (m, 4H), 1.97 (s,3H).
(S) - N -[[ 3 - (3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] - 4 -oxo - 4 - (4 - thiomethylphenyl)butanamide.
•HNMR (CDC13,8) : 7.70 (d, 2H), 7.32 (dd,lH),7.14 (d, 2H,), 6.99(dd,lH), 6.82(t,lH), 6.33 (t, IH ), 4.68 ( m, IH), 3.86 (t, IH), 3.4 - 3.8 (m, 3H), 3.20(dt, 2H ), 2.90(t,4H) 2.53(t, 2H), 2.44(s,3H), 1.67 (m,4H), 1.5 (m,2H).
(S) -N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl] -4-(naphthyl) -4- oxobutanamide.
'H - NMR ( CDCI3) : 8.36 (s, IH ), 7.7 - 7.9 (m, 4H, ), 7.4 - 7.6 (m, 2H ), 7.32 (dd,lH), 6.99(d,lH), 6.78(t,lH), 6.43 (t, IH), 4.70 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.39(dt,2H), 2.86(t,4H), 2.61(t, 2H), 2.10(m,4H),1.50 (m,2H).
S) -N-[[ 3- (3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide.
lUNMR (CDCI3,8) : 7.75 (d, 2H), 7.37 (d,2H),7.31 (dd, IH, ), 7.00(dd,lH), 6.84(t,lH), 6.37 (t, IH ), 4.68 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.25(dt, 2H ), 2.91(t,4H) 2.54(t, 2H), 2.23(m,4H), 1.5 (m,2H), 1.26(s,9H).
(S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4-oxo -4-(4- thiomethylphenyl)butanamide.
'HNMR (CDCI3, 8) : 8.08 (d, 2H ), 7.77 (dd, IH, ), 7.63(d,2H), 7.2 - 7.5 (m, 4H ), 7.12 (d,2H), 6.41 (t, IH ), 4.81 ( m, IH), 3.98 (t, IH), 3.7 - 3.9 (m, 2H), 3.54(dt,lH), 3.22(qdd,2H), 2.54(dd, 2H), 2.36(s,3H).
(S) -N-[] 3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5 - oxazolidiny] methyl] -4-(2-naphthyl) -4- oxobutanamide.
'HNMR (CDCI3, 8) : 8.35( s,lH), 8.08 (d, IH ), 7.6 - 7.8(tn,5H), 7.2 - 7.6 (m, 7H ), 6.41 (t, IH ), 4.82 ( m, IH), 3.8 - 4.0 (m, 3H), 3.3 - 3.7(m,3H), 2.64(dd, 2H).
(S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4 - (2',2' - dimethyl- 4 - ethylphenyl) -4- oxobutanamide.
*H NMR (CDCI3, 8) : 8.08 (d, IH ), 7.80 (dd, IH, ), 7.70(d,2H), 7.57(t, IH), 7.2 - 7.5 (m, 4H ), 7.08 (d,2H), 6.41 ( t, IH ), 4.80 ( m, IH), 3.7 - 4.0 (m, 3H), 3.55(dt,lH), 3.1 - 3.4(m,2H), 2.54(dd, 2H), 2.37(d,2H), 1.72(pent,lH), 0.76(d,6H).
40

(S)-N-[[3-(3-Jluoro-4- henzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide.
JHNMR(CDC13, 5) :7.2 - 8.0 (m,13H), 6.95 (d,lH), 6.65 (m,lH), 4.89(m, IH), 4.18(t,lH), 3.7-4.0 (m, 3H).
(S) -N-[[3-(3-Jluoro-4-benztriazolylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 -(4- acetamidophenyl) -4- oxobutanamide.
!HNMR (DMSOde, 8) : 10.16 (s, IH), 8.29(t, IH), 8.12 (d, IH), 7.79 (m, 4H), 7.58 ( d, 2H), 7.4 - 7.5 (m, 4H), 4.74 (m, IH), 4.13(t,lH),3.08(dd,lH), 3.10 (t, 2H), 1.97 (s, 3H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide.
lH NMR (CDCI3,8) : 7.76 (d, 2H), 7.53 (dd, 1H),7.39 (d, 2H +1H, ), 7.02(d,lH), 6.29 (t, IH ), 4.71 ( m, IH), 3.89 (t, IH), 3.79(t,lH), 3.5 - 3.7 (m, 2H), 3.38(m, 4H ), 3.24 (dd,2H), 2.92(m,4H) 2.54(t, 2H), 1.26(s,9H).
(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide.
JH NMR (CDCU, 8) :7.8 - 7.9 (m,3H), 7.3 - 7.7 (m, 5H), 6.8 -7.0 (m,3H), 4.81(m, IH), 4.05(m,lH), 3.75 (m, 3H), 3.49 (m, 4H), 3.10 (m,4H).
(S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(fi- naphthyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) : 8.35 (s, IH), 7.7-8.0 (m, 4H), 7.3-7.7 (m, 5H), 7.01 (m, IH), 6.48 (m, IH), 4.74 (m, IH), 3.80 (m, 3H), 3.60 (m, IH), 3.37 (m, 6H), 2.93 (m, 4H), 2.60 (m, 2H) (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4- (4- chlorophenyl) -4-oxobutanamide.
!H NMR (CDCI3, 8) : 7.74 (d, 2H), 7.54 (d, IH), 7.34 (d, 2H+1H), 6.98 (d, IH), 6.35 (t, IH), 4.78 (m, IH), 3.88 (t, IH), 3.5-3.8 (m, 3H), 3.38 (m, 4H), 3.22 (dd, 2H), 2.93 (m, 4H), 2.54 (t, 2H).
(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4 - (2,4 - dimethyl- 4 ethylphenyl) -4- oxobutanamide.
lH NMR (CDCI3, 8) : 7.95 (m, IH), 7.74 (d, 2H+1H), 7.77 (d, 2H), 7.07 (d, IH), 6.38 (t, IH), 4.76 (m, IH), 3.91 (t,lH), 3.4-3.8 (m, 3H), 3.58 (m,4H), 3.25 (dd, 2H), 3.1 (m, 4H), 2.54 (t, 2H), 2.46 (d, 2H), 1.80 (pent, IH), 0.85 (s, 3H), 0.82 (s, 3H). Microbiology: Pharmacological testing
The compound of formula (I) of the present invention displayed antimycobacterial activity when tested by in vitro growth inhibition assay and agar incorporation methods. The minimum inhibitory concentrations (jag/ml) obtained for representative compounds of formula (I)
41

against M. tuberculosis including sensitive and resistant strains are summarized in Table-I. The MIC value of a representative preferred Compound No. 30 of formula I against different species of mycobacteria is summarized in Table-II. in vitro Growth Inhibition assay
The ability of the compounds 1-78 of formula (I) of this invention to inhibit the growth of Mycobacterium species was determined by the BACTEC 460 TB system. The reference strain M tuberculosis H37Rv ATCC 27294 was grown in Middlebrook 7H9 broth containing 10% ADC
supplement at 37°C on a rotay shaker at 150 rpm for grown for 7days. The turbidity of the culture was adjusted to 1.0 Mc farland. The BACTEC 7H12B medium vials were seeded with 0.1ml of the 1.0 Mc farland adjusted M. tuberculosis culture. In the control vials 0.1ml of the culture was added after lOOfold dilution of the initial inoculum. Stock solution of lmg/ml of each compound was prepared in DMSO in separate sterile tubes. The compounds were further diluted to concentration of 25 ^g/100 ul, 0.1ml was than added to the 7H12B vial containing mycobacterial culture so that final concentration of the compound 6.25 u.g/ml. The cap in all the vials were cleaned with isopropanyl alcohol and kept in racks. The vials were then incubated at 37°C without shaking. Test vials was read daily on the BACTEC system till the GI of the control vial reached > 30.Once the GI in the control reached 30 AGI (GI = GI (n> - GI („.i) ) was determined for all test and control vials. If AGI of test vial is less than that of the control vial the culture was sensitive to the test compound. in vitro Agar Dilution assay
MIC of compound of formula (I) of this invention against strains of Mycobacterium were determined by a reference agar dilution method as per the NCCLS- M24-T2. recommendations. The compounds were dissolved in DMSO and diluted twofold to obtain ten serial dilutions of each compound. Appropriate volume of compounds were incorporated into duplicate plates of Middlebrook7H10 agar medium supplemented with 10% Middlebrook supplement oleic acid-albumin-dextrose (OADC) enrichment at concentration of 0.03u,g/ml to 16|j,g/ml. Test organisms (mycobacterium strains) were grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement. After 7 days of incubation at 37°C the broths were adjusted to the turbidity of 1.0 McFarland standard; the organism were further diluted 10 fold in sterile water containing 0.10% Tween-80. The resulting mycobacterial suspensions were spotted (3-5jxl/spot) onto drug supplemented 7H10 media plates. The plates were sealed and incubated at 37°Cfor 3-4 weeks in upright position. The MIC was recorded as the lowest dilution of the drug that completely inhibited the growth of test organisms. Test isolates included 10 clinical isolates that were generally susceptible to common tubercular agents and 10 strains that were resistant to one or more standard anti tubercular drugs. Appropriate reference strains and control drug was included in each batch of test.
42

in vivo studies:
The efficacy of the compound of formula (I) of this invention was also evaluated in murine model of pulmonary tuberculosis. Mycobacterium tuberculosis cultures grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement at 37°C for 7 days on a rotary shaker. For, animal inoculation liquid cultures were declumped by brief sonication and were diluted appropriately in 7H9 broth to obtain a concentration of lxl07CFU's/ 0.2ml. Four-week-old male outbred Swiss albino mice housed in a pathogen free, biosafety level 3 environment within micro isolator cages were used throughout the study. Infections were produced by intravenous inoculation into caudal tail vein of 0.2ml of declumped M. tuberculosis suspension. Following infection, mice were randomly distributed in different groups of six each.
Treatment for initial study was started one day after infection. For, treatment Compound No. 30 of formula I was dissolved in 10% PEG. Isoniazid was dissolved in sterile water. The drugs were prepared each morning prior to administration. Therapy was given 5 days per week for four weeks. All the agents were administered by gavage and were dosed at 50,25,12.5mg / kg of body weight. Control group of infected but untreated mice were killed at the initiation of therapy (early control) or at the end of the treatment period (late control). Mice were sacrificed by cervical dislocation 3-5 days after the administration of the last dose of drug. The spleens and right lung were removed aseptically and homogenized in tissue homogeniser. At least 4 serial tenfold dilution of the homogenate was plated onto selective Middlebrook 7H11 agar plates in duplicate. The colony counts were recorded after incubation at 37°C for 4 weeks. The viable cell counts were converted to Logio values. A compound showing 2 Log reduction in viable counts compared to the controls was considered significant.
The in vivo data for a representative compound of formula (I) is given in Table-II.
Acute toxicity of Compound No. 30 of Chart-I was estimated in mice and the LDo was found to be >1000 mg/kg P. O.
43

Table-I: in vitro activity of compounds 1 to 58 of formula (I),

Compound No. Growth inhibition of
M.tuberculosis
27294 MIC (fig/ml) against

M.tuberculosis 27294 Clinical isolates

Sensitive Resistant
1 + 16 4-16 >16
2 + 8 8 8
8 + 2 .5-2 2-4
13 + 2 2 2-4
14 + 0.25 0.25-0.5 4->16
15 + >16 >16 >16
16 + 0.5 0.5 0.5(>16)
17 + 0.5 1.0 0.5-1.0
18 + 4- 1-4 8->16
19 + 2 1-2 2
20 + 1 1-2 2-4
21 + 0.5 0.5-2 0.5(>16)
25 + 4 4-16 4->16
27 + >16 >16 >16
28 + 0.5 1-2 2-8
30 + 0.5 0.5 0.5-2
31 + 1 1-2 1-4
32 + 0.25 0.25-0.5 4-(>16)
33 + 0.5 1 0.5-2
34 + >16 >16 >16
35 + 4 2-4 4-8
36 + 4 4-8 4-8
44

Table-I Contd....

39 + 2 2-4 2-8
40 + 1 1-2 1-2
43 + 1 0.5-1.0 1-2
44 + 1 0.5-2 1-4
45 . + 2.0 2-4 2-4
46 + 2 2-4 2-8
47 + 1 1-2 2-4
48 + 2 2-4 2-8
49 + 4 4-16 4-16
50 + 2 2-4 2-4
51 + 8 8->16 8->16
52 + 2 2 4->16
53 + >16 >16 >16
54 + 8 8-16 >16
55 + >16 >16 >16
56 + >16 >16 >16
57 + 16 16->16 >16
58 + 8 8-> 16 8-> 16
Isoniazid + 0.25 0.12- .25 8 - >16
Linezolid + 0.5 0.25-0.5 1.0-2.0
Table-II MIC values of compound of formula (I) against different species ofMycobacteria

Sr.
No. Compound No. MIC (ug/ml)

M. tuberculosis M.avium-
intracellular
complex M.fortuitum M.kansai

Sensitive Resistant

1 Compound 30 of formula I 0.50 0.50-2.0 8.0->16.0 >16.0 8.0
2 Isoniazid 0.25 4.0-> 16.0 8.0->16.0 >16.0 >16.0
45

Table-m in vivo activity of Compound of formula (I) against M. tuberculosis ATCC 27294" infection
in Swiss albino mice

Sr. No. Drug& Dose b (mg/kgday" ') or group Mean Logio No. of CFU Mean Logio No. of reductionc

Lung Spleen Lung Spleen
1 Compound 30 of Chart-I
50mg/kg 25mg/kg 12.5mg/kg 2.12 2.21 4.34 2.09 2.13 4.30 2.40 2.30 0.20 2.53 2.49 0.26
2 Isoniazid
50mg/kg 25mg/kg 12.5mg/kg 2.03 2.11 2.95 1.92 2.11 2.94 2.49 2.41 1.57 2.70 2.51 1.68
3 Infected early control 4.52 4.62
4 Infected late control 6.57 6.37
a- inoculation of logio:- 7.00 Mycobacteria.
b- mice were dosed 5 day/week for 4 weeks. From day 1 -28.
c- difference in mean logio number CFU from that of early controls.
The compound of formula I of this invention may be administrated to a subject such as a human being or an animal in need of such an administration through any route appropriate to the condition to be treatede. Suitable routes of administration include oral, rectal, nasal, topical (both buccal and sublingual), vaginal and parenteral (including subcutaneous, intramuscular, intradermal, intrathecal and epidural).
Pharmaceutical compositions of compound of formula I can be prepared in adjunction with inert pharmaceutically acceptable carriers, which can either be solid or liquid.
Solid form preparations include powders, tablets, dispersible granules, capsules, cachets, suppositories and ointments. The solid carriers can be one or more substances which may act also as diluents, flavouring agents, solubilisers, lubricants, suspending agents, binders or tablet disintegrating agents. It can also be finely divided solid which is in admixture with finely divided active compound. Suitable solid carriers are lactose, pectin, dicalcium phosphate, microcrystalline cellulose, sucrose, kaolin, dextrin, gelatin, starch, tragacanth, low melting wax, coca butter and the like.
Liquid preparations include solutions, suspensions and emulsions, e.g. solutions of compound of formula I in water or water-propylene glycol mixture for parenteral injection. Liquid preparations can also be formulated along with non-ionic surfactants and edible oils such as corn, peanut and sesame oils. Aqueous solutions for oral use can be prepared by dissolving the active component in water and adding suitable colorants, flavours stabilizing and thickening
46

agents, as required. Aqueous suspension for oral use can be made by dispersing the finely divided active component in water with a viscous material, e.g. natural or synthetic gums, resins, methyl cellulose, sodium carboxymethyl cellulose and othe known suspending agents. The adjuvants may also include preserving agents and anti-oxidants.
Compositions for topical application may take the form of liquids or gels, containing a therapeutically effective concentration of compound of formula I admixed with a dermatologically acceptable carrier.
The pharmaceutical preparations may be in unit dosage form. In such form, the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage can be in the form of tablets, capsules, powdersin vials or ampoules, ointments, gels, creams or any other form. The quantity or concentration of the active compound in such unit dose preparations may be varied or adjusted according to the particular application and potency of the active ingredient.
47

A compound of formula (I) and its pharmaceutical^ acceptable salts

wherein,
A is either hydrogen or fluorine,
B is either hydrogen or fluorine,
A and B together is hydrogen and fluorine,
Ri is a group of formula,

wherein,
Q is either an alkyl group of two carbon atoms, an alkene group of two carbon atoms or
an alkyne group of two carbon atoms
Y is oxygen, sulfur or an amino function of formula NR3
wherein,
R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be
straight or branched; cycloalkyl of 3-7 carbon atoms; CHO, -COOH, -COOR,; COCR,;
CN; aryl or heteroaryl
wherein,
Rt is an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of
3-6 carbon atoms.
Ar is a substituted phenyl ring or a substituted pyridine ring of formula

—O-R3
or Ar is a five membered ring of formula
48

or Ar is a fused bicyclic phenyl or pyridine ring of formula

wherein,
M is either CH or N
Z is CH, NH, O, or S,
X is a group selected from OR,, NR4R5, N02, SR,, SOOR,, SOONR4R5, F, CI, Br or I,
wherein R4 is as defined hereinbefore, and
and R3 is as defined hereinbefore
R5 is hydrogen or R4
R2 is selected from the groups shown below, and the corresponding N-oxides thereof.

A compound according to Claim 1 wherein in said compound of formula I Aryl is phenyl substituted with (0) or (1) of F, CI, "OCH3, "OH, "NH2, CrC4 alkyl, 0-C(0)-OCH3," N02or"CN.
49

3. A compound according to Claim 1 wherein said compound of formula I is selected from the group consisting of:
1) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl
] methyl ] - 4 - oxo - 4 - phenylbutanamide.
2) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
3) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
4) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide.
5) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
6) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
7) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide.
8) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
9) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
10) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
11) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide.
12) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide.
13)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
14) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide.
15) (S) - N -[ [ 3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide.
16) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl 1 methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide.
17) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
50

18) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
19) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl]-4-oxo-4-(2-thienyl)butanamide.
20) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
21)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide.
22) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
23) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
24) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
25) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
26) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) — 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
27) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
28) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide.
29) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide.
30) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide.
31)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (2 - thienyl)butanamide - N - oxide.
32) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide.
33) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N -oxide.
34) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
51

35) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4- oxobutanamide.
36) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4- oxobutanamide.
37) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4- oxobutanamide.
38) (S) - N -[ [ 3 - (3 - fluoro - 4 - benztriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
39) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
40) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
41) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4 - oxobutanamide.
42) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
43) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
44) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide.
45) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
46) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
47) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide.
48) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide.
49) (S) - N .-[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
50) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
51) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
52) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide.
52

53) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
54) (S) -N-[[3-(3- fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
55) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
56) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -■ ( 4 - thiomethylphenyl )butanamide.
57) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2 - naplrthyl) - 4 - oxobutanamide.
58) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide.
59) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
60) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
61)(S)-N-[[3-(3- fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
62) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
63) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
64) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide.
65) (S) - N -[ [ 3 - ( 5 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
66) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (4 - thiomethylphenyl)butanamide.
67) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
68) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
69) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide.
70) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
53

71) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
72) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
73) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
74) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
75) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
76) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) --2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2 - naphthyl) - 4 - oxobutanamide.
77) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - '2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
78) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -
oxazolidinyl ] methyl ] - 4 - (2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide.
- '
4. A compound as claimed in claim 3 wherein said compound of formula I is selected from the group of N-oxide of the said compounds 1 to 78.
5. A pharmaceutical composition comprising a) atleast one of I) any compound of claims 1 to 4 and II) its pharmaceutically acceptable salts and b) a pharmaceutically acceptable carrier.
6. A pharmaceutical composition according to claim 5 comprising a solid or liquid preparation.
7. A pharmaceutical composition as claimed in anyone of claims 5 to 6 for oral or parenteral administration.
8. A method of preparation of the compound of formula I and/or its pharmaceutically acceptable salts comprising:
coupling of the amino fragment of compound of formula II
5^

(II)

with a carboxylic acid of formula III in the presence of an acid activating group or a dehydrating agent in a suitable solvent.

(Ill)

wherein R2 has the same meaning as given in claim 1.
9. A method as claimed in claim 8 wherein the compound of formula II is preferably selected
from (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 -
oxazolidinyl] methyl amine, (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 -
oxo - 5 - oxazolidinyl] methyl amine,(S) - N -[3 - ( 3 - fluoro - 4 -
benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3
- (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, S) - N -[3 - (3 - fluoro - A - benzotriazolylphenyl) - 2 - oxo - 5 -oxazolidinyl] methyl amine, and (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine.
10. A method as claimed in anyone of claims 8 or 9 wherein the compound of formula III is
selected from 4-(2-Naphthyl)-4-oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic acid, 4-oxo-4-(2' methy lpropyl)phenylbutanoic acid, 4-Oxo-4-(2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 -
5S

oxobutanoic acid,4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 -
methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid,
. 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -difluorophenyl) - 4 -
oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 -
oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 -
phenyl - but - 2 - ynoic acid.
11. A compound of formula I, its pharmaceutically acceptable salts and pharmaceutical compositions obtained thereof substantially as herein described and illustrated.
Dated this 5th day of March 2005
Dr. Sanchita Ganguli
Of S. MAJUMDAR & CO.
Applicants' Agent
5t
F0RM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. - OXAZOLIDINONE DERIVATIVES, PROCESS FOR THEIR
PREPARATION AND THEIR USE AS ANTIMYCOBACTERIAL AGENTS
2. Applicants)
(a) NAME : LUPIN LIMITED
(b) NATIONALITY : An Indian Company
(c) ADDRESS : 159, C.S.T. Road, Kalina, Santacruz (East),
Mumbai - 400 098, Maharashtra, India
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed

FIELD OF THE INVENTION
The present invention relates to novel compounds belonging to the class of oxazolidinones useful in the treatment of acid fast organisms such as Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium spp. The present invention further relates to methods for preparation of the novel compounds and to pharmaceutical compositions containing the novel compounds useful in the treatment of tuberculosis. BACKGROUND OF THE INVENTION
Tuberculosis (TB), an infectious disease caused by the bacterium Mycobacterium tuberculosis is transmitted mainly through air, affecting most often the lungs. When persons with pulmonary TB cough they produce tiny droplet nuclei containing M. tuberculosis, which remain suspended in air for a prolonged period of time. A person who breathes the air containing the aforesaid droplet nuclei containing M. tuberculosis can become infected with TB.
TB, one of the three major infectious diseases in the priority list of the World Health Organization's (WHO) agenda kills about two million people around the world every year. About six million new cases are reported every year and nearly 20% of adult deaths and 6% of infant deaths are attributable to the disease (C. Dye et. al., J. Am. Med. Ass., 1999, 282, 677-686). About a billion people are expected to be affected by TB by the year 2020, with 35 million likely to succumb to the disease (WHO Fact Sheet No. 104, Global Alliance for TB Drug Development- Executive Summary of the Scientific Blueprint for TB Development : http://www.who.int/inf-fs/en/factl04.html).
With the emergence of the AIDS epidemic and the increase in cases of HIV coupled with TB as well as the continued resistance of M. tuberculosis to isoniazid and rifampicin, the two most powerful anti-tubercular drugs available today there is an urgent need for new anti-tubercular drugs to combat the killer disease (S. H. E. Kaufmann et. al., Trends Microbiol., 1993, 1,2-5 ; B. R. Bloom et. al., N. Engl. J. Med., 1998, 338, 677-678).
Although, many new compounds are becoming available for fighting a number of infectious diseases, the number of such compounds having antimycobacterial activity are few. This could partly be due to the complexity of research involved and partly due to business considerations (B. N. Roy et. al., J. Ind. Chem. Soc, April 2002, 79, 320-335 and references cited therein).
However, renewed thrust in research in the last decade has resulted in development of new antimycobacterial compounds,
a) differing widely in structures,
b) having different mode/mechanism of action,
c) possessing favourable pharmacokinetic properties,
d) which are safe and have low incidence of side-effects, and
e) which provide a cost-effective dosage regimen.
2

Among the aforesaid new compounds, the oxazolidinones first developed during the mid-1980s (W. A. Gregory et. al., J. Med. Chem., 1989, 32,1673-1681 and 1990,33,2569-2578 ; C-H Park et. al., J. Med. Chem., 1992, 35, 1156-1165) are a unique class in themselves. The in vivo results for some of the oxazolidinones show that they are active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, including resistant strains such as methicillin-resistant Staphylococcus aureus [MRSA], methicillin-resistant Streptococcus epidermidis [MRSE], penicillin-resistant Streptococcus pneumoniae [PRSP], vancomycin-resistant enterococci [VRE], etc. (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999,9 (5), 625-633 and the references contained therein).
The oxazolidinones inhibit bacterial protein synthesis at a very early step in the initiation of complex formation involved in the process of translating mRNA into protein. The oxazolidinones, in general, are not cross-resistant with any known antibiotic because of this unique mechanism (D. C. Eustice et. al., Antimicrob. Agents Chemother., 1988, 32, 1218 and Biochem. Biophys. Res. Commun., 1988,150. 965).
A feature of the oxazolidinone molecule is that only those compounds, which are enantiomers with a (5S)-acetamidomethyl configuration in the left side of the molecule are known to exhibit antibacterial activity (W. A. Gregory et. al., J. Med. Chem., 1989, 32, 1673-1681). Another feature is that most of such antibacterial compounds invariably carry a (substituted) phenyl ring attached to the nitrogen atom of the oxazolidinone ring in the right side of the molecule (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999, 9 (5), 625-633 and the references contained therein).
The most promising compound among the N-phenyl oxazolidinones, which has been approved for human use is (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidin-yl]methyl]-acetamide), commonly known as linezolid (M. Barbachyn et. al., WO 995/07271). Linezolid possesses good in vitro and in vivo potency against most of the Gram-positive bacteria, including resistant strains {Drugs of the Future, 1996,21.(11), 1116-1123).
The left hand side i. e. position 5- and the right hand side i. e. position 3- respectively of
the oxazolidinone ring nucleus allows for many variations and has resulted in the discovery of a
large number of compounds having antimicrobial and antibacterial properties. Such
representative compounds, albeit not meant to be limiting are disclosed in the following prior art
references. These are:
i) US 4,942,183 (Gregory et. al.) and US 4,948,801 (Carlson et. al.) collectively disclose
certain 3-substituted phenyl- 5-aminomethyl oxazolidinones, possessing useful
antibacterial activity, ii) US 5,529,998 (Habich et. al.) discloses certain 3-benzoxazoyl- and benzothiazolyl-5-
acetyl amino methyl oxazolidinones, useful as antibacterial medicaments.
3

iii) US 5,565,571, US 5,654,428, US 5,756,732, US 5,801,246 and US 5,929,248 (Barbachyn et. al.) collectively disclose several substituted aryl and heteroaryl phenyloxazolidinones carrying an acetyl aminomethyl function at the 5-position, specifically oxazolidinones having an aryl or heteroaryl group at the para position of the 3-phenyl ring and additional substituents at the meta positions of the 3-phenyl ring, which are useful as antibacterials.
iv) US 5,652,238 (Brickner et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a hydroxyl acetyl piperazine moiety, active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, as well as anerobic organisms such as bacteroides and Clostridia species as well as acid-fast organisms such as Mycobacterium tuberculosis.
v) US 5,684,023 (Riedl et. al.) discloses certain 3- benzofuranyl- and benzothienyl oxazolidinones, carrying an azido, hydroxy or acetyl aminomethyl group at the 5-position, useful as antibacterial medicaments.
vi) US 5,688,792 (Barbachyn et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a (substituted)-morpholine. Such compounds are useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp.
vii) US 5,719,154 (Tucker et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the said substitution being a pyrimidinyl or pyradazinyl group. Such compounds are useful as antimicrobial agents.
viii) US 5,736,545 (Gadwood et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a five membered heterocycle ring, in particular an azolyl ring. Such compounds are useful in the treatment of microbial infections.
ix) US 5,792,765 (Riedl. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-substituted phenyloxazolidinones, the substitution being a heterocyclic moiety, useful as antibacterial medicaments.
x) US 5,861,413 (Habich et. al.) discloses certain 2-oxo and 2-thio-l,2-dihydroxyqoinolinyl-1-oxazolidinones, useful as antibacterial medicaments.
xi) US 5,880,118 (Barbachyn et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a
4

substituted thiomorholine moiety i. e. oxazine and thiazine derivatives, useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp.
xii) US 5,910,504 and US 6,124,334 (Hutchinson et. al.) collectively disclose certain substituted 5-acetyl aminomethyl-3- phenyloxazolidinones substituted at the para position of the 3-phenyl ring with a heteroaromatic moiety, which is five membered having one to four nitrogen atoms or alternatively, a benzoannulated five-membered heteroaromatic ring having one to four nitrogen atoms, useful as antibacterials.
xiii) US 6,069,160 (Stolle et. al.) discloses certain substituted 5-acetyl aminomethyl-3-benzocyclopentaneoxazolidinones, containing an heteroatom, useful as antibacterial medicaments.
xiv) US 6,227,868 Bl and US 6,410,728 (Sciotti et. al.) collectively disclose certain 5-acetyl aminomethyl-3-phenyloxazolidinones carrying an acetylenic moiety on the 3-phenyl ring, useful for treating bacterial infections, psoriasis, arthritis and toxicity due to chemotherapy.
xv) WO 93/23384 (Hutchinson et. al.) discloses certain substituted 5-acetyl aminomethyl-3 -phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, useful for treatment of microbial infections caused by staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium.
xvi) WO 97/10223 (Gadwood et. al.) discloses certain substituted 5-acetyl aminomethyl-3-aminoaryl oxazolidinone N-oxide compounds, which are exceedingly water soluble and useful in preparation of pharmaceutical compositions for combating a number of human and veterinary pathogens, staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium, Mycobacterium spp. and Mycoplasma spp.
xvii) WO 98/01446 and WO 98/01447 (Betts et. al.) collectively disclose certain substituted 5-acetyl aminomethyl3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a six-membered heteroaryl ring containing two or three ring nitrogen atoms as the only ring heteroatoms, useful as antibacterial agents.
xviii) WO 99/02525 (Thomasco et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted by a thiadiazolyl or oxadiazolyl moiety, useful as
5

antimicrobial agents, effective against a number of human and veterinary pathogens, including Gram-positive and Gram-negative aerobic bacteria.
xix) WO 99/37630 (Gordeev et. al.) discloses oxazolidinone combinatorial libraries, compositionscontaining the same and methods of preparation thereof involving solid phase synthesis, which provides the said compounds for high-throughput screening.
xx) W099/37641 (Bartel. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-bicyclene-substituted oxazolidinones, useful as antibacterial medicaments.
xxi) WO 01/09107 (Gordeev et. al.) discloses certain 3-heteroaryl-5-acetyl aminomethyl oxazolidinones, substituted by a thioacyl, aminocarbonyl, alkoxycarbonyl, aminothiocarbonyl, alkoxythiocarbonyl and alkylthiocarbonyl group, useful in treating or preventing an infectious disorder in humans or animals.
xxii) WO 01/42242 (Paget et. al.) discloses certain substituted 5-acetyl aminomethyl 3-substituted phenyloxazolidinones, the substitution being a bicyclic heterocyclic system, useful as antibacterial agents.
xxiii) WO 02/06278 (Mehta et. al) discloses certain substituted 3-phenyl oxazolidinones and to process for synthesis of the same, the said compounds useful as antibacterial agents, effective against a large number of human and veterinary pathogens, including Gram-positive bacteria and acid fast organisms such as Mycobacterium tuberculosis.
xxiv) WO 02/20515 (Madar et. al.) discloses heterocyclic phenyloxazolidinones, useful for treating bacterial infections. However, only a few of the disclosures described hereinbefore provide compounds that
can be used as antimycobacterials, while most of the others are silent about the antimycobacterial
activity of the disclosed compounds.
A need, therefore, exists for new compounds possessing potent antimycobacterial
properties for treatment of TB, which as mentioned hereinearlier is assuming alarming
proportions.
OBJECTS OF THE INVENTION
It is thus the basic object of the present invention to synthesize, identify and provide new
compounds belonging to the class of oxazolidinones, possessing potent antimycobacterial
properties especially for treatment of acid fast organisms such as Mycobacterium tuberculosis,
Mycobacterium avium-intracellular complex, M. fortuitum and M. kansai.
Another object is directed to providing antimycobacterial pharmaceutical composition
effective in inhibiting/treating the generation of mycobacterial conditions/cells including
Mycotacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M fortuitum and Mkansai.
6

Yet another object is directed to providing a method of treating/inhibiting mycobacterial cells/conditions involving the administrations of effective amount of the novel antimycobacterial compound and/or its salts /composition of the invention. SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention there is provided compound of formula (I) and its pharmaceutically acceptable salts thereof

wherein,
A, B = H, and/or F Ri is a group of formula

wherein,
Q is CH2-CH2, CH=CH, or C=C
Y is O,S or NR3
wherein,
R3 is Ci - C4 alkyl (straight, branched, unsaturated), cycloalkyl, COOH, COOR,, CHO, COCR4,
CN, aryl, heteroaryl
wherein,

R is an alkane of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon
atoms, and
Ar is an aromatic carbocycle represented by

7

wherein,
X is OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, Br, CI, F, or I,
M is-CHorN,and
Zis-CH,-NH,OorS
and wherein,
R3 and R4 are as described hereinbefore, and
R5 is H, or same as R4, and
R.2 is selected from the groups shown below, and the corressponding N-oxides thereof

Heteroaryl or Heterocycloalkyl wherein K is O, S, SO, S02, or CH2
According to another aspect of the invention there is provided a pharmaceutical
composition comprising:
i) atleast one of an antimycobacterially effective amounts of compound of formula I and
pharmaceutically acceptable salts there of; and ii) a pharmaceutically acceptable carrier.
According to yet another aspect of the present invention there is provided a method of inhibiting growth of mycobacterial cells such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M.kansai.,comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof.
8

According to yet another aspect of the present invention there is provided a method of treating mycobacterial conditions such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M kansai, comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof.
According to another aspect, there is provided a process for the manufacture of the compound of formula I or its pharmaceutically acceptable salts comprising : coupling the amino fragments of compound of formula II with the carboxylic acid fragment of formula III.
The above disclosed compound of formula I its pharmaceutically acceptable salts thereof are found to have antimycobacterial properties and the same in admixture with pharmaceutically active additives, an be administrated orally or paranterally for treatement of mycobacterial conditions especially TB. DETAILED DESCRIPTION OF THE INVENTION
In the pharmaceutically active compound of formula (I) of this invention,

the definition of the symbols and groups A, B, Rt and R2 are as follows :
A is either hydrogen or fluorine,
B is either hydrogen or fluorine,
A and B together is hydrogen and fluorine,
When A is hydrogen, B is fluorine and vice-versa.
R1 represents a group of formula,

Q is either an alkyl group of two carbon atoms (CH2-CH2), an alkene group of two to carbon atoms (CH=CH), or an alkyne group of two carbon atoms (C=C)
9

Y can either be oxygen, sulfur or an amino function of formula NR3, wherein
R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or
branched. Suitable alkyl groups are methyl, ethyl, n-propyl, n-butyl, iso-propyl, iso-butyl, tert-
butyl, ethylene, propylene, 1, butene, both the geometric isomers of 2-butene i. e.(cis)-2-butene
and (trans)-2-butene, and iso-butylene. or
R3 is a cycloalkyl group of 3-7 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl,
cyclohexyl and cycloheptyl, or
R3 is a carboxylic acid group (-COOH) or a carboxylic acid ester of formula-COOR4, wherein
R4 is H, an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6
carbon atoms.
R3 is further an aldehyde (-CHO), an acetyl group (-COCR4), wherein R4 is as mentioned
hereinbefore or R3 is a nitrile (CN), aryl or heteroaryl, wherein
Aryl is phenyl substituted with (0) or (1) of-F, -CI, -OCH3, -OH, -NH2, -CrC4 alkyl, -O-C(O)-
OCH3,-N02or-CN,and
Heteroaryl
or Ar is a five membered ring of formula
or Ar is a fused bicyclic phenyl or pyridine ring of formula
10
The group Ar is a substituted phenyl ring or a substituted pyridine ring of formula

wherein,
M is either CH or N; Z is -CH, -NH, O or S and R3 is as defined hereinbefore,
X is a group selected from OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, F, CI, Br or I, wherein
R4 is as defined hereinbefore, and
R5 is hydrogen or R4.
R2 is selected from the groups shown below, and the corresponding N-oxides thereof.

Heteroaryl or Heterocycloalkyl
wherein K is O, S, SO, S02, or CH2
The preferred novel compounds of formula (I) that form part of this invention, are as follows.
The following compounds 1 to 78( named as per IUPAC or CAS nomenclature) are preferred compounds of formula (I) of the invention.
1. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide.
2. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
3. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
4. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide.
5. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
11

6. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide.
7. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide.
8. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
9. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
10. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ]
- 4 - oxo - 4 - phenylbutanamide.
11. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methylphenyl) - 4- oxobutanamide.
12. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - (4 - methylphenyl) - 4- oxobutanamide.
13. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
14. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide.
15. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide.
16. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide.
17. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
18. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
19. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide.
20. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - (2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
21. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide.
22. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
23. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
12

24. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazohdinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
25. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazohdinyl methyl] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
26. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazohdinyl ] methyl
- 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide.
27. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
28. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl
- 4 - oxo - 4 -( 2 - thienyl)butanamide.
29. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide.
30. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide.
31. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide.
32. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide.
33. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N - oxide.
34. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
35. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methoxyphenyl) - 4- oxobutanamide.
36. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - chlorophenyl) - 4- oxobutanamide.
37. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2,4 - dimethylphenyl) - 4- oxobutanamide.
38. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benztriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
39. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
40. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
41. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
13

42. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
43. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide.
44. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide.
45. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
46. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
47. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide.
48. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide.
49. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
50. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
51. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
52. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 -( 2 - thienyl)butanamide.
53. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
54. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
55. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - phenylbut - 2- enamide.
56. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - oxo- 4 - ( 4 - thiomethylphenyl )butanamide.
57. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - (2 - naphthyl) - 4 - oxobutanamide.
58. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide.
59. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
14

60. (S) - N -[ [ 3 - (3 - fluoro—4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
61. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbut - 2- enamide.
62. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
63. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide.
64. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide.
65. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
66. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - (4 - thiomethylphenyl)butanamide.
67. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - ( 2 - naphthyl) - 4 - oxobutanamide.
68. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
69. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide.
70. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
71. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
72. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
73. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
74. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
75. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
76. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
77. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
15

78. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 — oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide.
The respective N-oxides of the group R2 of the compounds of formula I listed above also form a novel aspect of the present invention.
The pharmaceutically active compounds of formula (I), the corresponding N-oxides of the group R2 and pharmaceutically acceptable salts thereof of this invention can be prepared by methods known to one skilled in the art.
Typically, compounds of formula (I), can be prepared by coupling of the amino fragment of formula (II)

Scheme-!
General method for synthesis of compounds of formula (I)

In a typical experiment, the amine compound of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinbefore is dissolved in a 1:1 mixture of tertahydrofuran and water or a 1:1 mixture of methylene chloride and water. To the solution is added the carboxylic acid compound of formula (III), followed by addition of 1-hydroxybenztriazole (HOBt). The resulting mixture is cooled to a temperature of 0-5° C to which l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 1.1 Eq.) is added and gradually allowed to warm to room temperature and agitated at this temperature for 24 hours. At the end of
17

the reaction, a solution of saturated aqueous sodium bicarbonate is added and the organic phase separated from the aqueous phase. Evaporation of the solvent and chromatography of the residue over silica gel affords compound of formula (I), generally as white solids.
The N-oxides of the group R2 of compound of formula (I) thus obtained are preferably prepared by addition of m-chloro perbenzoic acid (m-CPBA) to a cooled solution of the compound of formula (I) in a chlorinated hydrocarbon solvent such as methylene chloride and ethylene chloride and thereafter agitating the reaction mixture at room temperature for 12-15 hours. Evaporation of the solvent under reduced pressure, followed by chromatography of the residue over silica gel affords the corresponding N-oxides in high purity.
The N-oxides thus prepared, while retaining most of the antimycobacterial activity of the corresponding deoxo compound exhibit exceedingly high water solubility over the deoxo analogue, thereby helping in manufacture of suitable iv formulations, which forms an important aspect of this invention.
The starting materials required for synthesis of compound of formula (I), thus involve the amine compound of formula II and the carboxylic acid compound of formula III.
The amine compound of formula II can be selected from i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, vi) (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, and viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 -
oxazolidinyl] methyl amine.
18

The carboxylic acid compound of formula III can be selected from 4-(2-Naphthyl)-4-
oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic
acid, 4-oxo-4-(2'methylpropyl)phenylbutanoic acid, 4-Oxo-4-
(2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 - oxobutanoic acid,4 - (2,4 -
dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4-
chlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid,
4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 - phenyl - but - 2 - ynoic acid.
20

Thus, the starting amines of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinearlier are prepared as per the method disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33, 2569-2578; C. Wang et. al., Tetrahedron, 1989, 45, 1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO 95/25106 and WO 97,21708. The method is essentially summarized in Scheme-II.

In a typical method, morpholine, thiomorpholine, piperidine, 4-benzyl piperazine, pyrrolidine, 1,2,4-triazine, 12,3-benzotriazine, benzyl amine, a heterocycloalkyl or a heteroaryl moiety etc., each one of which corresponds to the group R2 defined hereinbefore is reacted with 3,4-difluoro nitrobenzene in the presence of a base and a solvent to give the corresponding derivative in which the fluorine atom at 4-position is substituted by the group R2. The nitro group in the compound thus obtained is reduced to amino group, which is thereafter protected by a suitable protective group. Reaction of the N-protected compound thus obtained with (R)-glycidyl butyrate in the presence of a strong base like n-butyl lithium leads to formation of the 5-hydroxymethyl oxazolidinone ring. The hydroxy group in the compound thus obtained is converted to sulfonyl derivative, for e.g. a methanesulfonyloxy (mesyl) or a p-toluenesulfonyloxy (tosyl) derivative by reaction with methanesulfonyl chloride or p-toluenesulfonyl chloride respectively. Reaction of the respective mesyl or tosyl derivative with sodium azide gives the corresponding azide, which is converted to the amine compound of formula (II) by standard methods, for e.g. by reaction with a triaryl/trialkyl phosphine, followed by hydrolysis.
The starting carboxylic acid fragments of formula (III), wherein the group Ar has the same meaning as defined hereinearlier are prepared as per the method disclosed in Org. Reactions, 1949, 5, 229-289; Quart. Rev. Chem. Soc, 1954, 8, 355-379; Chem. Rev., 1955, 55, 229-281, and J. Am. Chem. Soc, 1947, 69, 1784-1786. The method is essentially summarized in Scheme-HI.
Scheme-Ill General method for synthesis ofalkane and alkene carboxylic acid s of formula (HI)

In a typical method, the aromatic compound Ar-H, wherein Ar is as defined hereinbefore is reacted with succinic anhydride in the presence of a Lewis acid, such as anhydrous aluminium chloride and in the presence of an anhydrous solvent and the mixture heated to 100° C to give the carboxylic acid derivatives of formula (HI), wherein Q is alkyl of 1-4 carbon atoms.
23

Similarly, compounds of formula (III), wherein Q is an alkene (CH=CH) are prepared by reaction of the aromatic compound Ar-H, wherein Ar is as defined hereinbefore with maleic anhydride under the same conditions mentioned hereinbefore.
Compounds of formula (III), wherein Q is an alkyne (C=C) are prepared by reaction of propiolic acid ester with an aldehyde of formula Ar-CHO in the presence of butyl lithium and in the presence of an aprotic solvent such as THF at -78° C to give the corresponding secondary alcohol, which is oxidized to the keto derivative using manganese dioxide as the oxidizing agent. Saponification gives the carboxylic acid derivative of formula (ID) [ US 4,929,741 (A. Fischili et. al.) ] The synthesis is summarized in Scheme-IV.

P = any protective group
The synthesis of compound of formula (I) of this invention and the synthesis of the respective starting material amines of formula (II) and the carboxylic acids of formula (III) are further described herein in detail.
SYNTHESIS OF THE STARTING AMINES OF FORMULA OD
The amines were prepared as per the chemistry summarized in the Scheme-H and as per the methods disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33,2569-2578; C. Wang et. al., Tetrahedron, 1989, 45,1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO
24

95/25106 and WO 97,21708. Commercially available raw materials and known techniques were utilized for the synthesis.
The optically pure amines as such were obtained by using optically active intermediates or resolution of racemic mixtures by a suitable reagent. The preferred enantiomer is (S), at the chiral centre on the oxazolidinone ring.
Example 1 General Method for Preparation of the Amines (II)
The oxazolidinone azides of general formula (8), given in Scheme-II (1.0 eq) were dissolved in dry THF (10 times by volume ) and treated with triphenyl phosphine (1.5 eq.) at room temp. The resulting solution was stirred for 6hrs at room temp. Water [2 eq. of (8)] was added and the solution heated for 6hrs at 55 - 60° C. The solvent was evaporated and the residue chromatographed on a column of silica gel (100 -200 mesh) and eluted initially with ethyl acetate and then with chloroform : methanol (4:1) to give the the amines (II) as white solids.
The following amines i) to viii) of formula I were prepared by this general method, viz.
i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, vi) (S) - N -[3 - (3 - fluoro — 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, and
viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 -
oxazolidinyl] methyl amine.
SYNTHESIS OF THE STARTING CARBOXYLIC ACIDS OF FORMULA (HP
Example 2 4-(2-Naphthyl)-4-oxobutanoic acid
Naphthalene (5.0gm, 0.039moles) and succinic anhydride (4.68gm, 0.0468 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (11.44g, 0.0858 moles) was added at
25

room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 25 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid. Subsequent column chromatography gave a buff coloured solid. Subsequent chromatography gave 3.7 gm (41%) the title compound, mp 173-174° C.
'H NMR (CDCI3, 5) : 8.40 (s,lH), 7.7 - 8.0 ( m, 4H), 7.4 - 7.6 (m,2H), 3.33 (t,2H), 2.77 (t,2H + 1H).
The filterate was concentrated to give 5.8 gm of a mixture of 4-(2-naphthyl)-4-oxobutanoic and 4-(l-naphthyl)-4-oxobutanoic acid.
Example 3 4- Oxo-4-(2- ThienylJbutanoicacid
Thiophene (5.0gm, 0.059moles) and succinic anhydride (7.13gm, 0.0713 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (17.43gm, 0.131 moles) was added at room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 30 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (50 ml). The solid was dried at room temp to give 9.8 gm (89%0 of the title compound, mp 103 - 107° C.
!H NMR (CDCI3, 8) : 7.69 (dd, 1H), 7.58 (dd, 1H), 7.07 (dd,lH), 3.9 (bs, 1H), 3.23 (t, 2H), 2.74 (t,2H).
Example 4 4- Oxo-4-(4-thiomethyl)phenylbutanoic acid
Thiophenol methyl ether (8.0gm, 0.0645moles) and succinic anhydride (7.75gm, 0.0774 moles) were taken up in dichloroethane (80 ml). Aluminium chloride (18.90gm, 0.1419 moles) was added at room temperature. The resulting mixture stirred for 0.5hr and then heated at 85° C for lhr. The reaction mixture was cooled to room temperature, diluted with 40 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (80 ml). The solid was dried at room temp to give 6.9 gm (48%) of the title compound, mp 151 -154° C. *H NMR (CDCI3, 5) : 7.82 (d,2H), 7.20 (d, 2H), 4.2 (bs, 1H), 3.21 (t, 2H), 2.73(t, 2H),2.45 (s,3H).
26

Example 5 4 - oxo -4- (2'methylpropyl)phenylbutanoic acid
2'methylpropylbenzene (5.0m, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles), were taken up in dichloroethane (50 ml). Aluminium chloride (10.90g, 0.0821 moles ) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 ml of a 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.7 gm (99%) of the title compound as a solid, mp 102 - 105° C.
!H - NMR (CDC13, 8) : 7.83 (d,2H), 7.17(d,2H), 3.24(t,2H), 2.74(t, 2H), 2.46 (d, 2H), 1.80 (pent., 1H).
Example 6 4 - Oxo - 4 - (2',2'dimethylethyl)phenylbutanoic acid
2',2'dimethylethylbenzene (5.0gm, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (10.90gm, 0.0821 moles) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 m of a 1:1 mixture of water Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.5 gm (97%) of the title compound as a solid, mp 103 — 107° C. !H-NMR (CDCI3,8) : 7.94(d,2H), 7.50 (d, 2H), 3.29 (t,2H), 2.82 (t,2H), 1.36 (s,9H).
Example 7 Using the appropriate aromatic compound (Ar-H) and succinic anhydride and following exactly the method described in Examples 2-6 the following carboxylic acids can be prepared, viz.
i) 4 -(4 -methylphenyl)- 4 - oxobutanoic acid,
ii) 4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid, iii) 4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid, iv) 4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, v) 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, vi) 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid, vii) 4 -{2- Naphthyl)- 4 - oxobutanoic acid, viii) 4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, ix) (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and x) 4 - oxo - 4 - phenyl - but - 2 - ynoic acid.
27

SYNTHESIS OF THE COMPOUNDS OF FORMULA (D
Example 7
Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - J -
oxazolidinyl ] methyl] — 4-(4- naphthyl) -4- oxobutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 dichloromethane-water mixture (10 ml). To this was added 4 -( 2 - naphthyl- 4 - oxobutanoic acid (0.154gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) the resulting mixture was cooled to 0° C. l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added the resulting mixture was allowed to warm to room temperature and then stirred for 24hr. Saturated aqueous sodium bicarbonate solution (2ml) was added to the reaction mixture, stirred for 15 min and then the organic layer separated and the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.22 gm, 64%) as a white solid. MS (M+l) = 506 m/z
*H NMR (CDC13, 5) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, 1H ), 7.01(dd,lH ), 6.74 (t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, 1H), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91 (m,4H), 2.60(t, 2H).
Example 8
Preparation of (S) -N-[[3- (3-fluoro-4-morpholinylphenyl) -2-oxo-5-
oxazolidinyl ] methyl] -4- oxo -4-(2- thienyl)butanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml) . To this was added 4 - oxo - 4 (2 - thienyl)butanoic acid (0.125gm, 0. 00068 moles) and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the resulting mixture was allowed to warm to room temp and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated sodium bicarbonate was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separatedand the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.175 gm, 56%) as a white solid
MS (M+1) = 462 m/z
28

lH NMR (CDC13, 8) : 7.63(d,lH ), 7.55 (dd,lH ), 7.35(dd,lH), 7.04(t, like dd, 2H), 6.83(t,lH), 6.30 (t,lH), 4.69(m,lH), 3.93 (t, 1H), 3.6- 3.8 (m, 3H),3.80 (m,4H), 3.61(dd, 2H), 3.21(dd,2H),2.97 (m,4H),2.55(t, 2H).
Example 9
Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -
oxazolidinyl ] methyl ] - 4 - [4 - ( V- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 -oxo - 5 -oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml). To this was added 4 - [ 4(2'-methylpropylphenyl)]- 4 - oxobutanoic acid (0.158gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated, and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.210gm, 60%) as a white solid.
MS(M=l) = 512m/z
'H NMR (CDC13, 8) : 7.73(d,2H ), 7.52 (dd,lH ), 7.28(m,lH ),7.15(d,2H ), 7.05 (d,lH), 6.39 (t,lH), 4.75(m,lH), 3.91 (m, 4H), 3.5- 3.9 (m, 4H), 3.28 (dd, 2H), 3.16 (m,4H),2.54 (t, 2H), 2.45 (d, 2H), 1.82 (pent., 1H), 2.60 (t, 2H).
Example 10
Preparation of(S) -N-[ [3 - (3 -fluoro -4- morpholinylphenyl) - 2 -oxo - J -
oxazolidinyl J methyl J -4- oxo - 4 -(4- thiomethyl) phenylbutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF -water mixture (20 ml). To this was added 4 - (4-methlythiophenyl) - 4 - oxobutanoic acid (0.152g, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) and the resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142g, 0.00074 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate was added to, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The
29

combined fractions were concentrated to give the title compound (0.270 gm, 79%) as a white solid.
MS (M+l) = 502 m/z
JH NMR (CDC13, 5) : 7.70(d,2H ), 7.37 (dd,lH ), 7.14(d,2H ), 7.00 (dd,lH), 6.79(t,lH), 6.38 (t,lH), 4.71(m,lH), 3.86(t,lH),3.5- 3.9 (m, 4H), 3.81 (m, 4H), 3.22 (dd, 2H), 2.96 (m,4H),2.53 (t, 2H), 2.45(s,3H).
Example 11
Preparation of:. (S) - N-[[3 - (3 -fluoro -4- morphottnylphenyl) — 2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) - 4 - oxobutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.100gm, 0.00034 moles) was taken up in 1:1 THF-water mixture (20 ml) . To this was added 4 - (4- chlorophenyl) - 4 - oxobutanoic acid(0.072g, 0.00034 moles and HOBt (0.046g, 0.00034 moles) .The resulting mixture was cooled to 0°C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.071gm, 0.00037 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated and 2 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with dichloromethane. The organic layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give (0.070gm, 42%) of the title compound as a white solid.
MS (M+l) = 490 m/z
JH NMR (CDCI3, 8) : 7.72(d,2H ),7.37 (dd,lH ),7.31(d,2H ), 6.98 (dd,lH),6.79 (t,lH), 6.28
(t,lH), 4.69(m,lH), 3.83 (t, 1H), 3.81 (m, 4H), 3.4- 3.m (m, 3H), 3.21 (dd, 2H), 2.97 (m,4H),2.54
(t,2H).
Example 12
Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -
oxazolidinyl ] methyl ] - 4 - ( 2 -naphthyl) - 4 - oxobutanamide - N - oxide.
To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -
2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (2 -naphthyl) - 4 - oxobutanamide (0.950gm, 0.0019
moles) in dichloromethane (150 ml) was added 60% m -CPBA (0.550g, 0.0032 moles) and the
resulting solution stirred at room temperature for 12hr. The solvent was evaporated under
reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The
column was eluted with ethyl acetate (200 ml), followed by a mixture of chloroform : methanol
30

(4:1,600 ml).Concentration the combined fractions gave the title N-oxide (0.891g, 82% ) as a
white solid.
!H NMR (CDCI3, 8) : 8.59(t,lH ), 8.36(s,lH),7.7-7.9 (m,5H), 7.2 -7.5 (m,2H),7.08 (dd,lH),
6.60(t,lH), 4.76(m,lH), 4.61(bt,2H), 3.5 - 4.3 (m, 9H), 3.42 (dd, 2H), 2.83 (bdd,2H), 2.61 (bt,
2H).
Example 13
Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide. To a cooled solution (0 - 5° C) of (S) - N -[[3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - oxo - 4 - (2 - thienyl)butanamide (0.850gm, 0.0017moles) in dichloromethane (120 ml) was added 60% m -CPBA (0.550g,0.0032 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The column was eluted with ethyl acetate (200ml) followed by a mixture of chloroform : methanol (4:1,600 ml).Concentration of the combined fractions gave the tile N-oxide (0.790g, 90%) as a white solid.
1HNMR( CDCI3,5) : 8.63(t,lH), 7.77(dd,lH), 7.65 (d, 1H), 7.56 (d, 1H), 7.09 (dd, 1H),7.04 (dd,lH), 6.45(t,lH), 4.68(m,lH), 4.65(bt,2H), 4.22 (dt,2H), 3.89(t,lH), 3.5 - 3.9 (m, 5H), 3.22 (dd, 2H), 3.00 (bd,2H), 2.54 (t, 2H).
Example 14 Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) -4- oxobutanamide -N- oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide, (1.150gm, 0.0023 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.725gm, 0.0040 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1,600 ml). Concentration of the combined fractions gave the title N-oxide (0.950g, 80%) as a white solid.
'HNMRtCDCk 8) : 8.61(t,lH ), 7.76(d,2H), 7.72 (dd, 1H), 7.34 (d, 2H), 7.10 (dd, 1H), 6.46(t,lH), 4.70(m,lH), 4.64(bt,2H), 4.16 (dt,2H), 3.94(t,lH), 3.5 - 3.9 (m, 5H), 3.24 (dd, 2H), 2.97 (bd,2H), 2.55 (t, 2H).
31

Example 15 Preparation of(S) -N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo -5-oxazolidinyl ] methyl] -4-/4-(2'- methyl - 4 -propylphenyl) -4 — oxobutanamide -N-
oxide.
To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - [4 - (2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide (1.05gm, 0.0020 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.600gm) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1 , 600 ml). Concentration of the combined fractions gave the title N-oxide (0.891gm, 82%) as a white solid.
JH NMR (CDC13, 5) : 8.62(t,lH ), 7.77(dd,lH), 7.75 (d, 2H), 7.14 (d, 2H), 7.12 (dd, 1H), 6.44(t,lH), 4.75(m,lH), 4.64(bt,2H), 4.20 (dt,2H), 3.95(t,lH), 3.91 (t,lH) 3.5-3.9 (m, 4H), 3.26 (dd, 2H), 2.99(bd,2H), 2.57 (t, 2H),2.44(d,2H), 0.83(d,6H).
Example 16 Preparation of (S)-N-ff3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4-
methylphenyl)-4-thiooxobutanamide
To a solution of (S)-n- of (S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4-methylphenyl)-4-oxo-butanamide (0.1 Ogm, 0.00021 moles) in dry THF (5ml) was added Lawessons Reagent (0.052gm, 0.000128 moles) and the resulting solution heated under reflux for 8 hr. The reaction mixture was cooled to room temperature and to this was added saturated aqueous sodium carbonate solution (3ml) and then extracted with ethyl acetate. The solvent was evaporated off and the residue chromatographed over silica gel and eluted with a mixture of ethyl acetate-hexane to give the title compound (0.023 gm, 23%) as a white solid, mp 149-151° C.
lH NMR (CDCI3,5) : 8.60 (m, 1H), 7.68 (d, 2H), 7.34 (dd, 1H), 7.14 (d, 2H), 6.96 (dd, 1H), 6.81 (t, 1H), 4.90 (m, 1H), 4.20-4.40 (m, 1H), 3.80-4.0 (m, 4H), 3.50 (m, 2H), 2.90-3.00 (m, 6H).
Example 17 Using the appropriate amine compound (II) and the carboxylic acid (HI) and following exactly the method described in Examples 7-16 the following carboxylic acids can be prepared, viz.
(S) - N-[ [ 3 - (3-fluoro — 4- morpholinylphenyl) -2- oxo — 5- oxazolidinyl J methyl] — 4-(4- methylphenyl) -4- oxobutanamide.
32

'H NMR (CDCI3, 5) : 7.78 (d, 2H ), 7.44 ( d, IH ), 7.22 ( d,2H ), 7.09 ( d, IH ), 6.88 ( t, IH ), 6.41(t, IH), 4.76 (m, IH ), 3.6 - 4.1 (m, 4H ), 3.86 ( m, 4H ), 3.31 ( dd, 2H ), 2.61 (t, 2H ), 2.40 (s.3H).
(S) -N-[[ 3-(3 -fluoro -4 - benzylpiperazinyl) phenyl] -2- oxo - 5 - oxazolidinyl] methy ] -4-oxo -4-phenylbutanamide.
lH -NMR (CDC13, 5) : 7-88 ( d,2H ), 7.61 (dd, IH), 7.38 ( m, 5H ), 7.2 - 7.4 (m, 5H), 6.88 (t, IH ), 6.55 (t, IH ), 4.77 ( m, IH), 3.94 (t, IH), 3.5 - 3.7 (m, 3H ), 3.71 ( s, 2H ), 3.34 (dd, 2H ), 3.12 (m, 4H),3.12 (m, 4H ), 2.61 (t, 2H ).
(S) - N-f]3 - ( 3 -fluoro - 4 - [methylbenzylamin]phenyl) - 2 - oxo -5 - oxazolidiny] methy ]-4-(4- methyl phenyl) -4- oxobutanamide.
*H NMR (CDCI3, 8) : 7.90 ( d, 2H ), 7.52 ( dd, IH ), 7.2 - 7.5 ( m, 8H ), 7.05 ( d, IH ), 6.84 (t, IH ), 6.50 (t, IH ), 4.75 (m, IH ), 4.48 (s, 2H ), 3.95 (t, IH), 3.6 - 4.1( m,3H ), 3.64 ( dd, 2H ), 2.71 (s,3H), 2.62 (t,2H).
(S)-N-[[3-(3-fluoro-4- benzotriazolylpheny)-2-oxo-5-oxazolidinyl]methy]-4-oxo - 4 -phenylbutanamide.
!H NMR ( CDCI3, 5) : 8.16 ( d,lH), 7.84 (d, 2H), 7.66 (t, IH), 7.2 -7.6 (m, 8H), 6.46 (t, IH ), 4.90 (m, IH), 3.98 (t,lH), 3.9 - 4.0 (m, 2H ), 3.65 (m, IH ), 3.39 (ddd, 2H ), 2.65 ( ddd, 2H). (S) -N-[[3-(3-fluoro-4- pyrrolidinylphen) -2-oxo-5- oxazolidinyl]methyl]-4-oxo - 4 -phenylbutanamide.
!H NMR (CDCI3, 8) : 7.90 (d,2H ), 7.52 (dd, IH ), 7.44 (d, 2H ), (dd, IH ), 7.04 (dd, IH), 6.65 (t, IH), 6.43 (t, IH), 4.74 (m,lh), 3.93 (t,lH), 3.77 (t,lH), 3.6 3,8 (m, 2H), 3.33 (m, 6H ), 2.63 (t, 3H), 1.94 (m,4H).
(S)-N-[[3-(3-fluoro-4- benzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methy]-4-(4- methlyphenyl) - 4- oxobutanamide.
!HNMR (CDCU, 8) : 8.16 (d, IH ), 7.3 - 7.9( m,7H), 7.78 (d,2H ), 7.21(d,lH), 6.54(t, IH), 4.89 ( m, IH), 3.8 -42 (m, 3H ), 3.4 - 3.7 (m, 3H ), 2.63 (dd, 2H ), 2.23 (s, 3H ). (S)-N-][3-(3 -fluoro - 4 - thiomorpholinylphenyl) -2 — oxo - 5 - oxazolidinyl] methyl] -4- oxo- 4 -phenylbutanamide.
!H NMR (CDCI3, 8) : 7.89 (d, 2H ), 7.39 - 7.60 ( m, 4H ), 7.11 (dd, IH ), 6.90 (t, IH), 6.39 ( t,lH ), 4.76 (m,lH ), 3.94 (t,lH ), 3.80 (t, IH ), 3.6 - 3.7 ( m, 2H ), 3.36 ( dd, 2H ), 3.28 ( m,4H), 2.80 ( m,4H ), 2.62 (t, 2H).
(S) — N-[[3 - (3 -fluoro - 4 - benzylpiperazinyl) phenyl] — 2 — oxo — 5 - oxazolidinyl] methyl]- 4-(4- methylphenyl) -4- oxobutanamide.
33

*H NMR (CDCI3, 5) : 7.81 ( d, 2H), 7.2 - 7.5 ( m, 8H ), 7.08 (dd, IH ), 6,89 (t, IH ), 6.39 (t, IH
), 4,78 ( m, IH ), 3.95( t, IH), 3.79 (t, IH), 3.6 - 3.7 (ni, 2H ), 3.61(s, 2H), 3.31 ( m,2H), 3.09
(m,4H), 2.65 (m,6H), 2.41 (s, 3H).
(S)-N-[[3-(3-fluoro-4- piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl]-4-
oxo - 4 - phenylbutanamide.
!H NMR (CDCI3, 8) : 7.90(d,2H ),7.60 (dd,lH ),7.45(d,2H ), 7.39 (dd,lH), 7.10 (dd,lH), 6.90
(t,lH), 6.55 (t,lH), 4.78(m,lH), 3.95 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.35 (m, 2H), 3.00
(m,4H0,2.63 (t, 2H), 1.9-1.6 (m,6H).
(S)-N-[[3- (3 -fluoro-4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4-(4
- methylphenyl) - 4- oxobutanamide.
JH NMR (CDCI3, 5) : 7.79(d,2H ),7.40 (dd,lH ),7.23(d,2H ), 7.09 (dd,lH), 6.91 (t,lH), 6.40
(t,lH), 4.77(m,lH), 3.98 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.30(t, 2H), 2.98 (m,4H), 2.62 (t,
2H),2.41(s,3H), 1.6-1.9 (m,6H).
(S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5- oxazolidinyl] methyl]- 4
-(4- methylphenyl) - 4- oxobutanamide.
'H NMR (CDCI3, 8) : 7.80(d,2H ),7.32 (dd,lH ),7.21(d,2H ), 7.01 (dd,lH), 6.60 (t,lH), 6.40
(t,lH), 4.75(m,lH),4.12(m,lH) 3.94 (t, IH), 3.75 (t, IH), 3.4- 3.6 (m, 2H), 3.34 (m, 6H), 2.61 (t,
2H),2.40(s,3H), 1.9(m,4H).
(S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4
-(4- methoxyphenyl) -4- oxobutanamide.
lU NMR (CDCI3, 8) : 7.79(d,2H ),7.36 (dd,lH ), 7.00 (dd,lH), 6.82 (d,2H), 6.80(t,lH), 6.38
(t,lH), 4.69(m,lH), 3.80 (s, 3H), 3.78 (m, 4H), 3.4- 4.0 (m, 4H), 3.20 (dt, 2H), 2.97 (m,4H),2.55
(dt,2H).
(S) -N-[[3-(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-
(2 -naphthyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, IH ), 7.01(dd,lH ), 6.74
(t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, IH), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91
(m,4H), 2.60(t, 2H).
((S) - N -[[ 3 - (3 -fluoro -4- morpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-
(2, 4-difluorophenyl) -4-oxobutanamide.
!H NMR (CDCI3, 8) : 7.73(ddd,2H ), 7.47 (dd,lH ), 7.01(dd,lH ),6.7 - 6.9(m,3H ), 6.30 (t,lH),
4.75(m,lH), 3.89 (m, 4H), 3.5- 3.9 (m, 4H), 3.20 (m, 2H), 3.09(m,4H), 2.52 (t, 2H).
(S)-N -[[ 3-(3 -fluoro -4- morpholinylphenyl) -2- oxo -5— oxazolidinyl] methyl] - 4
-[4- (2s',2'- dimethyl- 4 - ethylphenyl) -4- oxobutanamide.
34

!H NMR (CDC13, 8) : 7.75(d,2H ), 7.37 (d,2H ), 7.35(dd,lH ), 7.05 (dd,lH), 6.82(t,lH), 6.37
(t,lH), 4.71(m,lH), 3.5- 3.9 (m, 4H), 3.80 (m, 4H), 3.25 (dt, 2H), 2.97 (m,4H),2.54 (t, 2H),
1.26(s,9H).
(S) -N-ff 3 - (3 -fluoro - 4 -fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl] -4-(4- methoxyphenyl) -4- oxobutanamide.
lU NMR (CDC13, 8) : 7.76(d,2H ), 7.37 (dd,lH ), 7.16(m,5H ), 6.93 (dd,lH), 6.79(d,2H),6.74 (
t,lH), 6.37 (t,lH), 4.66(m,lH),4.14 (s,2H), 3.84(t,lH), 3.74 (s,3H), 3.4- 3.8 (m, 3H), 3.18 (dd,
2H), 2.62(s,3H),2.5 l(t, 2H).
(S) -N-ff 3 - (3 -fluoro - 4 - fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl]
methy] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide.
'H NMR (CDCU, 8) : 7.77(d,2H ), 7.37 (dd +d,3H ), 7.19 -7.22(m, 3H), 6.98 (dd,lH),
6.77(t,lH), 6.31 (t,lH), 4.69(m,lH), 4.17(s,2H), 3.89(t,lH)„3.72 (dd,lH), 3.5- 3.6 (m, 2H), 3.25
(dd, 2H), 2.64 (s,3H),2.55 (t, 2H), 1.25(s,9H).
(S) -N-ff 3 -(3 -fluoro - 4 -[methylbenzylamino]phenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl] -4- (2,4 - dimethylphenyl) -4- oxobutanamide.
lU NMR (CDCI3, 8) : 7.65(d,lH ), 7.46 (dd,lH ), 7.32(m,5H ), 7.04(m,3H), 6.95(t,lH), 6.36
(t,lH), 4.78(m,lH), 4.27(s,2H), 3.97(t,lH),3.6- 3.8 (m, 2H), 3.81 (t, IH), 3.27 (dd, 2H), 2.77
(s,3H),2.61 (t, 2H), 2.44(s,3H), 2.35 (s, 3H).
(S)-N -[[ 3-(3 -fluoro -4- tnorpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] - 4
- (2,4 - dimethylphenyl) -4- oxobutanamide.
'H NMR (CDCU, 8) : 7.652(d,lH ), 7.42 (dd,lH ), 7.0- 7.1(m,3H), 6.86(t,lH), 6.38 (t,lH),
4.79(m,lH), 3.95(t,lH),3.5- 3.9 (m, 2H), 3.87 (m, 4H), 3.25(dd, 2H), 3.02 (m,4H), 2.59 (t, 2H),
2.41(s,3H), 2.34 (s, 3H).
^ -N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) —2 — oxo -5 — oxazolidinyl] methyl] — 4 —
(2,4 - dimethylphenyl) - 4 - oxobutanamide.
JH NMR (CDCI3, 8) : 7.62(d,lH ), 7.31 (dd,lH ), 7.03(s,+dd, 3H ), 6.60(t,lH), 6.36 (t,lH),
4.74(m,lH), 3.94(t,lH), 3.76 (dd, lH),3.67(m, 2H), 3.30 (m, 4H), 3.24 (dt, 2H), 2.60 (t, 2H),
2.44(s,3H), 2.34 (s, 3H).1.94 (m,2H).
(S) -N-ff 3-(3-fluoro-4- benztriazolylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4-
(2,4- dimethylphenyl) -4-oxobutanamide.
!H NMR (CDCI3, 8) : 8.15(d,lH ), 7.80 (dd,lH ), 7.3 -7.7(m,6H ), 7.02(d,2H), 6.39 (t,lH),
4.87(m,lH), 4.07(t,lH), 3.96(t,lH), 3.89 (dq, IH), 3.75(dt,lH), 3.38 (qt, 2H), 2.62 (m, 2H),
2.39(s,3H), 2.26 (s, 3H).
(S) - N-ff 3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-
oxo -4-(2- thienyl)butanamide.
35

*H NMR (CDC13, 8) : 7.71(d,lH ), 7.63 (d,lH ), 7.31(dd,lH ), 7.11 (t, lH),7.05(dd,lH), 6.68(m,lH), 6.38 (t,lH), 4.74(m,lH), 3.95(t,lH), 3.77 (t, 1H),3.6- 3.7 (m, 2H), 3.36 (m, 4H), 3.28 (t, 2H), 2.63 (t, 2H), 1.96 (m,2H). (S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo - J - oxazolidinyl] methyl] - 4
- oxo -4-(2- thienyl)butanamide.
!H NMR (CDC13, 8) : 8.08(d,lH), 7.77(dd,lH ), 7.3 - 7.7(m,7H ), 7.02(t,lH), 6.45 (t,lH),
4.81(m,lH), 4.00(t,lH),3.7- 4.0 (m, 2H), 3.57 (dt, 1H), 3.25 (m, 2H), 2.55 (m,2H).
(3? -N-[[3-(3-fluoro-4- morpholinylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4-
oxo - 4 -phenylbut - 2- enamide.
JH NMR (CDCI3, 8) :7.92 (d,lH), 7.84 (,d,lH), 7.2 - 7.6 (m, 6H), 6.98 - 7.1 (m, 3H), 4.38(m,
1H), 3.5 - 4.1 (m, 4H), 3.84 (m, 4H), 3.03 (m, 4H).
(S) -N-[[3-(3 -fluoro-4- piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4-(4
- methoxyphenyl) - 4- oxobutanamide.
'HNMR^MSOde, 8) : 8.25 (t, 1H), 7.79 (d, 2H), 7.38 (dd, 1H), 7.71 (dd, 1H), 6.95 (t,lH), 6.93
(d, 2H + 1H), 4.65 (m,lH), 3.75 (s,3H), 3.99 (t, 1H), 3.64 (dd, 1H), 3.06 (t, 2H), 2.81(m,4H), 1.3
-1.6(m.6H).
(S) -N-[[3-(3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4
- chlorophenyl) - 4- oxobutanamide.
lH NMR (CDCI3, 8) : 7.73(d,2H ), 7.33 (d,2H ), 7.2 - 7.8 (m, 2H),6.96(dd,lH), 6.34 (t,lH), 4.72(m,lH), 3.84(t,lH), 3.5- 3.8 (m, 3H), 3.21 (dd, 2H), 2.98 (m, 4H),2.54(t,2H), 1.5 - 1.7 (m,6H).
(S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl] -4-(2,4 - dimethylphenyl) - 4- oxobutanamide.
'H NMR (CDCI3, 8) : 7.55(d,2H ), 7.4 (m,lH ), 6.9 - 7.0 (m, 3H),6.32(t,lH), 4.70(m,lH), 3.90(t,lH), 3.74 (t,lH), 3.5- 3.7 (m, 2H), 3.20 (dd, 2H), 2.9 - 3.1 (m, 4H),2.52(t,2H), 2.34 ( s,3H), 2.71 (s, 3H ), 1.5 -1.9 (m,6H).
(S) - N-[[3 - (3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- methoxyphenyl) -4-oxobutanamide.
XH NMR ( CDCI3, 8) : 8.07(d, 1H), 7.2 - 7.8 (m,6H), 7.71(d,2H ), 6.79 (d,2H ), 6.51(t,lH), 4.81(m,lH), 3.4- 4.0 (m, 4H), 3.71 (s, 3H), 3.15 (qt, 2H), 2.52 (dd, 2H).
(S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- chlorophenyl) -4-oxobutanamide.
'H NMR (CDCI3, 8) : 8.09(d, 1H), 7.2 - 7.8 (m,6H), 7.75(d,2H ), 7.35 (d,2H ), 6.29(t,lH), 4.81(m,lH), 3.7 - 4.0(m, 3H), 3.5 - 3.7 (bt, 1H),3.25 (qt, 2H), 2.55 (t, 2H). (S)-N-[[3-(3-fluoro-4-(1,2,4-triazolyl)phenyl)-2-oxo-5- oxazolidinyljmethyl] -4- oxo — 4 - phenylbutanamide.
36

*H NMR (CDCI3, 8) : 8.62 (bs, 1H ), 8.10 ( s, 1H ), 7.7 -7.8 ( m, 2H ),, 7.67 (dd, 2H, ), 7.44 (t,
1H ), 7.2 - 7.4 (m,3H ), 6.49 (t, 1H ), 4.78 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55 (dt, 1H ), 3.30 (ddd,
2H), 2.54 (dd, 2H).
(S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4-(4- methylphenyl) -4- oxobutanamide.
XHNMR (CDC13, 8) : 8.71 (bs, 1H ), 8.10 ( s, 1H), 7.7 -7.9 ( m, 4H ), 7.30 (d, 1H, ), 7.21 (d, 2H
), 6.63 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.64(dt, 1H ), 3.35 (qdd, 2H), 2.5 - 2.6 (m, 2H),
2.35( s,3H).
(S) - N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -
4-(4- methoxyphenyl) -4- oxobutanamide.
'H NMR (CDCI3, 8) : 8.68 (bs, 1H ), 8.16 ( s, 1H ), 7.7 -7.9 ( m, 2H ), 7.79( d, 2H ) 7.28 (dd,
1H), 6.85 ( d,2H), 6.58 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.82(s,3H), 3.61(dt, 1H ), 3.32
(qdd, 2H), 2.65 (ddd, 2H).
(S) -N-][3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl]
-4-(2,4- dimethylphenyl) -4- oxobutanamide.
!HNMR (CDCI3,8) : 8.69 (bs, 1H ), 8.17 ( s, 1H ), 7.78( t,lH), 7.75 ( d,lH ), 7.60 (d,lH),7.25(d,
1H, ), 7.10 (d, 1H ),6.99(s, 1H ), 6.54( t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.65(dt, 1H ),
3.25 (qt, 2H), 2.59 (dt, 2H), 2.38( s,3H), 2.29 (s,3H).
(S) -N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4- oxo- 4 -(4 - thiomethylphenyl)butanamide.
'H NMR (CDCI3, 8) : 8.57 (bs, 1H ), 8.06 ( s, 1H ), 7.77 (m,2H), 7.61 (d, 2H), 7.19 ( d, 1H ),
7.10 (d, 2H, ), 6.47 (t, 1H ), 4.76 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25 (qdd, 2H), 2.55
(dq,2H),2.39(s,3H).
(S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide.
lU NMR (CDCI3, 8) : 8.58 (bs, 1H ), 8.06 ( s, 1H ), 7.80(t,lH),7.6 -7.8 ( m, 1H ), 7.67 (d,
2H,),7.32(d,2H), 7.26 (d, 1H ), 6.43 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25
(qt, 2H), 2.53(dt, 2H), 1.22( s,9H).
(S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo -5- oxazolidinyl] methyl]
-4-(2'- methyl - 4 - propylphenyl) -4- oxobutanamide.
'H NMR (CDCI3, 8) : 8.61 (bs, 1H ), 8.09 ( s, 1H ), 7.6 -7.8 ( m, 4H ), 7.24 (dd, 1H, ), 7.07 (d,
2H ), 6.38 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.54(dt, 1H ), 3.28(qt, 2H), 2.54(dt, 2H),
2.40( d,2H), 1.77 (pent.,lH), 0.81 (d,6H).
(S) - N-[[ 3-(3 -fluoro -4- (1,2,4 — triazolyl) phenyl) -2- oxo -5— oxazolidinyl] methyl]
-4-oxo - 4- (2- thienyl)butanamide.
37

'HNMR (CDCI3, 8) : 8.57 (bs, IH ), 8.05 ( s, IH ), 7.76 (t,lH),7.60(dd,lH), 7.53 (dd,lH), 7.25
(dd, IH, ), 7.01 (d, 2H ), 6.47( t, IH ), 4.78 ( m, IH), 3.7 - 4.0 (m, 3H), 3.56(ddd, IH ), 3.25 (qt,
2H), 2.54 (dt, 2H).
(S) -N-[[3 -(3 -fluoro -4- (1,2,4-triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl]-
4 - (2-naphthyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) : 8.41 (s, IH ), 8.27( s, IH ), 8.02(s,lH), 7.3 -7.9 ( m,6H ), 7.3 - 7.6 (m,
3H), 6.44 (t, IH ), 4.77 ( m, IH), 3.7 - 4.0 (m, 3H), 3.2- 3.7 (m, 3H), 2.5-2.6 (m, 2H).
(S) - N-[[3 - (3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4-(4- chlorophenyl) -4- oxobutanamide.
lH NMR (CDCI3, 8) : 8.58 (bs, IH ), 8.07 ( s, IH ), 7.6 -7.9 ( m, 2H ), 7.68 (d, 2H), 7.29 (d,
2H,), 7.2 - 7.3 (m, IH ), 6.31 (t, IH ), 4.81 ( m, IH), 3.7 - 4.1 (m, 3H), 3.55(dt, IH ), 3.25 (qt,
2H), 2.55(dt, 2H).
(S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4-
oxo -4-(2- thienyl)butanamide.
*H NMR (CDCI3, 8) : 7..5 - 7.7 ( m, 2H), 7.3 - 7.5 (m,lH), 6.8 - 7.3(m,3H ), 6.35(t,lH),
4.69(m,lH), 3.89 (t,lH), 3.76(t,lH),3.59(m,2H), 3.21(dd,2H),3.02 (m, 4H), 2.55 (t, 2H), 1.5 -
1.8 (m,6H).
(S) -N-[[3 -(3-fluoro -4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4-
(2'- methyl -4- propylphenyl) -4- oxobutanamide.
'H NMR (GDCI3,8) : 8.08 (m, IH ), 7.74 (d, 2H), 7.4 - 7.8 (m, IH ), 7.16 (d, 2H,), 6.97(dd,lH)
6.37 (t, IH ), 4.74 ( m, IH), 3.88 (t, IH), 3.80(t,lH), 3.4 - 3.71 (m, 2H), 3.40(m,4H) 3.25(dd, 2H
), 2.45(d, 2H), 1.80 (pent, IH), 1.5-1.8(m,6H),0.83(d,6H).
(S)-N-[[3-(3-fluoro-4-piperidylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(4
- acetamidophenyl) -4- oxobutanamide.
'H NMR (DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.78 (d, 2H), 7.60 ( d, 2H), 7.36 (dd, IH),
7.06 (dd, IH), 6.93 (t,lH), 4.63 (m, IH), 3.95(t,lH), 3.61 (dd,lH), 3.07(dd,lH), 2.81 (m,4H),
1.99 (s, 3H), 1.55 (m, 4H), 1.44 (m, 2H).
(S) - N-ff 3 -( 3 -fluoro - 4 * piperidylphenyl) - 2 - oxo - J - oxazolidinyl] methyl] -4-
oxo - 4 -phenylbut - 2- enamide.
JHNMR (CDCI3, 8) .-7.7-8.0 (m,3H), 7.2 - 7.6 (m, 5H), 7.01 (d,2H), 6.98 (t, IH), 4.80(m, IH),
4.01(t,lH), 3.85(t,lH), 3.77 (t, 2H), 3.16 (m, 4H), 1.5 - 1.9 (m,6H).
(S) - N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] ~4-
oxo- 4-(4- thiomethylphenyl)butanamide.
lU NMR (CDCI3, 8) :7.70 (d,2H), 7.60 (bd,lH), 7.0 - 7.3 (m, 3H), 6.91 (d,lH), 6.47 (t, IH),
4.71(m, IH), 3.87(t,lH), 3.4 - 3.8 (m,3H ), 3.45(m, 4H) 3.21 (dd, 2H), 2.54 (t, 2H), 2.45 (s,3H),
2.06(m,4H).
38

(S)-N-[[3-(3-fluoro-4-pyrrolidinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(2-naphthyl) -4- oxobutanamide.
!H NMR (CDC13, 8) : 8.35 (s, IH ), 7.5 - 8.1 (m, 8H ), 6.91(d,lH) 6.53 (t, IH ), 4.72 ( m, IH),
3.38 (m, 4H), 3.2 - 4.0 (m, 6H), 2.61(m, 2H), 1.99 (m,4H).
(S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] — 4 —
(2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide.
lU NMR (CDCI3, 8) :7.75 (d,2H), 7.46 (m,lH), 7.1 - 7.3 (m, 3H), 6.95 (d,lH), 6.44 (t, IH),
4.70(m, IH), 3.3 - 4.0 (m,4H ), 3.41(m, 4H) 3.24 (dd, 2H), 2.55 (t, 2H), 2.45 (d,2H),
2.01(m,4H), 1.81 (pent,lH), 0.83 (d, 6H).
(S) -N-][3-(3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-
(2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide.
lH NMR (CDCI3, 8) :7.76 (d,2H), 7.2 7.5(m, 4H), 6.95 (d,lH), 6.33 (t, IH), 4.69(m, IH),
3.88(t,lH), 3.71(t,lH), 3.6 - 3.7 (m,2H ), 3.45(m, 4H) 3.23 (dd, 2H), 2.56 (t, 2H), 1.94 (m,4H),
1.26(s,9H).
(S^J - N-[[3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4 —
(4 - acetamidophenyl) -4- oxobutanamide.
'H NMR (CDCU, 8) : 7.2 - 7.8 (m, 7H), 6.85 (d,lH), 6.47 (t, IH), 4.67(m, IH), 3.81(t,lH), 3.3 -
3.7 (m,3H ), 3.46(m, 4H) 3.16 (m, 2H), 2.3 - 2.9 (m,6H), 2.06(s,3H).
(Sp -N-[]3-(3-fluoro -4- pyrrolidinylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4-
oxo - 4 -phenylbut - 2- enamide.
'HNMR (CDCI3, 8) :7.8 - 7.9 (m,3H), 7.0 - 7.6 (m, 5H), 6.93 (d,lH), 6.75 (m,lH), 4.76(m, IH),
4.02(t,lH), 3.74 (m, 3H), 3.30 (m, 4H), 1.95 (m,4H).
(S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-
4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
!HNMR (CDCI3, 8) :7.78 (d,2H), 7.33 (dd,lH),6.99 (d,lH), 6.83 (t,lH), 6.81 (d, 1H),6.38 (t, IH)
4.69(m, IH), 3.86 (t,lH), 3.79 (s,3H), 3.5 - 3.8 (m,3H ), 3.41(m, 4H) 3.20 (m, 6H), 2.73(m,4H)
2.53 (t, 2H).
(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-
4 - (2,4 - dimethylphenyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) :7.55 (d,lH), 7.33 (dd,lH), 6.96 (m,3H), 6.81(t,lH), 6.22 (t, IH), 4.69(m,
IH), 3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.17(m, 6H) 2.73 (t, 2H), 2.45 (d,2H),2.51 (t,2H), 2.34(s,3H),
2.27 (s,3H).
(Si)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-
4 - oxo -4-(2- thienyl)butanamide.
!H NMR (CDCI3, 8) :7.63 (d,lH), 7.55 (d,lH), 7.33 (dd, IH), 7.05 (dd,2H), 6.85(t, IH), 6.31
(t,lH), 4.69(m, lH),3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.23(m, 6H) 2.73 (m, 4H), 2.55 (t, 2H).
39

(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - J - oxazolidinyl] methyl] -4-(4- acetamidophenyl) -4- oxobutanamide.
'HNMR ( DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.73(d, 2H), 7.59 (d, 2H), 7.38 ( dd, IH), 7.08(dd,lH), 6.99 (t, IH), 4.65 (m, IH), 3.95(t,lH),3.62(dd,lH), 3.08(m, 6H), 2.66 (m, 4H), 1.97 (s,3H).
(S) - N -[[ 3 - (3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] - 4 -oxo - 4 - (4 - thiomethylphenyl)butanamide.
•HNMR (CDC13,8) : 7.70 (d, 2H), 7.32 (dd,lH),7.14 (d, 2H,), 6.99(dd,lH), 6.82(t,lH), 6.33 (t, IH ), 4.68 ( m, IH), 3.86 (t, IH), 3.4 - 3.8 (m, 3H), 3.20(dt, 2H ), 2.90(t,4H) 2.53(t, 2H), 2.44(s,3H), 1.67 (m,4H), 1.5 (m,2H).
(S) -N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl] -4-(naphthyl) -4- oxobutanamide.
'H - NMR ( CDCI3) : 8.36 (s, IH ), 7.7 - 7.9 (m, 4H, ), 7.4 - 7.6 (m, 2H ), 7.32 (dd,lH), 6.99(d,lH), 6.78(t,lH), 6.43 (t, IH), 4.70 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.39(dt,2H), 2.86(t,4H), 2.61(t, 2H), 2.10(m,4H),1.50 (m,2H).
S) -N-[[ 3- (3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide.
lUNMR (CDCI3,8) : 7.75 (d, 2H), 7.37 (d,2H),7.31 (dd, IH, ), 7.00(dd,lH), 6.84(t,lH), 6.37 (t, IH ), 4.68 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.25(dt, 2H ), 2.91(t,4H) 2.54(t, 2H), 2.23(m,4H), 1.5 (m,2H), 1.26(s,9H).
(S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4-oxo -4-(4- thiomethylphenyl)butanamide.
'HNMR (CDCI3, 8) : 8.08 (d, 2H ), 7.77 (dd, IH, ), 7.63(d,2H), 7.2 - 7.5 (m, 4H ), 7.12 (d,2H), 6.41 (t, IH ), 4.81 ( m, IH), 3.98 (t, IH), 3.7 - 3.9 (m, 2H), 3.54(dt,lH), 3.22(qdd,2H), 2.54(dd, 2H), 2.36(s,3H).
(S) -N-[] 3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5 - oxazolidiny] methyl] -4-(2-naphthyl) -4- oxobutanamide.
'HNMR (CDCI3, 8) : 8.35( s,lH), 8.08 (d, IH ), 7.6 - 7.8(tn,5H), 7.2 - 7.6 (m, 7H ), 6.41 (t, IH ), 4.82 ( m, IH), 3.8 - 4.0 (m, 3H), 3.3 - 3.7(m,3H), 2.64(dd, 2H).
(S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4 - (2',2' - dimethyl- 4 - ethylphenyl) -4- oxobutanamide.
*H NMR (CDCI3, 8) : 8.08 (d, IH ), 7.80 (dd, IH, ), 7.70(d,2H), 7.57(t, IH), 7.2 - 7.5 (m, 4H ), 7.08 (d,2H), 6.41 ( t, IH ), 4.80 ( m, IH), 3.7 - 4.0 (m, 3H), 3.55(dt,lH), 3.1 - 3.4(m,2H), 2.54(dd, 2H), 2.37(d,2H), 1.72(pent,lH), 0.76(d,6H).
40

(S)-N-[[3-(3-Jluoro-4- henzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide.
JHNMR(CDC13, 5) :7.2 - 8.0 (m,13H), 6.95 (d,lH), 6.65 (m,lH), 4.89(m, IH), 4.18(t,lH), 3.7-4.0 (m, 3H).
(S) -N-[[3-(3-Jluoro-4-benztriazolylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 -(4- acetamidophenyl) -4- oxobutanamide.
!HNMR (DMSOde, 8) : 10.16 (s, IH), 8.29(t, IH), 8.12 (d, IH), 7.79 (m, 4H), 7.58 ( d, 2H), 7.4 - 7.5 (m, 4H), 4.74 (m, IH), 4.13(t,lH),3.08(dd,lH), 3.10 (t, 2H), 1.97 (s, 3H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide.
lH NMR (CDCI3,8) : 7.76 (d, 2H), 7.53 (dd, 1H),7.39 (d, 2H +1H, ), 7.02(d,lH), 6.29 (t, IH ), 4.71 ( m, IH), 3.89 (t, IH), 3.79(t,lH), 3.5 - 3.7 (m, 2H), 3.38(m, 4H ), 3.24 (dd,2H), 2.92(m,4H) 2.54(t, 2H), 1.26(s,9H).
(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide.
JH NMR (CDCU, 8) :7.8 - 7.9 (m,3H), 7.3 - 7.7 (m, 5H), 6.8 -7.0 (m,3H), 4.81(m, IH), 4.05(m,lH), 3.75 (m, 3H), 3.49 (m, 4H), 3.10 (m,4H).
(S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(fi- naphthyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) : 8.35 (s, IH), 7.7-8.0 (m, 4H), 7.3-7.7 (m, 5H), 7.01 (m, IH), 6.48 (m, IH), 4.74 (m, IH), 3.80 (m, 3H), 3.60 (m, IH), 3.37 (m, 6H), 2.93 (m, 4H), 2.60 (m, 2H) (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4- (4- chlorophenyl) -4-oxobutanamide.
!H NMR (CDCI3, 8) : 7.74 (d, 2H), 7.54 (d, IH), 7.34 (d, 2H+1H), 6.98 (d, IH), 6.35 (t, IH), 4.78 (m, IH), 3.88 (t, IH), 3.5-3.8 (m, 3H), 3.38 (m, 4H), 3.22 (dd, 2H), 2.93 (m, 4H), 2.54 (t, 2H).
(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4 - (2,4 - dimethyl- 4 ethylphenyl) -4- oxobutanamide.
lH NMR (CDCI3, 8) : 7.95 (m, IH), 7.74 (d, 2H+1H), 7.77 (d, 2H), 7.07 (d, IH), 6.38 (t, IH), 4.76 (m, IH), 3.91 (t,lH), 3.4-3.8 (m, 3H), 3.58 (m,4H), 3.25 (dd, 2H), 3.1 (m, 4H), 2.54 (t, 2H), 2.46 (d, 2H), 1.80 (pent, IH), 0.85 (s, 3H), 0.82 (s, 3H). Microbiology: Pharmacological testing
The compound of formula (I) of the present invention displayed antimycobacterial activity when tested by in vitro growth inhibition assay and agar incorporation methods. The minimum inhibitory concentrations (jag/ml) obtained for representative compounds of formula (I)
41

against M. tuberculosis including sensitive and resistant strains are summarized in Table-I. The MIC value of a representative preferred Compound No. 30 of formula I against different species of mycobacteria is summarized in Table-II. in vitro Growth Inhibition assay
The ability of the compounds 1-78 of formula (I) of this invention to inhibit the growth of Mycobacterium species was determined by the BACTEC 460 TB system. The reference strain M tuberculosis H37Rv ATCC 27294 was grown in Middlebrook 7H9 broth containing 10% ADC
supplement at 37°C on a rotay shaker at 150 rpm for grown for 7days. The turbidity of the culture was adjusted to 1.0 Mc farland. The BACTEC 7H12B medium vials were seeded with 0.1ml of the 1.0 Mc farland adjusted M. tuberculosis culture. In the control vials 0.1ml of the culture was added after lOOfold dilution of the initial inoculum. Stock solution of lmg/ml of each compound was prepared in DMSO in separate sterile tubes. The compounds were further diluted to concentration of 25 ^g/100 ul, 0.1ml was than added to the 7H12B vial containing mycobacterial culture so that final concentration of the compound 6.25 u.g/ml. The cap in all the vials were cleaned with isopropanyl alcohol and kept in racks. The vials were then incubated at 37°C without shaking. Test vials was read daily on the BACTEC system till the GI of the control vial reached > 30.Once the GI in the control reached 30 AGI (GI = GI (n> - GI („.i) ) was determined for all test and control vials. If AGI of test vial is less than that of the control vial the culture was sensitive to the test compound. in vitro Agar Dilution assay
MIC of compound of formula (I) of this invention against strains of Mycobacterium were determined by a reference agar dilution method as per the NCCLS- M24-T2. recommendations. The compounds were dissolved in DMSO and diluted twofold to obtain ten serial dilutions of each compound. Appropriate volume of compounds were incorporated into duplicate plates of Middlebrook7H10 agar medium supplemented with 10% Middlebrook supplement oleic acid-albumin-dextrose (OADC) enrichment at concentration of 0.03u,g/ml to 16|j,g/ml. Test organisms (mycobacterium strains) were grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement. After 7 days of incubation at 37°C the broths were adjusted to the turbidity of 1.0 McFarland standard; the organism were further diluted 10 fold in sterile water containing 0.10% Tween-80. The resulting mycobacterial suspensions were spotted (3-5jxl/spot) onto drug supplemented 7H10 media plates. The plates were sealed and incubated at 37°Cfor 3-4 weeks in upright position. The MIC was recorded as the lowest dilution of the drug that completely inhibited the growth of test organisms. Test isolates included 10 clinical isolates that were generally susceptible to common tubercular agents and 10 strains that were resistant to one or more standard anti tubercular drugs. Appropriate reference strains and control drug was included in each batch of test.
42

in vivo studies:
The efficacy of the compound of formula (I) of this invention was also evaluated in murine model of pulmonary tuberculosis. Mycobacterium tuberculosis cultures grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement at 37°C for 7 days on a rotary shaker. For, animal inoculation liquid cultures were declumped by brief sonication and were diluted appropriately in 7H9 broth to obtain a concentration of lxl07CFU's/ 0.2ml. Four-week-old male outbred Swiss albino mice housed in a pathogen free, biosafety level 3 environment within micro isolator cages were used throughout the study. Infections were produced by intravenous inoculation into caudal tail vein of 0.2ml of declumped M. tuberculosis suspension. Following infection, mice were randomly distributed in different groups of six each.
Treatment for initial study was started one day after infection. For, treatment Compound No. 30 of formula I was dissolved in 10% PEG. Isoniazid was dissolved in sterile water. The drugs were prepared each morning prior to administration. Therapy was given 5 days per week for four weeks. All the agents were administered by gavage and were dosed at 50,25,12.5mg / kg of body weight. Control group of infected but untreated mice were killed at the initiation of therapy (early control) or at the end of the treatment period (late control). Mice were sacrificed by cervical dislocation 3-5 days after the administration of the last dose of drug. The spleens and right lung were removed aseptically and homogenized in tissue homogeniser. At least 4 serial tenfold dilution of the homogenate was plated onto selective Middlebrook 7H11 agar plates in duplicate. The colony counts were recorded after incubation at 37°C for 4 weeks. The viable cell counts were converted to Logio values. A compound showing 2 Log reduction in viable counts compared to the controls was considered significant.
The in vivo data for a representative compound of formula (I) is given in Table-II.
Acute toxicity of Compound No. 30 of Chart-I was estimated in mice and the LDo was found to be >1000 mg/kg P. O.
43

Table-I: in vitro activity of compounds 1 to 58 of formula (I),

Compound No. Growth inhibition of
M.tuberculosis
27294 MIC (fig/ml) against

M.tuberculosis 27294 Clinical isolates

Sensitive Resistant
1 + 16 4-16 >16
2 + 8 8 8
8 + 2 .5-2 2-4
13 + 2 2 2-4
14 + 0.25 0.25-0.5 4->16
15 + >16 >16 >16
16 + 0.5 0.5 0.5(>16)
17 + 0.5 1.0 0.5-1.0
18 + 4- 1-4 8->16
19 + 2 1-2 2
20 + 1 1-2 2-4
21 + 0.5 0.5-2 0.5(>16)
25 + 4 4-16 4->16
27 + >16 >16 >16
28 + 0.5 1-2 2-8
30 + 0.5 0.5 0.5-2
31 + 1 1-2 1-4
32 + 0.25 0.25-0.5 4-(>16)
33 + 0.5 1 0.5-2
34 + >16 >16 >16
35 + 4 2-4 4-8
36 + 4 4-8 4-8
44

Table-I Contd....

39 + 2 2-4 2-8
40 + 1 1-2 1-2
43 + 1 0.5-1.0 1-2
44 + 1 0.5-2 1-4
45 . + 2.0 2-4 2-4
46 + 2 2-4 2-8
47 + 1 1-2 2-4
48 + 2 2-4 2-8
49 + 4 4-16 4-16
50 + 2 2-4 2-4
51 + 8 8->16 8->16
52 + 2 2 4->16
53 + >16 >16 >16
54 + 8 8-16 >16
55 + >16 >16 >16
56 + >16 >16 >16
57 + 16 16->16 >16
58 + 8 8-> 16 8-> 16
Isoniazid + 0.25 0.12- .25 8 - >16
Linezolid + 0.5 0.25-0.5 1.0-2.0
Table-II MIC values of compound of formula (I) against different species ofMycobacteria

Sr.
No. Compound No. MIC (ug/ml)

M. tuberculosis M.avium-
intracellular
complex M.fortuitum M.kansai

Sensitive Resistant

1 Compound 30 of formula I 0.50 0.50-2.0 8.0->16.0 >16.0 8.0
2 Isoniazid 0.25 4.0-> 16.0 8.0->16.0 >16.0 >16.0
45

Table-m in vivo activity of Compound of formula (I) against M. tuberculosis ATCC 27294" infection
in Swiss albino mice

Sr. No. Drug& Dose b (mg/kgday" ') or group Mean Logio No. of CFU Mean Logio No. of reductionc

Lung Spleen Lung Spleen
1 Compound 30 of Chart-I
50mg/kg 25mg/kg 12.5mg/kg 2.12 2.21 4.34 2.09 2.13 4.30 2.40 2.30 0.20 2.53 2.49 0.26
2 Isoniazid
50mg/kg 25mg/kg 12.5mg/kg 2.03 2.11 2.95 1.92 2.11 2.94 2.49 2.41 1.57 2.70 2.51 1.68
3 Infected early control 4.52 4.62
4 Infected late control 6.57 6.37
a- inoculation of logio:- 7.00 Mycobacteria.
b- mice were dosed 5 day/week for 4 weeks. From day 1 -28.
c- difference in mean logio number CFU from that of early controls.
The compound of formula I of this invention may be administrated to a subject such as a human being or an animal in need of such an administration through any route appropriate to the condition to be treatede. Suitable routes of administration include oral, rectal, nasal, topical (both buccal and sublingual), vaginal and parenteral (including subcutaneous, intramuscular, intradermal, intrathecal and epidural).
Pharmaceutical compositions of compound of formula I can be prepared in adjunction with inert pharmaceutically acceptable carriers, which can either be solid or liquid.
Solid form preparations include powders, tablets, dispersible granules, capsules, cachets, suppositories and ointments. The solid carriers can be one or more substances which may act also as diluents, flavouring agents, solubilisers, lubricants, suspending agents, binders or tablet disintegrating agents. It can also be finely divided solid which is in admixture with finely divided active compound. Suitable solid carriers are lactose, pectin, dicalcium phosphate, microcrystalline cellulose, sucrose, kaolin, dextrin, gelatin, starch, tragacanth, low melting wax, coca butter and the like.
Liquid preparations include solutions, suspensions and emulsions, e.g. solutions of compound of formula I in water or water-propylene glycol mixture for parenteral injection. Liquid preparations can also be formulated along with non-ionic surfactants and edible oils such as corn, peanut and sesame oils. Aqueous solutions for oral use can be prepared by dissolving the active component in water and adding suitable colorants, flavours stabilizing and thickening
46

agents, as required. Aqueous suspension for oral use can be made by dispersing the finely divided active component in water with a viscous material, e.g. natural or synthetic gums, resins, methyl cellulose, sodium carboxymethyl cellulose and othe known suspending agents. The adjuvants may also include preserving agents and anti-oxidants.
Compositions for topical application may take the form of liquids or gels, containing a therapeutically effective concentration of compound of formula I admixed with a dermatologically acceptable carrier.
The pharmaceutical preparations may be in unit dosage form. In such form, the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage can be in the form of tablets, capsules, powdersin vials or ampoules, ointments, gels, creams or any other form. The quantity or concentration of the active compound in such unit dose preparations may be varied or adjusted according to the particular application and potency of the active ingredient.
47

A compound of formula (I) and its pharmaceutical^ acceptable salts

wherein,
A is either hydrogen or fluorine,
B is either hydrogen or fluorine,
A and B together is hydrogen and fluorine,
Ri is a group of formula,

wherein,
Q is either an alkyl group of two carbon atoms, an alkene group of two carbon atoms or
an alkyne group of two carbon atoms
Y is oxygen, sulfur or an amino function of formula NR3
wherein,
R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be
straight or branched; cycloalkyl of 3-7 carbon atoms; CHO, -COOH, -COOR,; COCR,;
CN; aryl or heteroaryl
wherein,
Rt is an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of
3-6 carbon atoms.
Ar is a substituted phenyl ring or a substituted pyridine ring of formula

—O-R3
or Ar is a five membered ring of formula
48

or Ar is a fused bicyclic phenyl or pyridine ring of formula

wherein,
M is either CH or N
Z is CH, NH, O, or S,
X is a group selected from OR,, NR4R5, N02, SR,, SOOR,, SOONR4R5, F, CI, Br or I,
wherein R4 is as defined hereinbefore, and
and R3 is as defined hereinbefore
R5 is hydrogen or R4
R2 is selected from the groups shown below, and the corresponding N-oxides thereof.

A compound according to Claim 1 wherein in said compound of formula I Aryl is phenyl substituted with (0) or (1) of F, CI, "OCH3, "OH, "NH2, CrC4 alkyl, 0-C(0)-OCH3," N02or"CN.
49

3. A compound according to Claim 1 wherein said compound of formula I is selected from the group consisting of:
1) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl
] methyl ] - 4 - oxo - 4 - phenylbutanamide.
2) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
3) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
4) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide.
5) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
6) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
7) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide.
8) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
9) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
10) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
11) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide.
12) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide.
13)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
14) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide.
15) (S) - N -[ [ 3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide.
16) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl 1 methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide.
17) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
50

18) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
19) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl]-4-oxo-4-(2-thienyl)butanamide.
20) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
21)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide.
22) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
23) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
24) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
25) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
26) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) — 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
27) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
28) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide.
29) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide.
30) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide.
31)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (2 - thienyl)butanamide - N - oxide.
32) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide.
33) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N -oxide.
34) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
51

35) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4- oxobutanamide.
36) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4- oxobutanamide.
37) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4- oxobutanamide.
38) (S) - N -[ [ 3 - (3 - fluoro - 4 - benztriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
39) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
40) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
41) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4 - oxobutanamide.
42) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
43) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
44) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide.
45) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
46) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
47) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide.
48) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide.
49) (S) - N .-[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
50) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
51) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
52) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide.
52

53) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
54) (S) -N-[[3-(3- fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
55) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
56) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -■ ( 4 - thiomethylphenyl )butanamide.
57) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2 - naplrthyl) - 4 - oxobutanamide.
58) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide.
59) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
60) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
61)(S)-N-[[3-(3- fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
62) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
63) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
64) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide.
65) (S) - N -[ [ 3 - ( 5 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
66) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (4 - thiomethylphenyl)butanamide.
67) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
68) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
69) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide.
70) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
53

71) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
72) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
73) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
74) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
75) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
76) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) --2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2 - naphthyl) - 4 - oxobutanamide.
77) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - '2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
78) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -
oxazolidinyl ] methyl ] - 4 - (2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide.
- '
4. A compound as claimed in claim 3 wherein said compound of formula I is selected from the group of N-oxide of the said compounds 1 to 78.
5. A pharmaceutical composition comprising a) atleast one of I) any compound of claims 1 to 4 and II) its pharmaceutically acceptable salts and b) a pharmaceutically acceptable carrier.
6. A pharmaceutical composition according to claim 5 comprising a solid or liquid preparation.
7. A pharmaceutical composition as claimed in anyone of claims 5 to 6 for oral or parenteral administration.
8. A method of preparation of the compound of formula I and/or its pharmaceutically acceptable salts comprising:
coupling of the amino fragment of compound of formula II
5^

(II)

with a carboxylic acid of formula III in the presence of an acid activating group or a dehydrating agent in a suitable solvent.

(Ill)

wherein R2 has the same meaning as given in claim 1.
9. A method as claimed in claim 8 wherein the compound of formula II is preferably selected
from (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 -
oxazolidinyl] methyl amine, (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 -
oxo - 5 - oxazolidinyl] methyl amine,(S) - N -[3 - ( 3 - fluoro - 4 -
benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3
- (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, S) - N -[3 - (3 - fluoro - A - benzotriazolylphenyl) - 2 - oxo - 5 -oxazolidinyl] methyl amine, and (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine.
10. A method as claimed in anyone of claims 8 or 9 wherein the compound of formula III is
selected from 4-(2-Naphthyl)-4-oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic acid, 4-oxo-4-(2' methy lpropyl)phenylbutanoic acid, 4-Oxo-4-(2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 -
5S

oxobutanoic acid,4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 -
methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid,
. 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -difluorophenyl) - 4 -
oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 -
oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 -
phenyl - but - 2 - ynoic acid.
11. A compound of formula I, its pharmaceutically acceptable salts and pharmaceutical compositions obtained thereof substantially as herein described and illustrated.
Dated this 5th day of March 2005
Dr. Sanchita Ganguli
Of S. MAJUMDAR & CO.
Applicants' Agent
5t
F0RM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. - OXAZOLIDINONE DERIVATIVES, PROCESS FOR THEIR
PREPARATION AND THEIR USE AS ANTIMYCOBACTERIAL AGENTS
2. Applicants)
(a) NAME : LUPIN LIMITED
(b) NATIONALITY : An Indian Company
(c) ADDRESS : 159, C.S.T. Road, Kalina, Santacruz (East),
Mumbai - 400 098, Maharashtra, India
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed

FIELD OF THE INVENTION
The present invention relates to novel compounds belonging to the class of oxazolidinones useful in the treatment of acid fast organisms such as Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium spp. The present invention further relates to methods for preparation of the novel compounds and to pharmaceutical compositions containing the novel compounds useful in the treatment of tuberculosis. BACKGROUND OF THE INVENTION
Tuberculosis (TB), an infectious disease caused by the bacterium Mycobacterium tuberculosis is transmitted mainly through air, affecting most often the lungs. When persons with pulmonary TB cough they produce tiny droplet nuclei containing M. tuberculosis, which remain suspended in air for a prolonged period of time. A person who breathes the air containing the aforesaid droplet nuclei containing M. tuberculosis can become infected with TB.
TB, one of the three major infectious diseases in the priority list of the World Health Organization's (WHO) agenda kills about two million people around the world every year. About six million new cases are reported every year and nearly 20% of adult deaths and 6% of infant deaths are attributable to the disease (C. Dye et. al., J. Am. Med. Ass., 1999, 282, 677-686). About a billion people are expected to be affected by TB by the year 2020, with 35 million likely to succumb to the disease (WHO Fact Sheet No. 104, Global Alliance for TB Drug Development- Executive Summary of the Scientific Blueprint for TB Development : http://www.who.int/inf-fs/en/factl04.html).
With the emergence of the AIDS epidemic and the increase in cases of HIV coupled with TB as well as the continued resistance of M. tuberculosis to isoniazid and rifampicin, the two most powerful anti-tubercular drugs available today there is an urgent need for new anti-tubercular drugs to combat the killer disease (S. H. E. Kaufmann et. al., Trends Microbiol., 1993, 1,2-5 ; B. R. Bloom et. al., N. Engl. J. Med., 1998, 338, 677-678).
Although, many new compounds are becoming available for fighting a number of infectious diseases, the number of such compounds having antimycobacterial activity are few. This could partly be due to the complexity of research involved and partly due to business considerations (B. N. Roy et. al., J. Ind. Chem. Soc, April 2002, 79, 320-335 and references cited therein).
However, renewed thrust in research in the last decade has resulted in development of new antimycobacterial compounds,
a) differing widely in structures,
b) having different mode/mechanism of action,
c) possessing favourable pharmacokinetic properties,
d) which are safe and have low incidence of side-effects, and
e) which provide a cost-effective dosage regimen.
2

Among the aforesaid new compounds, the oxazolidinones first developed during the mid-1980s (W. A. Gregory et. al., J. Med. Chem., 1989, 32,1673-1681 and 1990,33,2569-2578 ; C-H Park et. al., J. Med. Chem., 1992, 35, 1156-1165) are a unique class in themselves. The in vivo results for some of the oxazolidinones show that they are active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, including resistant strains such as methicillin-resistant Staphylococcus aureus [MRSA], methicillin-resistant Streptococcus epidermidis [MRSE], penicillin-resistant Streptococcus pneumoniae [PRSP], vancomycin-resistant enterococci [VRE], etc. (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999,9 (5), 625-633 and the references contained therein).
The oxazolidinones inhibit bacterial protein synthesis at a very early step in the initiation of complex formation involved in the process of translating mRNA into protein. The oxazolidinones, in general, are not cross-resistant with any known antibiotic because of this unique mechanism (D. C. Eustice et. al., Antimicrob. Agents Chemother., 1988, 32, 1218 and Biochem. Biophys. Res. Commun., 1988,150. 965).
A feature of the oxazolidinone molecule is that only those compounds, which are enantiomers with a (5S)-acetamidomethyl configuration in the left side of the molecule are known to exhibit antibacterial activity (W. A. Gregory et. al., J. Med. Chem., 1989, 32, 1673-1681). Another feature is that most of such antibacterial compounds invariably carry a (substituted) phenyl ring attached to the nitrogen atom of the oxazolidinone ring in the right side of the molecule (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999, 9 (5), 625-633 and the references contained therein).
The most promising compound among the N-phenyl oxazolidinones, which has been approved for human use is (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidin-yl]methyl]-acetamide), commonly known as linezolid (M. Barbachyn et. al., WO 995/07271). Linezolid possesses good in vitro and in vivo potency against most of the Gram-positive bacteria, including resistant strains {Drugs of the Future, 1996,21.(11), 1116-1123).
The left hand side i. e. position 5- and the right hand side i. e. position 3- respectively of
the oxazolidinone ring nucleus allows for many variations and has resulted in the discovery of a
large number of compounds having antimicrobial and antibacterial properties. Such
representative compounds, albeit not meant to be limiting are disclosed in the following prior art
references. These are:
i) US 4,942,183 (Gregory et. al.) and US 4,948,801 (Carlson et. al.) collectively disclose
certain 3-substituted phenyl- 5-aminomethyl oxazolidinones, possessing useful
antibacterial activity, ii) US 5,529,998 (Habich et. al.) discloses certain 3-benzoxazoyl- and benzothiazolyl-5-
acetyl amino methyl oxazolidinones, useful as antibacterial medicaments.
3

iii) US 5,565,571, US 5,654,428, US 5,756,732, US 5,801,246 and US 5,929,248 (Barbachyn et. al.) collectively disclose several substituted aryl and heteroaryl phenyloxazolidinones carrying an acetyl aminomethyl function at the 5-position, specifically oxazolidinones having an aryl or heteroaryl group at the para position of the 3-phenyl ring and additional substituents at the meta positions of the 3-phenyl ring, which are useful as antibacterials.
iv) US 5,652,238 (Brickner et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a hydroxyl acetyl piperazine moiety, active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, as well as anerobic organisms such as bacteroides and Clostridia species as well as acid-fast organisms such as Mycobacterium tuberculosis.
v) US 5,684,023 (Riedl et. al.) discloses certain 3- benzofuranyl- and benzothienyl oxazolidinones, carrying an azido, hydroxy or acetyl aminomethyl group at the 5-position, useful as antibacterial medicaments.
vi) US 5,688,792 (Barbachyn et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a (substituted)-morpholine. Such compounds are useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp.
vii) US 5,719,154 (Tucker et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the said substitution being a pyrimidinyl or pyradazinyl group. Such compounds are useful as antimicrobial agents.
viii) US 5,736,545 (Gadwood et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a five membered heterocycle ring, in particular an azolyl ring. Such compounds are useful in the treatment of microbial infections.
ix) US 5,792,765 (Riedl. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-substituted phenyloxazolidinones, the substitution being a heterocyclic moiety, useful as antibacterial medicaments.
x) US 5,861,413 (Habich et. al.) discloses certain 2-oxo and 2-thio-l,2-dihydroxyqoinolinyl-1-oxazolidinones, useful as antibacterial medicaments.
xi) US 5,880,118 (Barbachyn et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a
4

substituted thiomorholine moiety i. e. oxazine and thiazine derivatives, useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp.
xii) US 5,910,504 and US 6,124,334 (Hutchinson et. al.) collectively disclose certain substituted 5-acetyl aminomethyl-3- phenyloxazolidinones substituted at the para position of the 3-phenyl ring with a heteroaromatic moiety, which is five membered having one to four nitrogen atoms or alternatively, a benzoannulated five-membered heteroaromatic ring having one to four nitrogen atoms, useful as antibacterials.
xiii) US 6,069,160 (Stolle et. al.) discloses certain substituted 5-acetyl aminomethyl-3-benzocyclopentaneoxazolidinones, containing an heteroatom, useful as antibacterial medicaments.
xiv) US 6,227,868 Bl and US 6,410,728 (Sciotti et. al.) collectively disclose certain 5-acetyl aminomethyl-3-phenyloxazolidinones carrying an acetylenic moiety on the 3-phenyl ring, useful for treating bacterial infections, psoriasis, arthritis and toxicity due to chemotherapy.
xv) WO 93/23384 (Hutchinson et. al.) discloses certain substituted 5-acetyl aminomethyl-3 -phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, useful for treatment of microbial infections caused by staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium.
xvi) WO 97/10223 (Gadwood et. al.) discloses certain substituted 5-acetyl aminomethyl-3-aminoaryl oxazolidinone N-oxide compounds, which are exceedingly water soluble and useful in preparation of pharmaceutical compositions for combating a number of human and veterinary pathogens, staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium, Mycobacterium spp. and Mycoplasma spp.
xvii) WO 98/01446 and WO 98/01447 (Betts et. al.) collectively disclose certain substituted 5-acetyl aminomethyl3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a six-membered heteroaryl ring containing two or three ring nitrogen atoms as the only ring heteroatoms, useful as antibacterial agents.
xviii) WO 99/02525 (Thomasco et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted by a thiadiazolyl or oxadiazolyl moiety, useful as
5

antimicrobial agents, effective against a number of human and veterinary pathogens, including Gram-positive and Gram-negative aerobic bacteria.
xix) WO 99/37630 (Gordeev et. al.) discloses oxazolidinone combinatorial libraries, compositionscontaining the same and methods of preparation thereof involving solid phase synthesis, which provides the said compounds for high-throughput screening.
xx) W099/37641 (Bartel. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-bicyclene-substituted oxazolidinones, useful as antibacterial medicaments.
xxi) WO 01/09107 (Gordeev et. al.) discloses certain 3-heteroaryl-5-acetyl aminomethyl oxazolidinones, substituted by a thioacyl, aminocarbonyl, alkoxycarbonyl, aminothiocarbonyl, alkoxythiocarbonyl and alkylthiocarbonyl group, useful in treating or preventing an infectious disorder in humans or animals.
xxii) WO 01/42242 (Paget et. al.) discloses certain substituted 5-acetyl aminomethyl 3-substituted phenyloxazolidinones, the substitution being a bicyclic heterocyclic system, useful as antibacterial agents.
xxiii) WO 02/06278 (Mehta et. al) discloses certain substituted 3-phenyl oxazolidinones and to process for synthesis of the same, the said compounds useful as antibacterial agents, effective against a large number of human and veterinary pathogens, including Gram-positive bacteria and acid fast organisms such as Mycobacterium tuberculosis.
xxiv) WO 02/20515 (Madar et. al.) discloses heterocyclic phenyloxazolidinones, useful for treating bacterial infections. However, only a few of the disclosures described hereinbefore provide compounds that
can be used as antimycobacterials, while most of the others are silent about the antimycobacterial
activity of the disclosed compounds.
A need, therefore, exists for new compounds possessing potent antimycobacterial
properties for treatment of TB, which as mentioned hereinearlier is assuming alarming
proportions.
OBJECTS OF THE INVENTION
It is thus the basic object of the present invention to synthesize, identify and provide new
compounds belonging to the class of oxazolidinones, possessing potent antimycobacterial
properties especially for treatment of acid fast organisms such as Mycobacterium tuberculosis,
Mycobacterium avium-intracellular complex, M. fortuitum and M. kansai.
Another object is directed to providing antimycobacterial pharmaceutical composition
effective in inhibiting/treating the generation of mycobacterial conditions/cells including
Mycotacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M fortuitum and Mkansai.
6

Yet another object is directed to providing a method of treating/inhibiting mycobacterial cells/conditions involving the administrations of effective amount of the novel antimycobacterial compound and/or its salts /composition of the invention. SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention there is provided compound of formula (I) and its pharmaceutically acceptable salts thereof

wherein,
A, B = H, and/or F Ri is a group of formula

wherein,
Q is CH2-CH2, CH=CH, or C=C
Y is O,S or NR3
wherein,
R3 is Ci - C4 alkyl (straight, branched, unsaturated), cycloalkyl, COOH, COOR,, CHO, COCR4,
CN, aryl, heteroaryl
wherein,

R is an alkane of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon
atoms, and
Ar is an aromatic carbocycle represented by

7

wherein,
X is OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, Br, CI, F, or I,
M is-CHorN,and
Zis-CH,-NH,OorS
and wherein,
R3 and R4 are as described hereinbefore, and
R5 is H, or same as R4, and
R.2 is selected from the groups shown below, and the corressponding N-oxides thereof

Heteroaryl or Heterocycloalkyl wherein K is O, S, SO, S02, or CH2
According to another aspect of the invention there is provided a pharmaceutical
composition comprising:
i) atleast one of an antimycobacterially effective amounts of compound of formula I and
pharmaceutically acceptable salts there of; and ii) a pharmaceutically acceptable carrier.
According to yet another aspect of the present invention there is provided a method of inhibiting growth of mycobacterial cells such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M.kansai.,comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof.
8

According to yet another aspect of the present invention there is provided a method of treating mycobacterial conditions such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M kansai, comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof.
According to another aspect, there is provided a process for the manufacture of the compound of formula I or its pharmaceutically acceptable salts comprising : coupling the amino fragments of compound of formula II with the carboxylic acid fragment of formula III.
The above disclosed compound of formula I its pharmaceutically acceptable salts thereof are found to have antimycobacterial properties and the same in admixture with pharmaceutically active additives, an be administrated orally or paranterally for treatement of mycobacterial conditions especially TB. DETAILED DESCRIPTION OF THE INVENTION
In the pharmaceutically active compound of formula (I) of this invention,

the definition of the symbols and groups A, B, Rt and R2 are as follows :
A is either hydrogen or fluorine,
B is either hydrogen or fluorine,
A and B together is hydrogen and fluorine,
When A is hydrogen, B is fluorine and vice-versa.
R1 represents a group of formula,

Q is either an alkyl group of two carbon atoms (CH2-CH2), an alkene group of two to carbon atoms (CH=CH), or an alkyne group of two carbon atoms (C=C)
9

Y can either be oxygen, sulfur or an amino function of formula NR3, wherein
R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or
branched. Suitable alkyl groups are methyl, ethyl, n-propyl, n-butyl, iso-propyl, iso-butyl, tert-
butyl, ethylene, propylene, 1, butene, both the geometric isomers of 2-butene i. e.(cis)-2-butene
and (trans)-2-butene, and iso-butylene. or
R3 is a cycloalkyl group of 3-7 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl,
cyclohexyl and cycloheptyl, or
R3 is a carboxylic acid group (-COOH) or a carboxylic acid ester of formula-COOR4, wherein
R4 is H, an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6
carbon atoms.
R3 is further an aldehyde (-CHO), an acetyl group (-COCR4), wherein R4 is as mentioned
hereinbefore or R3 is a nitrile (CN), aryl or heteroaryl, wherein
Aryl is phenyl substituted with (0) or (1) of-F, -CI, -OCH3, -OH, -NH2, -CrC4 alkyl, -O-C(O)-
OCH3,-N02or-CN,and
Heteroaryl
or Ar is a five membered ring of formula
or Ar is a fused bicyclic phenyl or pyridine ring of formula
10
The group Ar is a substituted phenyl ring or a substituted pyridine ring of formula

wherein,
M is either CH or N; Z is -CH, -NH, O or S and R3 is as defined hereinbefore,
X is a group selected from OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, F, CI, Br or I, wherein
R4 is as defined hereinbefore, and
R5 is hydrogen or R4.
R2 is selected from the groups shown below, and the corresponding N-oxides thereof.

Heteroaryl or Heterocycloalkyl
wherein K is O, S, SO, S02, or CH2
The preferred novel compounds of formula (I) that form part of this invention, are as follows.
The following compounds 1 to 78( named as per IUPAC or CAS nomenclature) are preferred compounds of formula (I) of the invention.
1. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide.
2. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
3. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
4. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide.
5. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
11

6. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide.
7. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide.
8. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
9. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
10. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ]
- 4 - oxo - 4 - phenylbutanamide.
11. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methylphenyl) - 4- oxobutanamide.
12. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - (4 - methylphenyl) - 4- oxobutanamide.
13. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
14. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide.
15. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide.
16. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide.
17. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
18. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
19. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide.
20. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - (2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
21. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide.
22. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
23. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
12

24. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazohdinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
25. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazohdinyl methyl] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
26. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazohdinyl ] methyl
- 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide.
27. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
28. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl
- 4 - oxo - 4 -( 2 - thienyl)butanamide.
29. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide.
30. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide.
31. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide.
32. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide.
33. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N - oxide.
34. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
35. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methoxyphenyl) - 4- oxobutanamide.
36. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - chlorophenyl) - 4- oxobutanamide.
37. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2,4 - dimethylphenyl) - 4- oxobutanamide.
38. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benztriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
39. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
40. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
41. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
13

42. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
43. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide.
44. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide.
45. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
46. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
47. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide.
48. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide.
49. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
50. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
51. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
52. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 -( 2 - thienyl)butanamide.
53. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
54. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
55. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - phenylbut - 2- enamide.
56. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - oxo- 4 - ( 4 - thiomethylphenyl )butanamide.
57. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - (2 - naphthyl) - 4 - oxobutanamide.
58. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide.
59. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
14

60. (S) - N -[ [ 3 - (3 - fluoro—4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
61. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbut - 2- enamide.
62. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
63. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide.
64. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide.
65. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
66. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - (4 - thiomethylphenyl)butanamide.
67. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - ( 2 - naphthyl) - 4 - oxobutanamide.
68. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
69. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide.
70. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
71. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
72. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
73. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
74. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
75. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
76. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
77. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
15

78. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 — oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide.
The respective N-oxides of the group R2 of the compounds of formula I listed above also form a novel aspect of the present invention.
The pharmaceutically active compounds of formula (I), the corresponding N-oxides of the group R2 and pharmaceutically acceptable salts thereof of this invention can be prepared by methods known to one skilled in the art.
Typically, compounds of formula (I), can be prepared by coupling of the amino fragment of formula (II)

Scheme-!
General method for synthesis of compounds of formula (I)

In a typical experiment, the amine compound of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinbefore is dissolved in a 1:1 mixture of tertahydrofuran and water or a 1:1 mixture of methylene chloride and water. To the solution is added the carboxylic acid compound of formula (III), followed by addition of 1-hydroxybenztriazole (HOBt). The resulting mixture is cooled to a temperature of 0-5° C to which l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 1.1 Eq.) is added and gradually allowed to warm to room temperature and agitated at this temperature for 24 hours. At the end of
17

the reaction, a solution of saturated aqueous sodium bicarbonate is added and the organic phase separated from the aqueous phase. Evaporation of the solvent and chromatography of the residue over silica gel affords compound of formula (I), generally as white solids.
The N-oxides of the group R2 of compound of formula (I) thus obtained are preferably prepared by addition of m-chloro perbenzoic acid (m-CPBA) to a cooled solution of the compound of formula (I) in a chlorinated hydrocarbon solvent such as methylene chloride and ethylene chloride and thereafter agitating the reaction mixture at room temperature for 12-15 hours. Evaporation of the solvent under reduced pressure, followed by chromatography of the residue over silica gel affords the corresponding N-oxides in high purity.
The N-oxides thus prepared, while retaining most of the antimycobacterial activity of the corresponding deoxo compound exhibit exceedingly high water solubility over the deoxo analogue, thereby helping in manufacture of suitable iv formulations, which forms an important aspect of this invention.
The starting materials required for synthesis of compound of formula (I), thus involve the amine compound of formula II and the carboxylic acid compound of formula III.
The amine compound of formula II can be selected from i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, vi) (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, and viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 -
oxazolidinyl] methyl amine.
18

The carboxylic acid compound of formula III can be selected from 4-(2-Naphthyl)-4-
oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic
acid, 4-oxo-4-(2'methylpropyl)phenylbutanoic acid, 4-Oxo-4-
(2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 - oxobutanoic acid,4 - (2,4 -
dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4-
chlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid,
4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 - phenyl - but - 2 - ynoic acid.
20

Thus, the starting amines of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinearlier are prepared as per the method disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33, 2569-2578; C. Wang et. al., Tetrahedron, 1989, 45, 1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO 95/25106 and WO 97,21708. The method is essentially summarized in Scheme-II.

In a typical method, morpholine, thiomorpholine, piperidine, 4-benzyl piperazine, pyrrolidine, 1,2,4-triazine, 12,3-benzotriazine, benzyl amine, a heterocycloalkyl or a heteroaryl moiety etc., each one of which corresponds to the group R2 defined hereinbefore is reacted with 3,4-difluoro nitrobenzene in the presence of a base and a solvent to give the corresponding derivative in which the fluorine atom at 4-position is substituted by the group R2. The nitro group in the compound thus obtained is reduced to amino group, which is thereafter protected by a suitable protective group. Reaction of the N-protected compound thus obtained with (R)-glycidyl butyrate in the presence of a strong base like n-butyl lithium leads to formation of the 5-hydroxymethyl oxazolidinone ring. The hydroxy group in the compound thus obtained is converted to sulfonyl derivative, for e.g. a methanesulfonyloxy (mesyl) or a p-toluenesulfonyloxy (tosyl) derivative by reaction with methanesulfonyl chloride or p-toluenesulfonyl chloride respectively. Reaction of the respective mesyl or tosyl derivative with sodium azide gives the corresponding azide, which is converted to the amine compound of formula (II) by standard methods, for e.g. by reaction with a triaryl/trialkyl phosphine, followed by hydrolysis.
The starting carboxylic acid fragments of formula (III), wherein the group Ar has the same meaning as defined hereinearlier are prepared as per the method disclosed in Org. Reactions, 1949, 5, 229-289; Quart. Rev. Chem. Soc, 1954, 8, 355-379; Chem. Rev., 1955, 55, 229-281, and J. Am. Chem. Soc, 1947, 69, 1784-1786. The method is essentially summarized in Scheme-HI.
Scheme-Ill General method for synthesis ofalkane and alkene carboxylic acid s of formula (HI)

In a typical method, the aromatic compound Ar-H, wherein Ar is as defined hereinbefore is reacted with succinic anhydride in the presence of a Lewis acid, such as anhydrous aluminium chloride and in the presence of an anhydrous solvent and the mixture heated to 100° C to give the carboxylic acid derivatives of formula (HI), wherein Q is alkyl of 1-4 carbon atoms.
23

Similarly, compounds of formula (III), wherein Q is an alkene (CH=CH) are prepared by reaction of the aromatic compound Ar-H, wherein Ar is as defined hereinbefore with maleic anhydride under the same conditions mentioned hereinbefore.
Compounds of formula (III), wherein Q is an alkyne (C=C) are prepared by reaction of propiolic acid ester with an aldehyde of formula Ar-CHO in the presence of butyl lithium and in the presence of an aprotic solvent such as THF at -78° C to give the corresponding secondary alcohol, which is oxidized to the keto derivative using manganese dioxide as the oxidizing agent. Saponification gives the carboxylic acid derivative of formula (ID) [ US 4,929,741 (A. Fischili et. al.) ] The synthesis is summarized in Scheme-IV.

P = any protective group
The synthesis of compound of formula (I) of this invention and the synthesis of the respective starting material amines of formula (II) and the carboxylic acids of formula (III) are further described herein in detail.
SYNTHESIS OF THE STARTING AMINES OF FORMULA OD
The amines were prepared as per the chemistry summarized in the Scheme-H and as per the methods disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33,2569-2578; C. Wang et. al., Tetrahedron, 1989, 45,1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO
24

95/25106 and WO 97,21708. Commercially available raw materials and known techniques were utilized for the synthesis.
The optically pure amines as such were obtained by using optically active intermediates or resolution of racemic mixtures by a suitable reagent. The preferred enantiomer is (S), at the chiral centre on the oxazolidinone ring.
Example 1 General Method for Preparation of the Amines (II)
The oxazolidinone azides of general formula (8), given in Scheme-II (1.0 eq) were dissolved in dry THF (10 times by volume ) and treated with triphenyl phosphine (1.5 eq.) at room temp. The resulting solution was stirred for 6hrs at room temp. Water [2 eq. of (8)] was added and the solution heated for 6hrs at 55 - 60° C. The solvent was evaporated and the residue chromatographed on a column of silica gel (100 -200 mesh) and eluted initially with ethyl acetate and then with chloroform : methanol (4:1) to give the the amines (II) as white solids.
The following amines i) to viii) of formula I were prepared by this general method, viz.
i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, vi) (S) - N -[3 - (3 - fluoro — 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, and
viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 -
oxazolidinyl] methyl amine.
SYNTHESIS OF THE STARTING CARBOXYLIC ACIDS OF FORMULA (HP
Example 2 4-(2-Naphthyl)-4-oxobutanoic acid
Naphthalene (5.0gm, 0.039moles) and succinic anhydride (4.68gm, 0.0468 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (11.44g, 0.0858 moles) was added at
25

room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 25 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid. Subsequent column chromatography gave a buff coloured solid. Subsequent chromatography gave 3.7 gm (41%) the title compound, mp 173-174° C.
'H NMR (CDCI3, 5) : 8.40 (s,lH), 7.7 - 8.0 ( m, 4H), 7.4 - 7.6 (m,2H), 3.33 (t,2H), 2.77 (t,2H + 1H).
The filterate was concentrated to give 5.8 gm of a mixture of 4-(2-naphthyl)-4-oxobutanoic and 4-(l-naphthyl)-4-oxobutanoic acid.
Example 3 4- Oxo-4-(2- ThienylJbutanoicacid
Thiophene (5.0gm, 0.059moles) and succinic anhydride (7.13gm, 0.0713 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (17.43gm, 0.131 moles) was added at room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 30 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (50 ml). The solid was dried at room temp to give 9.8 gm (89%0 of the title compound, mp 103 - 107° C.
!H NMR (CDCI3, 8) : 7.69 (dd, 1H), 7.58 (dd, 1H), 7.07 (dd,lH), 3.9 (bs, 1H), 3.23 (t, 2H), 2.74 (t,2H).
Example 4 4- Oxo-4-(4-thiomethyl)phenylbutanoic acid
Thiophenol methyl ether (8.0gm, 0.0645moles) and succinic anhydride (7.75gm, 0.0774 moles) were taken up in dichloroethane (80 ml). Aluminium chloride (18.90gm, 0.1419 moles) was added at room temperature. The resulting mixture stirred for 0.5hr and then heated at 85° C for lhr. The reaction mixture was cooled to room temperature, diluted with 40 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (80 ml). The solid was dried at room temp to give 6.9 gm (48%) of the title compound, mp 151 -154° C. *H NMR (CDCI3, 5) : 7.82 (d,2H), 7.20 (d, 2H), 4.2 (bs, 1H), 3.21 (t, 2H), 2.73(t, 2H),2.45 (s,3H).
26

Example 5 4 - oxo -4- (2'methylpropyl)phenylbutanoic acid
2'methylpropylbenzene (5.0m, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles), were taken up in dichloroethane (50 ml). Aluminium chloride (10.90g, 0.0821 moles ) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 ml of a 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.7 gm (99%) of the title compound as a solid, mp 102 - 105° C.
!H - NMR (CDC13, 8) : 7.83 (d,2H), 7.17(d,2H), 3.24(t,2H), 2.74(t, 2H), 2.46 (d, 2H), 1.80 (pent., 1H).
Example 6 4 - Oxo - 4 - (2',2'dimethylethyl)phenylbutanoic acid
2',2'dimethylethylbenzene (5.0gm, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (10.90gm, 0.0821 moles) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 m of a 1:1 mixture of water Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.5 gm (97%) of the title compound as a solid, mp 103 — 107° C. !H-NMR (CDCI3,8) : 7.94(d,2H), 7.50 (d, 2H), 3.29 (t,2H), 2.82 (t,2H), 1.36 (s,9H).
Example 7 Using the appropriate aromatic compound (Ar-H) and succinic anhydride and following exactly the method described in Examples 2-6 the following carboxylic acids can be prepared, viz.
i) 4 -(4 -methylphenyl)- 4 - oxobutanoic acid,
ii) 4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid, iii) 4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid, iv) 4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, v) 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, vi) 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid, vii) 4 -{2- Naphthyl)- 4 - oxobutanoic acid, viii) 4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, ix) (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and x) 4 - oxo - 4 - phenyl - but - 2 - ynoic acid.
27

SYNTHESIS OF THE COMPOUNDS OF FORMULA (D
Example 7
Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - J -
oxazolidinyl ] methyl] — 4-(4- naphthyl) -4- oxobutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 dichloromethane-water mixture (10 ml). To this was added 4 -( 2 - naphthyl- 4 - oxobutanoic acid (0.154gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) the resulting mixture was cooled to 0° C. l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added the resulting mixture was allowed to warm to room temperature and then stirred for 24hr. Saturated aqueous sodium bicarbonate solution (2ml) was added to the reaction mixture, stirred for 15 min and then the organic layer separated and the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.22 gm, 64%) as a white solid. MS (M+l) = 506 m/z
*H NMR (CDC13, 5) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, 1H ), 7.01(dd,lH ), 6.74 (t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, 1H), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91 (m,4H), 2.60(t, 2H).
Example 8
Preparation of (S) -N-[[3- (3-fluoro-4-morpholinylphenyl) -2-oxo-5-
oxazolidinyl ] methyl] -4- oxo -4-(2- thienyl)butanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml) . To this was added 4 - oxo - 4 (2 - thienyl)butanoic acid (0.125gm, 0. 00068 moles) and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the resulting mixture was allowed to warm to room temp and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated sodium bicarbonate was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separatedand the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.175 gm, 56%) as a white solid
MS (M+1) = 462 m/z
28

lH NMR (CDC13, 8) : 7.63(d,lH ), 7.55 (dd,lH ), 7.35(dd,lH), 7.04(t, like dd, 2H), 6.83(t,lH), 6.30 (t,lH), 4.69(m,lH), 3.93 (t, 1H), 3.6- 3.8 (m, 3H),3.80 (m,4H), 3.61(dd, 2H), 3.21(dd,2H),2.97 (m,4H),2.55(t, 2H).
Example 9
Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -
oxazolidinyl ] methyl ] - 4 - [4 - ( V- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 -oxo - 5 -oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml). To this was added 4 - [ 4(2'-methylpropylphenyl)]- 4 - oxobutanoic acid (0.158gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated, and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.210gm, 60%) as a white solid.
MS(M=l) = 512m/z
'H NMR (CDC13, 8) : 7.73(d,2H ), 7.52 (dd,lH ), 7.28(m,lH ),7.15(d,2H ), 7.05 (d,lH), 6.39 (t,lH), 4.75(m,lH), 3.91 (m, 4H), 3.5- 3.9 (m, 4H), 3.28 (dd, 2H), 3.16 (m,4H),2.54 (t, 2H), 2.45 (d, 2H), 1.82 (pent., 1H), 2.60 (t, 2H).
Example 10
Preparation of(S) -N-[ [3 - (3 -fluoro -4- morpholinylphenyl) - 2 -oxo - J -
oxazolidinyl J methyl J -4- oxo - 4 -(4- thiomethyl) phenylbutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF -water mixture (20 ml). To this was added 4 - (4-methlythiophenyl) - 4 - oxobutanoic acid (0.152g, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) and the resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142g, 0.00074 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate was added to, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The
29

combined fractions were concentrated to give the title compound (0.270 gm, 79%) as a white solid.
MS (M+l) = 502 m/z
JH NMR (CDC13, 5) : 7.70(d,2H ), 7.37 (dd,lH ), 7.14(d,2H ), 7.00 (dd,lH), 6.79(t,lH), 6.38 (t,lH), 4.71(m,lH), 3.86(t,lH),3.5- 3.9 (m, 4H), 3.81 (m, 4H), 3.22 (dd, 2H), 2.96 (m,4H),2.53 (t, 2H), 2.45(s,3H).
Example 11
Preparation of:. (S) - N-[[3 - (3 -fluoro -4- morphottnylphenyl) — 2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) - 4 - oxobutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.100gm, 0.00034 moles) was taken up in 1:1 THF-water mixture (20 ml) . To this was added 4 - (4- chlorophenyl) - 4 - oxobutanoic acid(0.072g, 0.00034 moles and HOBt (0.046g, 0.00034 moles) .The resulting mixture was cooled to 0°C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.071gm, 0.00037 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated and 2 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with dichloromethane. The organic layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give (0.070gm, 42%) of the title compound as a white solid.
MS (M+l) = 490 m/z
JH NMR (CDCI3, 8) : 7.72(d,2H ),7.37 (dd,lH ),7.31(d,2H ), 6.98 (dd,lH),6.79 (t,lH), 6.28
(t,lH), 4.69(m,lH), 3.83 (t, 1H), 3.81 (m, 4H), 3.4- 3.m (m, 3H), 3.21 (dd, 2H), 2.97 (m,4H),2.54
(t,2H).
Example 12
Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -
oxazolidinyl ] methyl ] - 4 - ( 2 -naphthyl) - 4 - oxobutanamide - N - oxide.
To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -
2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (2 -naphthyl) - 4 - oxobutanamide (0.950gm, 0.0019
moles) in dichloromethane (150 ml) was added 60% m -CPBA (0.550g, 0.0032 moles) and the
resulting solution stirred at room temperature for 12hr. The solvent was evaporated under
reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The
column was eluted with ethyl acetate (200 ml), followed by a mixture of chloroform : methanol
30

(4:1,600 ml).Concentration the combined fractions gave the title N-oxide (0.891g, 82% ) as a
white solid.
!H NMR (CDCI3, 8) : 8.59(t,lH ), 8.36(s,lH),7.7-7.9 (m,5H), 7.2 -7.5 (m,2H),7.08 (dd,lH),
6.60(t,lH), 4.76(m,lH), 4.61(bt,2H), 3.5 - 4.3 (m, 9H), 3.42 (dd, 2H), 2.83 (bdd,2H), 2.61 (bt,
2H).
Example 13
Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide. To a cooled solution (0 - 5° C) of (S) - N -[[3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - oxo - 4 - (2 - thienyl)butanamide (0.850gm, 0.0017moles) in dichloromethane (120 ml) was added 60% m -CPBA (0.550g,0.0032 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The column was eluted with ethyl acetate (200ml) followed by a mixture of chloroform : methanol (4:1,600 ml).Concentration of the combined fractions gave the tile N-oxide (0.790g, 90%) as a white solid.
1HNMR( CDCI3,5) : 8.63(t,lH), 7.77(dd,lH), 7.65 (d, 1H), 7.56 (d, 1H), 7.09 (dd, 1H),7.04 (dd,lH), 6.45(t,lH), 4.68(m,lH), 4.65(bt,2H), 4.22 (dt,2H), 3.89(t,lH), 3.5 - 3.9 (m, 5H), 3.22 (dd, 2H), 3.00 (bd,2H), 2.54 (t, 2H).
Example 14 Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) -4- oxobutanamide -N- oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide, (1.150gm, 0.0023 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.725gm, 0.0040 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1,600 ml). Concentration of the combined fractions gave the title N-oxide (0.950g, 80%) as a white solid.
'HNMRtCDCk 8) : 8.61(t,lH ), 7.76(d,2H), 7.72 (dd, 1H), 7.34 (d, 2H), 7.10 (dd, 1H), 6.46(t,lH), 4.70(m,lH), 4.64(bt,2H), 4.16 (dt,2H), 3.94(t,lH), 3.5 - 3.9 (m, 5H), 3.24 (dd, 2H), 2.97 (bd,2H), 2.55 (t, 2H).
31

Example 15 Preparation of(S) -N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo -5-oxazolidinyl ] methyl] -4-/4-(2'- methyl - 4 -propylphenyl) -4 — oxobutanamide -N-
oxide.
To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - [4 - (2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide (1.05gm, 0.0020 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.600gm) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1 , 600 ml). Concentration of the combined fractions gave the title N-oxide (0.891gm, 82%) as a white solid.
JH NMR (CDC13, 5) : 8.62(t,lH ), 7.77(dd,lH), 7.75 (d, 2H), 7.14 (d, 2H), 7.12 (dd, 1H), 6.44(t,lH), 4.75(m,lH), 4.64(bt,2H), 4.20 (dt,2H), 3.95(t,lH), 3.91 (t,lH) 3.5-3.9 (m, 4H), 3.26 (dd, 2H), 2.99(bd,2H), 2.57 (t, 2H),2.44(d,2H), 0.83(d,6H).
Example 16 Preparation of (S)-N-ff3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4-
methylphenyl)-4-thiooxobutanamide
To a solution of (S)-n- of (S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4-methylphenyl)-4-oxo-butanamide (0.1 Ogm, 0.00021 moles) in dry THF (5ml) was added Lawessons Reagent (0.052gm, 0.000128 moles) and the resulting solution heated under reflux for 8 hr. The reaction mixture was cooled to room temperature and to this was added saturated aqueous sodium carbonate solution (3ml) and then extracted with ethyl acetate. The solvent was evaporated off and the residue chromatographed over silica gel and eluted with a mixture of ethyl acetate-hexane to give the title compound (0.023 gm, 23%) as a white solid, mp 149-151° C.
lH NMR (CDCI3,5) : 8.60 (m, 1H), 7.68 (d, 2H), 7.34 (dd, 1H), 7.14 (d, 2H), 6.96 (dd, 1H), 6.81 (t, 1H), 4.90 (m, 1H), 4.20-4.40 (m, 1H), 3.80-4.0 (m, 4H), 3.50 (m, 2H), 2.90-3.00 (m, 6H).
Example 17 Using the appropriate amine compound (II) and the carboxylic acid (HI) and following exactly the method described in Examples 7-16 the following carboxylic acids can be prepared, viz.
(S) - N-[ [ 3 - (3-fluoro — 4- morpholinylphenyl) -2- oxo — 5- oxazolidinyl J methyl] — 4-(4- methylphenyl) -4- oxobutanamide.
32

'H NMR (CDCI3, 5) : 7.78 (d, 2H ), 7.44 ( d, IH ), 7.22 ( d,2H ), 7.09 ( d, IH ), 6.88 ( t, IH ), 6.41(t, IH), 4.76 (m, IH ), 3.6 - 4.1 (m, 4H ), 3.86 ( m, 4H ), 3.31 ( dd, 2H ), 2.61 (t, 2H ), 2.40 (s.3H).
(S) -N-[[ 3-(3 -fluoro -4 - benzylpiperazinyl) phenyl] -2- oxo - 5 - oxazolidinyl] methy ] -4-oxo -4-phenylbutanamide.
lH -NMR (CDC13, 5) : 7-88 ( d,2H ), 7.61 (dd, IH), 7.38 ( m, 5H ), 7.2 - 7.4 (m, 5H), 6.88 (t, IH ), 6.55 (t, IH ), 4.77 ( m, IH), 3.94 (t, IH), 3.5 - 3.7 (m, 3H ), 3.71 ( s, 2H ), 3.34 (dd, 2H ), 3.12 (m, 4H),3.12 (m, 4H ), 2.61 (t, 2H ).
(S) - N-f]3 - ( 3 -fluoro - 4 - [methylbenzylamin]phenyl) - 2 - oxo -5 - oxazolidiny] methy ]-4-(4- methyl phenyl) -4- oxobutanamide.
*H NMR (CDCI3, 8) : 7.90 ( d, 2H ), 7.52 ( dd, IH ), 7.2 - 7.5 ( m, 8H ), 7.05 ( d, IH ), 6.84 (t, IH ), 6.50 (t, IH ), 4.75 (m, IH ), 4.48 (s, 2H ), 3.95 (t, IH), 3.6 - 4.1( m,3H ), 3.64 ( dd, 2H ), 2.71 (s,3H), 2.62 (t,2H).
(S)-N-[[3-(3-fluoro-4- benzotriazolylpheny)-2-oxo-5-oxazolidinyl]methy]-4-oxo - 4 -phenylbutanamide.
!H NMR ( CDCI3, 5) : 8.16 ( d,lH), 7.84 (d, 2H), 7.66 (t, IH), 7.2 -7.6 (m, 8H), 6.46 (t, IH ), 4.90 (m, IH), 3.98 (t,lH), 3.9 - 4.0 (m, 2H ), 3.65 (m, IH ), 3.39 (ddd, 2H ), 2.65 ( ddd, 2H). (S) -N-[[3-(3-fluoro-4- pyrrolidinylphen) -2-oxo-5- oxazolidinyl]methyl]-4-oxo - 4 -phenylbutanamide.
!H NMR (CDCI3, 8) : 7.90 (d,2H ), 7.52 (dd, IH ), 7.44 (d, 2H ), (dd, IH ), 7.04 (dd, IH), 6.65 (t, IH), 6.43 (t, IH), 4.74 (m,lh), 3.93 (t,lH), 3.77 (t,lH), 3.6 3,8 (m, 2H), 3.33 (m, 6H ), 2.63 (t, 3H), 1.94 (m,4H).
(S)-N-[[3-(3-fluoro-4- benzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methy]-4-(4- methlyphenyl) - 4- oxobutanamide.
!HNMR (CDCU, 8) : 8.16 (d, IH ), 7.3 - 7.9( m,7H), 7.78 (d,2H ), 7.21(d,lH), 6.54(t, IH), 4.89 ( m, IH), 3.8 -42 (m, 3H ), 3.4 - 3.7 (m, 3H ), 2.63 (dd, 2H ), 2.23 (s, 3H ). (S)-N-][3-(3 -fluoro - 4 - thiomorpholinylphenyl) -2 — oxo - 5 - oxazolidinyl] methyl] -4- oxo- 4 -phenylbutanamide.
!H NMR (CDCI3, 8) : 7.89 (d, 2H ), 7.39 - 7.60 ( m, 4H ), 7.11 (dd, IH ), 6.90 (t, IH), 6.39 ( t,lH ), 4.76 (m,lH ), 3.94 (t,lH ), 3.80 (t, IH ), 3.6 - 3.7 ( m, 2H ), 3.36 ( dd, 2H ), 3.28 ( m,4H), 2.80 ( m,4H ), 2.62 (t, 2H).
(S) — N-[[3 - (3 -fluoro - 4 - benzylpiperazinyl) phenyl] — 2 — oxo — 5 - oxazolidinyl] methyl]- 4-(4- methylphenyl) -4- oxobutanamide.
33

*H NMR (CDCI3, 5) : 7.81 ( d, 2H), 7.2 - 7.5 ( m, 8H ), 7.08 (dd, IH ), 6,89 (t, IH ), 6.39 (t, IH
), 4,78 ( m, IH ), 3.95( t, IH), 3.79 (t, IH), 3.6 - 3.7 (ni, 2H ), 3.61(s, 2H), 3.31 ( m,2H), 3.09
(m,4H), 2.65 (m,6H), 2.41 (s, 3H).
(S)-N-[[3-(3-fluoro-4- piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl]-4-
oxo - 4 - phenylbutanamide.
!H NMR (CDCI3, 8) : 7.90(d,2H ),7.60 (dd,lH ),7.45(d,2H ), 7.39 (dd,lH), 7.10 (dd,lH), 6.90
(t,lH), 6.55 (t,lH), 4.78(m,lH), 3.95 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.35 (m, 2H), 3.00
(m,4H0,2.63 (t, 2H), 1.9-1.6 (m,6H).
(S)-N-[[3- (3 -fluoro-4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4-(4
- methylphenyl) - 4- oxobutanamide.
JH NMR (CDCI3, 5) : 7.79(d,2H ),7.40 (dd,lH ),7.23(d,2H ), 7.09 (dd,lH), 6.91 (t,lH), 6.40
(t,lH), 4.77(m,lH), 3.98 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.30(t, 2H), 2.98 (m,4H), 2.62 (t,
2H),2.41(s,3H), 1.6-1.9 (m,6H).
(S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5- oxazolidinyl] methyl]- 4
-(4- methylphenyl) - 4- oxobutanamide.
'H NMR (CDCI3, 8) : 7.80(d,2H ),7.32 (dd,lH ),7.21(d,2H ), 7.01 (dd,lH), 6.60 (t,lH), 6.40
(t,lH), 4.75(m,lH),4.12(m,lH) 3.94 (t, IH), 3.75 (t, IH), 3.4- 3.6 (m, 2H), 3.34 (m, 6H), 2.61 (t,
2H),2.40(s,3H), 1.9(m,4H).
(S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4
-(4- methoxyphenyl) -4- oxobutanamide.
lU NMR (CDCI3, 8) : 7.79(d,2H ),7.36 (dd,lH ), 7.00 (dd,lH), 6.82 (d,2H), 6.80(t,lH), 6.38
(t,lH), 4.69(m,lH), 3.80 (s, 3H), 3.78 (m, 4H), 3.4- 4.0 (m, 4H), 3.20 (dt, 2H), 2.97 (m,4H),2.55
(dt,2H).
(S) -N-[[3-(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-
(2 -naphthyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, IH ), 7.01(dd,lH ), 6.74
(t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, IH), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91
(m,4H), 2.60(t, 2H).
((S) - N -[[ 3 - (3 -fluoro -4- morpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-
(2, 4-difluorophenyl) -4-oxobutanamide.
!H NMR (CDCI3, 8) : 7.73(ddd,2H ), 7.47 (dd,lH ), 7.01(dd,lH ),6.7 - 6.9(m,3H ), 6.30 (t,lH),
4.75(m,lH), 3.89 (m, 4H), 3.5- 3.9 (m, 4H), 3.20 (m, 2H), 3.09(m,4H), 2.52 (t, 2H).
(S)-N -[[ 3-(3 -fluoro -4- morpholinylphenyl) -2- oxo -5— oxazolidinyl] methyl] - 4
-[4- (2s',2'- dimethyl- 4 - ethylphenyl) -4- oxobutanamide.
34

!H NMR (CDC13, 8) : 7.75(d,2H ), 7.37 (d,2H ), 7.35(dd,lH ), 7.05 (dd,lH), 6.82(t,lH), 6.37
(t,lH), 4.71(m,lH), 3.5- 3.9 (m, 4H), 3.80 (m, 4H), 3.25 (dt, 2H), 2.97 (m,4H),2.54 (t, 2H),
1.26(s,9H).
(S) -N-ff 3 - (3 -fluoro - 4 -fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl] -4-(4- methoxyphenyl) -4- oxobutanamide.
lU NMR (CDC13, 8) : 7.76(d,2H ), 7.37 (dd,lH ), 7.16(m,5H ), 6.93 (dd,lH), 6.79(d,2H),6.74 (
t,lH), 6.37 (t,lH), 4.66(m,lH),4.14 (s,2H), 3.84(t,lH), 3.74 (s,3H), 3.4- 3.8 (m, 3H), 3.18 (dd,
2H), 2.62(s,3H),2.5 l(t, 2H).
(S) -N-ff 3 - (3 -fluoro - 4 - fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl]
methy] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide.
'H NMR (CDCU, 8) : 7.77(d,2H ), 7.37 (dd +d,3H ), 7.19 -7.22(m, 3H), 6.98 (dd,lH),
6.77(t,lH), 6.31 (t,lH), 4.69(m,lH), 4.17(s,2H), 3.89(t,lH)„3.72 (dd,lH), 3.5- 3.6 (m, 2H), 3.25
(dd, 2H), 2.64 (s,3H),2.55 (t, 2H), 1.25(s,9H).
(S) -N-ff 3 -(3 -fluoro - 4 -[methylbenzylamino]phenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl] -4- (2,4 - dimethylphenyl) -4- oxobutanamide.
lU NMR (CDCI3, 8) : 7.65(d,lH ), 7.46 (dd,lH ), 7.32(m,5H ), 7.04(m,3H), 6.95(t,lH), 6.36
(t,lH), 4.78(m,lH), 4.27(s,2H), 3.97(t,lH),3.6- 3.8 (m, 2H), 3.81 (t, IH), 3.27 (dd, 2H), 2.77
(s,3H),2.61 (t, 2H), 2.44(s,3H), 2.35 (s, 3H).
(S)-N -[[ 3-(3 -fluoro -4- tnorpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] - 4
- (2,4 - dimethylphenyl) -4- oxobutanamide.
'H NMR (CDCU, 8) : 7.652(d,lH ), 7.42 (dd,lH ), 7.0- 7.1(m,3H), 6.86(t,lH), 6.38 (t,lH),
4.79(m,lH), 3.95(t,lH),3.5- 3.9 (m, 2H), 3.87 (m, 4H), 3.25(dd, 2H), 3.02 (m,4H), 2.59 (t, 2H),
2.41(s,3H), 2.34 (s, 3H).
^ -N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) —2 — oxo -5 — oxazolidinyl] methyl] — 4 —
(2,4 - dimethylphenyl) - 4 - oxobutanamide.
JH NMR (CDCI3, 8) : 7.62(d,lH ), 7.31 (dd,lH ), 7.03(s,+dd, 3H ), 6.60(t,lH), 6.36 (t,lH),
4.74(m,lH), 3.94(t,lH), 3.76 (dd, lH),3.67(m, 2H), 3.30 (m, 4H), 3.24 (dt, 2H), 2.60 (t, 2H),
2.44(s,3H), 2.34 (s, 3H).1.94 (m,2H).
(S) -N-ff 3-(3-fluoro-4- benztriazolylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4-
(2,4- dimethylphenyl) -4-oxobutanamide.
!H NMR (CDCI3, 8) : 8.15(d,lH ), 7.80 (dd,lH ), 7.3 -7.7(m,6H ), 7.02(d,2H), 6.39 (t,lH),
4.87(m,lH), 4.07(t,lH), 3.96(t,lH), 3.89 (dq, IH), 3.75(dt,lH), 3.38 (qt, 2H), 2.62 (m, 2H),
2.39(s,3H), 2.26 (s, 3H).
(S) - N-ff 3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-
oxo -4-(2- thienyl)butanamide.
35

*H NMR (CDC13, 8) : 7.71(d,lH ), 7.63 (d,lH ), 7.31(dd,lH ), 7.11 (t, lH),7.05(dd,lH), 6.68(m,lH), 6.38 (t,lH), 4.74(m,lH), 3.95(t,lH), 3.77 (t, 1H),3.6- 3.7 (m, 2H), 3.36 (m, 4H), 3.28 (t, 2H), 2.63 (t, 2H), 1.96 (m,2H). (S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo - J - oxazolidinyl] methyl] - 4
- oxo -4-(2- thienyl)butanamide.
!H NMR (CDC13, 8) : 8.08(d,lH), 7.77(dd,lH ), 7.3 - 7.7(m,7H ), 7.02(t,lH), 6.45 (t,lH),
4.81(m,lH), 4.00(t,lH),3.7- 4.0 (m, 2H), 3.57 (dt, 1H), 3.25 (m, 2H), 2.55 (m,2H).
(3? -N-[[3-(3-fluoro-4- morpholinylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4-
oxo - 4 -phenylbut - 2- enamide.
JH NMR (CDCI3, 8) :7.92 (d,lH), 7.84 (,d,lH), 7.2 - 7.6 (m, 6H), 6.98 - 7.1 (m, 3H), 4.38(m,
1H), 3.5 - 4.1 (m, 4H), 3.84 (m, 4H), 3.03 (m, 4H).
(S) -N-[[3-(3 -fluoro-4- piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4-(4
- methoxyphenyl) - 4- oxobutanamide.
'HNMR^MSOde, 8) : 8.25 (t, 1H), 7.79 (d, 2H), 7.38 (dd, 1H), 7.71 (dd, 1H), 6.95 (t,lH), 6.93
(d, 2H + 1H), 4.65 (m,lH), 3.75 (s,3H), 3.99 (t, 1H), 3.64 (dd, 1H), 3.06 (t, 2H), 2.81(m,4H), 1.3
-1.6(m.6H).
(S) -N-[[3-(3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4
- chlorophenyl) - 4- oxobutanamide.
lH NMR (CDCI3, 8) : 7.73(d,2H ), 7.33 (d,2H ), 7.2 - 7.8 (m, 2H),6.96(dd,lH), 6.34 (t,lH), 4.72(m,lH), 3.84(t,lH), 3.5- 3.8 (m, 3H), 3.21 (dd, 2H), 2.98 (m, 4H),2.54(t,2H), 1.5 - 1.7 (m,6H).
(S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl] -4-(2,4 - dimethylphenyl) - 4- oxobutanamide.
'H NMR (CDCI3, 8) : 7.55(d,2H ), 7.4 (m,lH ), 6.9 - 7.0 (m, 3H),6.32(t,lH), 4.70(m,lH), 3.90(t,lH), 3.74 (t,lH), 3.5- 3.7 (m, 2H), 3.20 (dd, 2H), 2.9 - 3.1 (m, 4H),2.52(t,2H), 2.34 ( s,3H), 2.71 (s, 3H ), 1.5 -1.9 (m,6H).
(S) - N-[[3 - (3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- methoxyphenyl) -4-oxobutanamide.
XH NMR ( CDCI3, 8) : 8.07(d, 1H), 7.2 - 7.8 (m,6H), 7.71(d,2H ), 6.79 (d,2H ), 6.51(t,lH), 4.81(m,lH), 3.4- 4.0 (m, 4H), 3.71 (s, 3H), 3.15 (qt, 2H), 2.52 (dd, 2H).
(S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- chlorophenyl) -4-oxobutanamide.
'H NMR (CDCI3, 8) : 8.09(d, 1H), 7.2 - 7.8 (m,6H), 7.75(d,2H ), 7.35 (d,2H ), 6.29(t,lH), 4.81(m,lH), 3.7 - 4.0(m, 3H), 3.5 - 3.7 (bt, 1H),3.25 (qt, 2H), 2.55 (t, 2H). (S)-N-[[3-(3-fluoro-4-(1,2,4-triazolyl)phenyl)-2-oxo-5- oxazolidinyljmethyl] -4- oxo — 4 - phenylbutanamide.
36

*H NMR (CDCI3, 8) : 8.62 (bs, 1H ), 8.10 ( s, 1H ), 7.7 -7.8 ( m, 2H ),, 7.67 (dd, 2H, ), 7.44 (t,
1H ), 7.2 - 7.4 (m,3H ), 6.49 (t, 1H ), 4.78 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55 (dt, 1H ), 3.30 (ddd,
2H), 2.54 (dd, 2H).
(S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4-(4- methylphenyl) -4- oxobutanamide.
XHNMR (CDC13, 8) : 8.71 (bs, 1H ), 8.10 ( s, 1H), 7.7 -7.9 ( m, 4H ), 7.30 (d, 1H, ), 7.21 (d, 2H
), 6.63 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.64(dt, 1H ), 3.35 (qdd, 2H), 2.5 - 2.6 (m, 2H),
2.35( s,3H).
(S) - N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -
4-(4- methoxyphenyl) -4- oxobutanamide.
'H NMR (CDCI3, 8) : 8.68 (bs, 1H ), 8.16 ( s, 1H ), 7.7 -7.9 ( m, 2H ), 7.79( d, 2H ) 7.28 (dd,
1H), 6.85 ( d,2H), 6.58 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.82(s,3H), 3.61(dt, 1H ), 3.32
(qdd, 2H), 2.65 (ddd, 2H).
(S) -N-][3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl]
-4-(2,4- dimethylphenyl) -4- oxobutanamide.
!HNMR (CDCI3,8) : 8.69 (bs, 1H ), 8.17 ( s, 1H ), 7.78( t,lH), 7.75 ( d,lH ), 7.60 (d,lH),7.25(d,
1H, ), 7.10 (d, 1H ),6.99(s, 1H ), 6.54( t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.65(dt, 1H ),
3.25 (qt, 2H), 2.59 (dt, 2H), 2.38( s,3H), 2.29 (s,3H).
(S) -N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4- oxo- 4 -(4 - thiomethylphenyl)butanamide.
'H NMR (CDCI3, 8) : 8.57 (bs, 1H ), 8.06 ( s, 1H ), 7.77 (m,2H), 7.61 (d, 2H), 7.19 ( d, 1H ),
7.10 (d, 2H, ), 6.47 (t, 1H ), 4.76 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25 (qdd, 2H), 2.55
(dq,2H),2.39(s,3H).
(S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide.
lU NMR (CDCI3, 8) : 8.58 (bs, 1H ), 8.06 ( s, 1H ), 7.80(t,lH),7.6 -7.8 ( m, 1H ), 7.67 (d,
2H,),7.32(d,2H), 7.26 (d, 1H ), 6.43 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25
(qt, 2H), 2.53(dt, 2H), 1.22( s,9H).
(S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo -5- oxazolidinyl] methyl]
-4-(2'- methyl - 4 - propylphenyl) -4- oxobutanamide.
'H NMR (CDCI3, 8) : 8.61 (bs, 1H ), 8.09 ( s, 1H ), 7.6 -7.8 ( m, 4H ), 7.24 (dd, 1H, ), 7.07 (d,
2H ), 6.38 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.54(dt, 1H ), 3.28(qt, 2H), 2.54(dt, 2H),
2.40( d,2H), 1.77 (pent.,lH), 0.81 (d,6H).
(S) - N-[[ 3-(3 -fluoro -4- (1,2,4 — triazolyl) phenyl) -2- oxo -5— oxazolidinyl] methyl]
-4-oxo - 4- (2- thienyl)butanamide.
37

'HNMR (CDCI3, 8) : 8.57 (bs, IH ), 8.05 ( s, IH ), 7.76 (t,lH),7.60(dd,lH), 7.53 (dd,lH), 7.25
(dd, IH, ), 7.01 (d, 2H ), 6.47( t, IH ), 4.78 ( m, IH), 3.7 - 4.0 (m, 3H), 3.56(ddd, IH ), 3.25 (qt,
2H), 2.54 (dt, 2H).
(S) -N-[[3 -(3 -fluoro -4- (1,2,4-triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl]-
4 - (2-naphthyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) : 8.41 (s, IH ), 8.27( s, IH ), 8.02(s,lH), 7.3 -7.9 ( m,6H ), 7.3 - 7.6 (m,
3H), 6.44 (t, IH ), 4.77 ( m, IH), 3.7 - 4.0 (m, 3H), 3.2- 3.7 (m, 3H), 2.5-2.6 (m, 2H).
(S) - N-[[3 - (3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4-(4- chlorophenyl) -4- oxobutanamide.
lH NMR (CDCI3, 8) : 8.58 (bs, IH ), 8.07 ( s, IH ), 7.6 -7.9 ( m, 2H ), 7.68 (d, 2H), 7.29 (d,
2H,), 7.2 - 7.3 (m, IH ), 6.31 (t, IH ), 4.81 ( m, IH), 3.7 - 4.1 (m, 3H), 3.55(dt, IH ), 3.25 (qt,
2H), 2.55(dt, 2H).
(S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4-
oxo -4-(2- thienyl)butanamide.
*H NMR (CDCI3, 8) : 7..5 - 7.7 ( m, 2H), 7.3 - 7.5 (m,lH), 6.8 - 7.3(m,3H ), 6.35(t,lH),
4.69(m,lH), 3.89 (t,lH), 3.76(t,lH),3.59(m,2H), 3.21(dd,2H),3.02 (m, 4H), 2.55 (t, 2H), 1.5 -
1.8 (m,6H).
(S) -N-[[3 -(3-fluoro -4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4-
(2'- methyl -4- propylphenyl) -4- oxobutanamide.
'H NMR (GDCI3,8) : 8.08 (m, IH ), 7.74 (d, 2H), 7.4 - 7.8 (m, IH ), 7.16 (d, 2H,), 6.97(dd,lH)
6.37 (t, IH ), 4.74 ( m, IH), 3.88 (t, IH), 3.80(t,lH), 3.4 - 3.71 (m, 2H), 3.40(m,4H) 3.25(dd, 2H
), 2.45(d, 2H), 1.80 (pent, IH), 1.5-1.8(m,6H),0.83(d,6H).
(S)-N-[[3-(3-fluoro-4-piperidylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(4
- acetamidophenyl) -4- oxobutanamide.
'H NMR (DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.78 (d, 2H), 7.60 ( d, 2H), 7.36 (dd, IH),
7.06 (dd, IH), 6.93 (t,lH), 4.63 (m, IH), 3.95(t,lH), 3.61 (dd,lH), 3.07(dd,lH), 2.81 (m,4H),
1.99 (s, 3H), 1.55 (m, 4H), 1.44 (m, 2H).
(S) - N-ff 3 -( 3 -fluoro - 4 * piperidylphenyl) - 2 - oxo - J - oxazolidinyl] methyl] -4-
oxo - 4 -phenylbut - 2- enamide.
JHNMR (CDCI3, 8) .-7.7-8.0 (m,3H), 7.2 - 7.6 (m, 5H), 7.01 (d,2H), 6.98 (t, IH), 4.80(m, IH),
4.01(t,lH), 3.85(t,lH), 3.77 (t, 2H), 3.16 (m, 4H), 1.5 - 1.9 (m,6H).
(S) - N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] ~4-
oxo- 4-(4- thiomethylphenyl)butanamide.
lU NMR (CDCI3, 8) :7.70 (d,2H), 7.60 (bd,lH), 7.0 - 7.3 (m, 3H), 6.91 (d,lH), 6.47 (t, IH),
4.71(m, IH), 3.87(t,lH), 3.4 - 3.8 (m,3H ), 3.45(m, 4H) 3.21 (dd, 2H), 2.54 (t, 2H), 2.45 (s,3H),
2.06(m,4H).
38

(S)-N-[[3-(3-fluoro-4-pyrrolidinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(2-naphthyl) -4- oxobutanamide.
!H NMR (CDC13, 8) : 8.35 (s, IH ), 7.5 - 8.1 (m, 8H ), 6.91(d,lH) 6.53 (t, IH ), 4.72 ( m, IH),
3.38 (m, 4H), 3.2 - 4.0 (m, 6H), 2.61(m, 2H), 1.99 (m,4H).
(S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] — 4 —
(2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide.
lU NMR (CDCI3, 8) :7.75 (d,2H), 7.46 (m,lH), 7.1 - 7.3 (m, 3H), 6.95 (d,lH), 6.44 (t, IH),
4.70(m, IH), 3.3 - 4.0 (m,4H ), 3.41(m, 4H) 3.24 (dd, 2H), 2.55 (t, 2H), 2.45 (d,2H),
2.01(m,4H), 1.81 (pent,lH), 0.83 (d, 6H).
(S) -N-][3-(3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-
(2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide.
lH NMR (CDCI3, 8) :7.76 (d,2H), 7.2 7.5(m, 4H), 6.95 (d,lH), 6.33 (t, IH), 4.69(m, IH),
3.88(t,lH), 3.71(t,lH), 3.6 - 3.7 (m,2H ), 3.45(m, 4H) 3.23 (dd, 2H), 2.56 (t, 2H), 1.94 (m,4H),
1.26(s,9H).
(S^J - N-[[3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4 —
(4 - acetamidophenyl) -4- oxobutanamide.
'H NMR (CDCU, 8) : 7.2 - 7.8 (m, 7H), 6.85 (d,lH), 6.47 (t, IH), 4.67(m, IH), 3.81(t,lH), 3.3 -
3.7 (m,3H ), 3.46(m, 4H) 3.16 (m, 2H), 2.3 - 2.9 (m,6H), 2.06(s,3H).
(Sp -N-[]3-(3-fluoro -4- pyrrolidinylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4-
oxo - 4 -phenylbut - 2- enamide.
'HNMR (CDCI3, 8) :7.8 - 7.9 (m,3H), 7.0 - 7.6 (m, 5H), 6.93 (d,lH), 6.75 (m,lH), 4.76(m, IH),
4.02(t,lH), 3.74 (m, 3H), 3.30 (m, 4H), 1.95 (m,4H).
(S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-
4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
!HNMR (CDCI3, 8) :7.78 (d,2H), 7.33 (dd,lH),6.99 (d,lH), 6.83 (t,lH), 6.81 (d, 1H),6.38 (t, IH)
4.69(m, IH), 3.86 (t,lH), 3.79 (s,3H), 3.5 - 3.8 (m,3H ), 3.41(m, 4H) 3.20 (m, 6H), 2.73(m,4H)
2.53 (t, 2H).
(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-
4 - (2,4 - dimethylphenyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) :7.55 (d,lH), 7.33 (dd,lH), 6.96 (m,3H), 6.81(t,lH), 6.22 (t, IH), 4.69(m,
IH), 3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.17(m, 6H) 2.73 (t, 2H), 2.45 (d,2H),2.51 (t,2H), 2.34(s,3H),
2.27 (s,3H).
(Si)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-
4 - oxo -4-(2- thienyl)butanamide.
!H NMR (CDCI3, 8) :7.63 (d,lH), 7.55 (d,lH), 7.33 (dd, IH), 7.05 (dd,2H), 6.85(t, IH), 6.31
(t,lH), 4.69(m, lH),3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.23(m, 6H) 2.73 (m, 4H), 2.55 (t, 2H).
39

(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - J - oxazolidinyl] methyl] -4-(4- acetamidophenyl) -4- oxobutanamide.
'HNMR ( DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.73(d, 2H), 7.59 (d, 2H), 7.38 ( dd, IH), 7.08(dd,lH), 6.99 (t, IH), 4.65 (m, IH), 3.95(t,lH),3.62(dd,lH), 3.08(m, 6H), 2.66 (m, 4H), 1.97 (s,3H).
(S) - N -[[ 3 - (3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] - 4 -oxo - 4 - (4 - thiomethylphenyl)butanamide.
•HNMR (CDC13,8) : 7.70 (d, 2H), 7.32 (dd,lH),7.14 (d, 2H,), 6.99(dd,lH), 6.82(t,lH), 6.33 (t, IH ), 4.68 ( m, IH), 3.86 (t, IH), 3.4 - 3.8 (m, 3H), 3.20(dt, 2H ), 2.90(t,4H) 2.53(t, 2H), 2.44(s,3H), 1.67 (m,4H), 1.5 (m,2H).
(S) -N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl] -4-(naphthyl) -4- oxobutanamide.
'H - NMR ( CDCI3) : 8.36 (s, IH ), 7.7 - 7.9 (m, 4H, ), 7.4 - 7.6 (m, 2H ), 7.32 (dd,lH), 6.99(d,lH), 6.78(t,lH), 6.43 (t, IH), 4.70 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.39(dt,2H), 2.86(t,4H), 2.61(t, 2H), 2.10(m,4H),1.50 (m,2H).
S) -N-[[ 3- (3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide.
lUNMR (CDCI3,8) : 7.75 (d, 2H), 7.37 (d,2H),7.31 (dd, IH, ), 7.00(dd,lH), 6.84(t,lH), 6.37 (t, IH ), 4.68 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.25(dt, 2H ), 2.91(t,4H) 2.54(t, 2H), 2.23(m,4H), 1.5 (m,2H), 1.26(s,9H).
(S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4-oxo -4-(4- thiomethylphenyl)butanamide.
'HNMR (CDCI3, 8) : 8.08 (d, 2H ), 7.77 (dd, IH, ), 7.63(d,2H), 7.2 - 7.5 (m, 4H ), 7.12 (d,2H), 6.41 (t, IH ), 4.81 ( m, IH), 3.98 (t, IH), 3.7 - 3.9 (m, 2H), 3.54(dt,lH), 3.22(qdd,2H), 2.54(dd, 2H), 2.36(s,3H).
(S) -N-[] 3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5 - oxazolidiny] methyl] -4-(2-naphthyl) -4- oxobutanamide.
'HNMR (CDCI3, 8) : 8.35( s,lH), 8.08 (d, IH ), 7.6 - 7.8(tn,5H), 7.2 - 7.6 (m, 7H ), 6.41 (t, IH ), 4.82 ( m, IH), 3.8 - 4.0 (m, 3H), 3.3 - 3.7(m,3H), 2.64(dd, 2H).
(S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4 - (2',2' - dimethyl- 4 - ethylphenyl) -4- oxobutanamide.
*H NMR (CDCI3, 8) : 8.08 (d, IH ), 7.80 (dd, IH, ), 7.70(d,2H), 7.57(t, IH), 7.2 - 7.5 (m, 4H ), 7.08 (d,2H), 6.41 ( t, IH ), 4.80 ( m, IH), 3.7 - 4.0 (m, 3H), 3.55(dt,lH), 3.1 - 3.4(m,2H), 2.54(dd, 2H), 2.37(d,2H), 1.72(pent,lH), 0.76(d,6H).
40

(S)-N-[[3-(3-Jluoro-4- henzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide.
JHNMR(CDC13, 5) :7.2 - 8.0 (m,13H), 6.95 (d,lH), 6.65 (m,lH), 4.89(m, IH), 4.18(t,lH), 3.7-4.0 (m, 3H).
(S) -N-[[3-(3-Jluoro-4-benztriazolylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 -(4- acetamidophenyl) -4- oxobutanamide.
!HNMR (DMSOde, 8) : 10.16 (s, IH), 8.29(t, IH), 8.12 (d, IH), 7.79 (m, 4H), 7.58 ( d, 2H), 7.4 - 7.5 (m, 4H), 4.74 (m, IH), 4.13(t,lH),3.08(dd,lH), 3.10 (t, 2H), 1.97 (s, 3H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide.
lH NMR (CDCI3,8) : 7.76 (d, 2H), 7.53 (dd, 1H),7.39 (d, 2H +1H, ), 7.02(d,lH), 6.29 (t, IH ), 4.71 ( m, IH), 3.89 (t, IH), 3.79(t,lH), 3.5 - 3.7 (m, 2H), 3.38(m, 4H ), 3.24 (dd,2H), 2.92(m,4H) 2.54(t, 2H), 1.26(s,9H).
(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide.
JH NMR (CDCU, 8) :7.8 - 7.9 (m,3H), 7.3 - 7.7 (m, 5H), 6.8 -7.0 (m,3H), 4.81(m, IH), 4.05(m,lH), 3.75 (m, 3H), 3.49 (m, 4H), 3.10 (m,4H).
(S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(fi- naphthyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) : 8.35 (s, IH), 7.7-8.0 (m, 4H), 7.3-7.7 (m, 5H), 7.01 (m, IH), 6.48 (m, IH), 4.74 (m, IH), 3.80 (m, 3H), 3.60 (m, IH), 3.37 (m, 6H), 2.93 (m, 4H), 2.60 (m, 2H) (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4- (4- chlorophenyl) -4-oxobutanamide.
!H NMR (CDCI3, 8) : 7.74 (d, 2H), 7.54 (d, IH), 7.34 (d, 2H+1H), 6.98 (d, IH), 6.35 (t, IH), 4.78 (m, IH), 3.88 (t, IH), 3.5-3.8 (m, 3H), 3.38 (m, 4H), 3.22 (dd, 2H), 2.93 (m, 4H), 2.54 (t, 2H).
(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4 - (2,4 - dimethyl- 4 ethylphenyl) -4- oxobutanamide.
lH NMR (CDCI3, 8) : 7.95 (m, IH), 7.74 (d, 2H+1H), 7.77 (d, 2H), 7.07 (d, IH), 6.38 (t, IH), 4.76 (m, IH), 3.91 (t,lH), 3.4-3.8 (m, 3H), 3.58 (m,4H), 3.25 (dd, 2H), 3.1 (m, 4H), 2.54 (t, 2H), 2.46 (d, 2H), 1.80 (pent, IH), 0.85 (s, 3H), 0.82 (s, 3H). Microbiology: Pharmacological testing
The compound of formula (I) of the present invention displayed antimycobacterial activity when tested by in vitro growth inhibition assay and agar incorporation methods. The minimum inhibitory concentrations (jag/ml) obtained for representative compounds of formula (I)
41

against M. tuberculosis including sensitive and resistant strains are summarized in Table-I. The MIC value of a representative preferred Compound No. 30 of formula I against different species of mycobacteria is summarized in Table-II. in vitro Growth Inhibition assay
The ability of the compounds 1-78 of formula (I) of this invention to inhibit the growth of Mycobacterium species was determined by the BACTEC 460 TB system. The reference strain M tuberculosis H37Rv ATCC 27294 was grown in Middlebrook 7H9 broth containing 10% ADC
supplement at 37°C on a rotay shaker at 150 rpm for grown for 7days. The turbidity of the culture was adjusted to 1.0 Mc farland. The BACTEC 7H12B medium vials were seeded with 0.1ml of the 1.0 Mc farland adjusted M. tuberculosis culture. In the control vials 0.1ml of the culture was added after lOOfold dilution of the initial inoculum. Stock solution of lmg/ml of each compound was prepared in DMSO in separate sterile tubes. The compounds were further diluted to concentration of 25 ^g/100 ul, 0.1ml was than added to the 7H12B vial containing mycobacterial culture so that final concentration of the compound 6.25 u.g/ml. The cap in all the vials were cleaned with isopropanyl alcohol and kept in racks. The vials were then incubated at 37°C without shaking. Test vials was read daily on the BACTEC system till the GI of the control vial reached > 30.Once the GI in the control reached 30 AGI (GI = GI (n> - GI („.i) ) was determined for all test and control vials. If AGI of test vial is less than that of the control vial the culture was sensitive to the test compound. in vitro Agar Dilution assay
MIC of compound of formula (I) of this invention against strains of Mycobacterium were determined by a reference agar dilution method as per the NCCLS- M24-T2. recommendations. The compounds were dissolved in DMSO and diluted twofold to obtain ten serial dilutions of each compound. Appropriate volume of compounds were incorporated into duplicate plates of Middlebrook7H10 agar medium supplemented with 10% Middlebrook supplement oleic acid-albumin-dextrose (OADC) enrichment at concentration of 0.03u,g/ml to 16|j,g/ml. Test organisms (mycobacterium strains) were grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement. After 7 days of incubation at 37°C the broths were adjusted to the turbidity of 1.0 McFarland standard; the organism were further diluted 10 fold in sterile water containing 0.10% Tween-80. The resulting mycobacterial suspensions were spotted (3-5jxl/spot) onto drug supplemented 7H10 media plates. The plates were sealed and incubated at 37°Cfor 3-4 weeks in upright position. The MIC was recorded as the lowest dilution of the drug that completely inhibited the growth of test organisms. Test isolates included 10 clinical isolates that were generally susceptible to common tubercular agents and 10 strains that were resistant to one or more standard anti tubercular drugs. Appropriate reference strains and control drug was included in each batch of test.
42

in vivo studies:
The efficacy of the compound of formula (I) of this invention was also evaluated in murine model of pulmonary tuberculosis. Mycobacterium tuberculosis cultures grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement at 37°C for 7 days on a rotary shaker. For, animal inoculation liquid cultures were declumped by brief sonication and were diluted appropriately in 7H9 broth to obtain a concentration of lxl07CFU's/ 0.2ml. Four-week-old male outbred Swiss albino mice housed in a pathogen free, biosafety level 3 environment within micro isolator cages were used throughout the study. Infections were produced by intravenous inoculation into caudal tail vein of 0.2ml of declumped M. tuberculosis suspension. Following infection, mice were randomly distributed in different groups of six each.
Treatment for initial study was started one day after infection. For, treatment Compound No. 30 of formula I was dissolved in 10% PEG. Isoniazid was dissolved in sterile water. The drugs were prepared each morning prior to administration. Therapy was given 5 days per week for four weeks. All the agents were administered by gavage and were dosed at 50,25,12.5mg / kg of body weight. Control group of infected but untreated mice were killed at the initiation of therapy (early control) or at the end of the treatment period (late control). Mice were sacrificed by cervical dislocation 3-5 days after the administration of the last dose of drug. The spleens and right lung were removed aseptically and homogenized in tissue homogeniser. At least 4 serial tenfold dilution of the homogenate was plated onto selective Middlebrook 7H11 agar plates in duplicate. The colony counts were recorded after incubation at 37°C for 4 weeks. The viable cell counts were converted to Logio values. A compound showing 2 Log reduction in viable counts compared to the controls was considered significant.
The in vivo data for a representative compound of formula (I) is given in Table-II.
Acute toxicity of Compound No. 30 of Chart-I was estimated in mice and the LDo was found to be >1000 mg/kg P. O.
43

Table-I: in vitro activity of compounds 1 to 58 of formula (I),

Compound No. Growth inhibition of
M.tuberculosis
27294 MIC (fig/ml) against

M.tuberculosis 27294 Clinical isolates

Sensitive Resistant
1 + 16 4-16 >16
2 + 8 8 8
8 + 2 .5-2 2-4
13 + 2 2 2-4
14 + 0.25 0.25-0.5 4->16
15 + >16 >16 >16
16 + 0.5 0.5 0.5(>16)
17 + 0.5 1.0 0.5-1.0
18 + 4- 1-4 8->16
19 + 2 1-2 2
20 + 1 1-2 2-4
21 + 0.5 0.5-2 0.5(>16)
25 + 4 4-16 4->16
27 + >16 >16 >16
28 + 0.5 1-2 2-8
30 + 0.5 0.5 0.5-2
31 + 1 1-2 1-4
32 + 0.25 0.25-0.5 4-(>16)
33 + 0.5 1 0.5-2
34 + >16 >16 >16
35 + 4 2-4 4-8
36 + 4 4-8 4-8
44

Table-I Contd....

39 + 2 2-4 2-8
40 + 1 1-2 1-2
43 + 1 0.5-1.0 1-2
44 + 1 0.5-2 1-4
45 . + 2.0 2-4 2-4
46 + 2 2-4 2-8
47 + 1 1-2 2-4
48 + 2 2-4 2-8
49 + 4 4-16 4-16
50 + 2 2-4 2-4
51 + 8 8->16 8->16
52 + 2 2 4->16
53 + >16 >16 >16
54 + 8 8-16 >16
55 + >16 >16 >16
56 + >16 >16 >16
57 + 16 16->16 >16
58 + 8 8-> 16 8-> 16
Isoniazid + 0.25 0.12- .25 8 - >16
Linezolid + 0.5 0.25-0.5 1.0-2.0
Table-II MIC values of compound of formula (I) against different species ofMycobacteria

Sr.
No. Compound No. MIC (ug/ml)

M. tuberculosis M.avium-
intracellular
complex M.fortuitum M.kansai

Sensitive Resistant

1 Compound 30 of formula I 0.50 0.50-2.0 8.0->16.0 >16.0 8.0
2 Isoniazid 0.25 4.0-> 16.0 8.0->16.0 >16.0 >16.0
45

Table-m in vivo activity of Compound of formula (I) against M. tuberculosis ATCC 27294" infection
in Swiss albino mice

Sr. No. Drug& Dose b (mg/kgday" ') or group Mean Logio No. of CFU Mean Logio No. of reductionc

Lung Spleen Lung Spleen
1 Compound 30 of Chart-I
50mg/kg 25mg/kg 12.5mg/kg 2.12 2.21 4.34 2.09 2.13 4.30 2.40 2.30 0.20 2.53 2.49 0.26
2 Isoniazid
50mg/kg 25mg/kg 12.5mg/kg 2.03 2.11 2.95 1.92 2.11 2.94 2.49 2.41 1.57 2.70 2.51 1.68
3 Infected early control 4.52 4.62
4 Infected late control 6.57 6.37
a- inoculation of logio:- 7.00 Mycobacteria.
b- mice were dosed 5 day/week for 4 weeks. From day 1 -28.
c- difference in mean logio number CFU from that of early controls.
The compound of formula I of this invention may be administrated to a subject such as a human being or an animal in need of such an administration through any route appropriate to the condition to be treatede. Suitable routes of administration include oral, rectal, nasal, topical (both buccal and sublingual), vaginal and parenteral (including subcutaneous, intramuscular, intradermal, intrathecal and epidural).
Pharmaceutical compositions of compound of formula I can be prepared in adjunction with inert pharmaceutically acceptable carriers, which can either be solid or liquid.
Solid form preparations include powders, tablets, dispersible granules, capsules, cachets, suppositories and ointments. The solid carriers can be one or more substances which may act also as diluents, flavouring agents, solubilisers, lubricants, suspending agents, binders or tablet disintegrating agents. It can also be finely divided solid which is in admixture with finely divided active compound. Suitable solid carriers are lactose, pectin, dicalcium phosphate, microcrystalline cellulose, sucrose, kaolin, dextrin, gelatin, starch, tragacanth, low melting wax, coca butter and the like.
Liquid preparations include solutions, suspensions and emulsions, e.g. solutions of compound of formula I in water or water-propylene glycol mixture for parenteral injection. Liquid preparations can also be formulated along with non-ionic surfactants and edible oils such as corn, peanut and sesame oils. Aqueous solutions for oral use can be prepared by dissolving the active component in water and adding suitable colorants, flavours stabilizing and thickening
46

agents, as required. Aqueous suspension for oral use can be made by dispersing the finely divided active component in water with a viscous material, e.g. natural or synthetic gums, resins, methyl cellulose, sodium carboxymethyl cellulose and othe known suspending agents. The adjuvants may also include preserving agents and anti-oxidants.
Compositions for topical application may take the form of liquids or gels, containing a therapeutically effective concentration of compound of formula I admixed with a dermatologically acceptable carrier.
The pharmaceutical preparations may be in unit dosage form. In such form, the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage can be in the form of tablets, capsules, powdersin vials or ampoules, ointments, gels, creams or any other form. The quantity or concentration of the active compound in such unit dose preparations may be varied or adjusted according to the particular application and potency of the active ingredient.
47

A compound of formula (I) and its pharmaceutical^ acceptable salts

wherein,
A is either hydrogen or fluorine,
B is either hydrogen or fluorine,
A and B together is hydrogen and fluorine,
Ri is a group of formula,

wherein,
Q is either an alkyl group of two carbon atoms, an alkene group of two carbon atoms or
an alkyne group of two carbon atoms
Y is oxygen, sulfur or an amino function of formula NR3
wherein,
R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be
straight or branched; cycloalkyl of 3-7 carbon atoms; CHO, -COOH, -COOR,; COCR,;
CN; aryl or heteroaryl
wherein,
Rt is an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of
3-6 carbon atoms.
Ar is a substituted phenyl ring or a substituted pyridine ring of formula

—O-R3
or Ar is a five membered ring of formula
48

or Ar is a fused bicyclic phenyl or pyridine ring of formula

wherein,
M is either CH or N
Z is CH, NH, O, or S,
X is a group selected from OR,, NR4R5, N02, SR,, SOOR,, SOONR4R5, F, CI, Br or I,
wherein R4 is as defined hereinbefore, and
and R3 is as defined hereinbefore
R5 is hydrogen or R4
R2 is selected from the groups shown below, and the corresponding N-oxides thereof.

A compound according to Claim 1 wherein in said compound of formula I Aryl is phenyl substituted with (0) or (1) of F, CI, "OCH3, "OH, "NH2, CrC4 alkyl, 0-C(0)-OCH3," N02or"CN.
49

3. A compound according to Claim 1 wherein said compound of formula I is selected from the group consisting of:
1) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl
] methyl ] - 4 - oxo - 4 - phenylbutanamide.
2) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
3) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
4) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide.
5) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
6) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
7) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide.
8) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
9) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
10) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
11) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide.
12) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide.
13)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
14) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide.
15) (S) - N -[ [ 3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide.
16) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl 1 methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide.
17) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
50

18) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
19) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl]-4-oxo-4-(2-thienyl)butanamide.
20) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
21)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide.
22) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
23) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
24) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
25) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
26) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) — 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
27) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
28) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide.
29) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide.
30) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide.
31)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (2 - thienyl)butanamide - N - oxide.
32) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide.
33) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N -oxide.
34) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
51

35) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4- oxobutanamide.
36) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4- oxobutanamide.
37) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4- oxobutanamide.
38) (S) - N -[ [ 3 - (3 - fluoro - 4 - benztriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
39) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
40) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
41) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4 - oxobutanamide.
42) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
43) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
44) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide.
45) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
46) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
47) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide.
48) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide.
49) (S) - N .-[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
50) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
51) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
52) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide.
52

53) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
54) (S) -N-[[3-(3- fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
55) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
56) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -■ ( 4 - thiomethylphenyl )butanamide.
57) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2 - naplrthyl) - 4 - oxobutanamide.
58) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide.
59) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
60) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
61)(S)-N-[[3-(3- fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
62) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
63) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
64) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide.
65) (S) - N -[ [ 3 - ( 5 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
66) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (4 - thiomethylphenyl)butanamide.
67) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
68) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
69) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide.
70) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
53

71) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
72) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
73) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
74) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
75) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
76) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) --2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2 - naphthyl) - 4 - oxobutanamide.
77) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - '2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
78) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -
oxazolidinyl ] methyl ] - 4 - (2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide.
- '
4. A compound as claimed in claim 3 wherein said compound of formula I is selected from the group of N-oxide of the said compounds 1 to 78.
5. A pharmaceutical composition comprising a) atleast one of I) any compound of claims 1 to 4 and II) its pharmaceutically acceptable salts and b) a pharmaceutically acceptable carrier.
6. A pharmaceutical composition according to claim 5 comprising a solid or liquid preparation.
7. A pharmaceutical composition as claimed in anyone of claims 5 to 6 for oral or parenteral administration.
8. A method of preparation of the compound of formula I and/or its pharmaceutically acceptable salts comprising:
coupling of the amino fragment of compound of formula II
5^

(II)

with a carboxylic acid of formula III in the presence of an acid activating group or a dehydrating agent in a suitable solvent.

(Ill)

wherein R2 has the same meaning as given in claim 1.
9. A method as claimed in claim 8 wherein the compound of formula II is preferably selected
from (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 -
oxazolidinyl] methyl amine, (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 -
oxo - 5 - oxazolidinyl] methyl amine,(S) - N -[3 - ( 3 - fluoro - 4 -
benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3
- (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, S) - N -[3 - (3 - fluoro - A - benzotriazolylphenyl) - 2 - oxo - 5 -oxazolidinyl] methyl amine, and (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine.
10. A method as claimed in anyone of claims 8 or 9 wherein the compound of formula III is
selected from 4-(2-Naphthyl)-4-oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic acid, 4-oxo-4-(2' methy lpropyl)phenylbutanoic acid, 4-Oxo-4-(2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 -
5S

oxobutanoic acid,4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 -
methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid,
. 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -difluorophenyl) - 4 -
oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 -
oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 -
phenyl - but - 2 - ynoic acid.
11. A compound of formula I, its pharmaceutically acceptable salts and pharmaceutical compositions obtained thereof substantially as herein described and illustrated.
Dated this 5th day of March 2005
Dr. Sanchita Ganguli
Of S. MAJUMDAR & CO.
Applicants' Agent
5t
F0RM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. - OXAZOLIDINONE DERIVATIVES, PROCESS FOR THEIR
PREPARATION AND THEIR USE AS ANTIMYCOBACTERIAL AGENTS
2. Applicants)
(a) NAME : LUPIN LIMITED
(b) NATIONALITY : An Indian Company
(c) ADDRESS : 159, C.S.T. Road, Kalina, Santacruz (East),
Mumbai - 400 098, Maharashtra, India
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed

FIELD OF THE INVENTION
The present invention relates to novel compounds belonging to the class of oxazolidinones useful in the treatment of acid fast organisms such as Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium spp. The present invention further relates to methods for preparation of the novel compounds and to pharmaceutical compositions containing the novel compounds useful in the treatment of tuberculosis. BACKGROUND OF THE INVENTION
Tuberculosis (TB), an infectious disease caused by the bacterium Mycobacterium tuberculosis is transmitted mainly through air, affecting most often the lungs. When persons with pulmonary TB cough they produce tiny droplet nuclei containing M. tuberculosis, which remain suspended in air for a prolonged period of time. A person who breathes the air containing the aforesaid droplet nuclei containing M. tuberculosis can become infected with TB.
TB, one of the three major infectious diseases in the priority list of the World Health Organization's (WHO) agenda kills about two million people around the world every year. About six million new cases are reported every year and nearly 20% of adult deaths and 6% of infant deaths are attributable to the disease (C. Dye et. al., J. Am. Med. Ass., 1999, 282, 677-686). About a billion people are expected to be affected by TB by the year 2020, with 35 million likely to succumb to the disease (WHO Fact Sheet No. 104, Global Alliance for TB Drug Development- Executive Summary of the Scientific Blueprint for TB Development : http://www.who.int/inf-fs/en/factl04.html).
With the emergence of the AIDS epidemic and the increase in cases of HIV coupled with TB as well as the continued resistance of M. tuberculosis to isoniazid and rifampicin, the two most powerful anti-tubercular drugs available today there is an urgent need for new anti-tubercular drugs to combat the killer disease (S. H. E. Kaufmann et. al., Trends Microbiol., 1993, 1,2-5 ; B. R. Bloom et. al., N. Engl. J. Med., 1998, 338, 677-678).
Although, many new compounds are becoming available for fighting a number of infectious diseases, the number of such compounds having antimycobacterial activity are few. This could partly be due to the complexity of research involved and partly due to business considerations (B. N. Roy et. al., J. Ind. Chem. Soc, April 2002, 79, 320-335 and references cited therein).
However, renewed thrust in research in the last decade has resulted in development of new antimycobacterial compounds,
a) differing widely in structures,
b) having different mode/mechanism of action,
c) possessing favourable pharmacokinetic properties,
d) which are safe and have low incidence of side-effects, and
e) which provide a cost-effective dosage regimen.
2

Among the aforesaid new compounds, the oxazolidinones first developed during the mid-1980s (W. A. Gregory et. al., J. Med. Chem., 1989, 32,1673-1681 and 1990,33,2569-2578 ; C-H Park et. al., J. Med. Chem., 1992, 35, 1156-1165) are a unique class in themselves. The in vivo results for some of the oxazolidinones show that they are active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, including resistant strains such as methicillin-resistant Staphylococcus aureus [MRSA], methicillin-resistant Streptococcus epidermidis [MRSE], penicillin-resistant Streptococcus pneumoniae [PRSP], vancomycin-resistant enterococci [VRE], etc. (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999,9 (5), 625-633 and the references contained therein).
The oxazolidinones inhibit bacterial protein synthesis at a very early step in the initiation of complex formation involved in the process of translating mRNA into protein. The oxazolidinones, in general, are not cross-resistant with any known antibiotic because of this unique mechanism (D. C. Eustice et. al., Antimicrob. Agents Chemother., 1988, 32, 1218 and Biochem. Biophys. Res. Commun., 1988,150. 965).
A feature of the oxazolidinone molecule is that only those compounds, which are enantiomers with a (5S)-acetamidomethyl configuration in the left side of the molecule are known to exhibit antibacterial activity (W. A. Gregory et. al., J. Med. Chem., 1989, 32, 1673-1681). Another feature is that most of such antibacterial compounds invariably carry a (substituted) phenyl ring attached to the nitrogen atom of the oxazolidinone ring in the right side of the molecule (B. Riedl et. al., Exp. Opin. Ther. Patents., Ashley Publications Ltd., 1999, 9 (5), 625-633 and the references contained therein).
The most promising compound among the N-phenyl oxazolidinones, which has been approved for human use is (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidin-yl]methyl]-acetamide), commonly known as linezolid (M. Barbachyn et. al., WO 995/07271). Linezolid possesses good in vitro and in vivo potency against most of the Gram-positive bacteria, including resistant strains {Drugs of the Future, 1996,21.(11), 1116-1123).
The left hand side i. e. position 5- and the right hand side i. e. position 3- respectively of
the oxazolidinone ring nucleus allows for many variations and has resulted in the discovery of a
large number of compounds having antimicrobial and antibacterial properties. Such
representative compounds, albeit not meant to be limiting are disclosed in the following prior art
references. These are:
i) US 4,942,183 (Gregory et. al.) and US 4,948,801 (Carlson et. al.) collectively disclose
certain 3-substituted phenyl- 5-aminomethyl oxazolidinones, possessing useful
antibacterial activity, ii) US 5,529,998 (Habich et. al.) discloses certain 3-benzoxazoyl- and benzothiazolyl-5-
acetyl amino methyl oxazolidinones, useful as antibacterial medicaments.
3

iii) US 5,565,571, US 5,654,428, US 5,756,732, US 5,801,246 and US 5,929,248 (Barbachyn et. al.) collectively disclose several substituted aryl and heteroaryl phenyloxazolidinones carrying an acetyl aminomethyl function at the 5-position, specifically oxazolidinones having an aryl or heteroaryl group at the para position of the 3-phenyl ring and additional substituents at the meta positions of the 3-phenyl ring, which are useful as antibacterials.
iv) US 5,652,238 (Brickner et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a hydroxyl acetyl piperazine moiety, active against various Gram-positive bacteria such as staphylococci, pneumococci and enterococci, as well as anerobic organisms such as bacteroides and Clostridia species as well as acid-fast organisms such as Mycobacterium tuberculosis.
v) US 5,684,023 (Riedl et. al.) discloses certain 3- benzofuranyl- and benzothienyl oxazolidinones, carrying an azido, hydroxy or acetyl aminomethyl group at the 5-position, useful as antibacterial medicaments.
vi) US 5,688,792 (Barbachyn et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a (substituted)-morpholine. Such compounds are useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp.
vii) US 5,719,154 (Tucker et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the said substitution being a pyrimidinyl or pyradazinyl group. Such compounds are useful as antimicrobial agents.
viii) US 5,736,545 (Gadwood et. al.) discloses certain 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a five membered heterocycle ring, in particular an azolyl ring. Such compounds are useful in the treatment of microbial infections.
ix) US 5,792,765 (Riedl. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-substituted phenyloxazolidinones, the substitution being a heterocyclic moiety, useful as antibacterial medicaments.
x) US 5,861,413 (Habich et. al.) discloses certain 2-oxo and 2-thio-l,2-dihydroxyqoinolinyl-1-oxazolidinones, useful as antibacterial medicaments.
xi) US 5,880,118 (Barbachyn et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a
4

substituted thiomorholine moiety i. e. oxazine and thiazine derivatives, useful for treatment of microbial infections caused by staphylococci, streptococci, enterococci, Bacteroides spp., Clostridia spp., Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium spp.
xii) US 5,910,504 and US 6,124,334 (Hutchinson et. al.) collectively disclose certain substituted 5-acetyl aminomethyl-3- phenyloxazolidinones substituted at the para position of the 3-phenyl ring with a heteroaromatic moiety, which is five membered having one to four nitrogen atoms or alternatively, a benzoannulated five-membered heteroaromatic ring having one to four nitrogen atoms, useful as antibacterials.
xiii) US 6,069,160 (Stolle et. al.) discloses certain substituted 5-acetyl aminomethyl-3-benzocyclopentaneoxazolidinones, containing an heteroatom, useful as antibacterial medicaments.
xiv) US 6,227,868 Bl and US 6,410,728 (Sciotti et. al.) collectively disclose certain 5-acetyl aminomethyl-3-phenyloxazolidinones carrying an acetylenic moiety on the 3-phenyl ring, useful for treating bacterial infections, psoriasis, arthritis and toxicity due to chemotherapy.
xv) WO 93/23384 (Hutchinson et. al.) discloses certain substituted 5-acetyl aminomethyl-3 -phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, useful for treatment of microbial infections caused by staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium.
xvi) WO 97/10223 (Gadwood et. al.) discloses certain substituted 5-acetyl aminomethyl-3-aminoaryl oxazolidinone N-oxide compounds, which are exceedingly water soluble and useful in preparation of pharmaceutical compositions for combating a number of human and veterinary pathogens, staphylococci, streptococci, as well as anaerobic organisms such as bacteroides and Clostridia species and acid-fast organisms such as Mycobacterium tuberculosis and Mycobacterium avium, Mycobacterium spp. and Mycoplasma spp.
xvii) WO 98/01446 and WO 98/01447 (Betts et. al.) collectively disclose certain substituted 5-acetyl aminomethyl3-phenyloxazolidinones, substituted at the para position of the 3-phenyl ring with a substituted piperazine moiety, the substitution being a six-membered heteroaryl ring containing two or three ring nitrogen atoms as the only ring heteroatoms, useful as antibacterial agents.
xviii) WO 99/02525 (Thomasco et. al.) discloses certain substituted 5-acetyl aminomethyl-3-phenyloxazolidinones, substituted by a thiadiazolyl or oxadiazolyl moiety, useful as
5

antimicrobial agents, effective against a number of human and veterinary pathogens, including Gram-positive and Gram-negative aerobic bacteria.
xix) WO 99/37630 (Gordeev et. al.) discloses oxazolidinone combinatorial libraries, compositionscontaining the same and methods of preparation thereof involving solid phase synthesis, which provides the said compounds for high-throughput screening.
xx) W099/37641 (Bartel. et. al.) discloses certain substituted 5-acetyl aminomethyl-3-bicyclene-substituted oxazolidinones, useful as antibacterial medicaments.
xxi) WO 01/09107 (Gordeev et. al.) discloses certain 3-heteroaryl-5-acetyl aminomethyl oxazolidinones, substituted by a thioacyl, aminocarbonyl, alkoxycarbonyl, aminothiocarbonyl, alkoxythiocarbonyl and alkylthiocarbonyl group, useful in treating or preventing an infectious disorder in humans or animals.
xxii) WO 01/42242 (Paget et. al.) discloses certain substituted 5-acetyl aminomethyl 3-substituted phenyloxazolidinones, the substitution being a bicyclic heterocyclic system, useful as antibacterial agents.
xxiii) WO 02/06278 (Mehta et. al) discloses certain substituted 3-phenyl oxazolidinones and to process for synthesis of the same, the said compounds useful as antibacterial agents, effective against a large number of human and veterinary pathogens, including Gram-positive bacteria and acid fast organisms such as Mycobacterium tuberculosis.
xxiv) WO 02/20515 (Madar et. al.) discloses heterocyclic phenyloxazolidinones, useful for treating bacterial infections. However, only a few of the disclosures described hereinbefore provide compounds that
can be used as antimycobacterials, while most of the others are silent about the antimycobacterial
activity of the disclosed compounds.
A need, therefore, exists for new compounds possessing potent antimycobacterial
properties for treatment of TB, which as mentioned hereinearlier is assuming alarming
proportions.
OBJECTS OF THE INVENTION
It is thus the basic object of the present invention to synthesize, identify and provide new
compounds belonging to the class of oxazolidinones, possessing potent antimycobacterial
properties especially for treatment of acid fast organisms such as Mycobacterium tuberculosis,
Mycobacterium avium-intracellular complex, M. fortuitum and M. kansai.
Another object is directed to providing antimycobacterial pharmaceutical composition
effective in inhibiting/treating the generation of mycobacterial conditions/cells including
Mycotacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M fortuitum and Mkansai.
6

Yet another object is directed to providing a method of treating/inhibiting mycobacterial cells/conditions involving the administrations of effective amount of the novel antimycobacterial compound and/or its salts /composition of the invention. SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention there is provided compound of formula (I) and its pharmaceutically acceptable salts thereof

wherein,
A, B = H, and/or F Ri is a group of formula

wherein,
Q is CH2-CH2, CH=CH, or C=C
Y is O,S or NR3
wherein,
R3 is Ci - C4 alkyl (straight, branched, unsaturated), cycloalkyl, COOH, COOR,, CHO, COCR4,
CN, aryl, heteroaryl
wherein,

R is an alkane of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6 carbon
atoms, and
Ar is an aromatic carbocycle represented by

7

wherein,
X is OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, Br, CI, F, or I,
M is-CHorN,and
Zis-CH,-NH,OorS
and wherein,
R3 and R4 are as described hereinbefore, and
R5 is H, or same as R4, and
R.2 is selected from the groups shown below, and the corressponding N-oxides thereof

Heteroaryl or Heterocycloalkyl wherein K is O, S, SO, S02, or CH2
According to another aspect of the invention there is provided a pharmaceutical
composition comprising:
i) atleast one of an antimycobacterially effective amounts of compound of formula I and
pharmaceutically acceptable salts there of; and ii) a pharmaceutically acceptable carrier.
According to yet another aspect of the present invention there is provided a method of inhibiting growth of mycobacterial cells such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M.kansai.,comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof.
8

According to yet another aspect of the present invention there is provided a method of treating mycobacterial conditions such as Mycobacterium tuberculosis, drug resistant Mycobacterium tuberculosis, Mycobacterium avium-intracellular complex, M. fortuitum and M kansai, comprising administering an antimycobacterially effective amount of the compound of formula I and/or pharmaceutically acceptable salts thereof.
According to another aspect, there is provided a process for the manufacture of the compound of formula I or its pharmaceutically acceptable salts comprising : coupling the amino fragments of compound of formula II with the carboxylic acid fragment of formula III.
The above disclosed compound of formula I its pharmaceutically acceptable salts thereof are found to have antimycobacterial properties and the same in admixture with pharmaceutically active additives, an be administrated orally or paranterally for treatement of mycobacterial conditions especially TB. DETAILED DESCRIPTION OF THE INVENTION
In the pharmaceutically active compound of formula (I) of this invention,

the definition of the symbols and groups A, B, Rt and R2 are as follows :
A is either hydrogen or fluorine,
B is either hydrogen or fluorine,
A and B together is hydrogen and fluorine,
When A is hydrogen, B is fluorine and vice-versa.
R1 represents a group of formula,

Q is either an alkyl group of two carbon atoms (CH2-CH2), an alkene group of two to carbon atoms (CH=CH), or an alkyne group of two carbon atoms (C=C)
9

Y can either be oxygen, sulfur or an amino function of formula NR3, wherein
R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be straight or
branched. Suitable alkyl groups are methyl, ethyl, n-propyl, n-butyl, iso-propyl, iso-butyl, tert-
butyl, ethylene, propylene, 1, butene, both the geometric isomers of 2-butene i. e.(cis)-2-butene
and (trans)-2-butene, and iso-butylene. or
R3 is a cycloalkyl group of 3-7 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl,
cyclohexyl and cycloheptyl, or
R3 is a carboxylic acid group (-COOH) or a carboxylic acid ester of formula-COOR4, wherein
R4 is H, an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of 3-6
carbon atoms.
R3 is further an aldehyde (-CHO), an acetyl group (-COCR4), wherein R4 is as mentioned
hereinbefore or R3 is a nitrile (CN), aryl or heteroaryl, wherein
Aryl is phenyl substituted with (0) or (1) of-F, -CI, -OCH3, -OH, -NH2, -CrC4 alkyl, -O-C(O)-
OCH3,-N02or-CN,and
Heteroaryl
or Ar is a five membered ring of formula
or Ar is a fused bicyclic phenyl or pyridine ring of formula
10
The group Ar is a substituted phenyl ring or a substituted pyridine ring of formula

wherein,
M is either CH or N; Z is -CH, -NH, O or S and R3 is as defined hereinbefore,
X is a group selected from OR4, NR4R5, N02, SR4, SOOR4, SOONR4R5, F, CI, Br or I, wherein
R4 is as defined hereinbefore, and
R5 is hydrogen or R4.
R2 is selected from the groups shown below, and the corresponding N-oxides thereof.

Heteroaryl or Heterocycloalkyl
wherein K is O, S, SO, S02, or CH2
The preferred novel compounds of formula (I) that form part of this invention, are as follows.
The following compounds 1 to 78( named as per IUPAC or CAS nomenclature) are preferred compounds of formula (I) of the invention.
1. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide.
2. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
3. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
4. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide.
5. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
11

6. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbutanamide.
7. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide.
8. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
9. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
10. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ]
- 4 - oxo - 4 - phenylbutanamide.
11. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methylphenyl) - 4- oxobutanamide.
12. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - (4 - methylphenyl) - 4- oxobutanamide.
13. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
14. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide.
15. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide.
16. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide.
17. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo-5-OXAZOlidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
18. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
19. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide.
20. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - (2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
21. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide.
22. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
23. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
12

24. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazohdinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
25. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazohdinyl methyl] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
26. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazohdinyl ] methyl
- 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide.
27. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
28. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl
- 4 - oxo - 4 -( 2 - thienyl)butanamide.
29. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide.
30. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] -4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide.
31. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide.
32. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide.
33. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N - oxide.
34. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
35. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - methoxyphenyl) - 4- oxobutanamide.
36. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - chlorophenyl) - 4- oxobutanamide.
37. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2,4 - dimethylphenyl) - 4- oxobutanamide.
38. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benztriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
39. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
40. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
41. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
13

42. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
43. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide.
44. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide.
45. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
46. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
47. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide.
48. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide.
49. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
50. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
51. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
52. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 -( 2 - thienyl)butanamide.
53. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
54. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
55. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - phenylbut - 2- enamide.
56. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - oxo- 4 - ( 4 - thiomethylphenyl )butanamide.
57. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - (2 - naphthyl) - 4 - oxobutanamide.
58. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide.
59. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidmylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl]
- 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
14

60. (S) - N -[ [ 3 - (3 - fluoro—4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
61. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl] - 4 - oxo - 4 - phenylbut - 2- enamide.
62. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
63. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4 - oxobutanamide.
64. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide.
65. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
66. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - oxo - 4 - (4 - thiomethylphenyl)butanamide.
67. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - ( 2 - naphthyl) - 4 - oxobutanamide.
68. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] -4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
69. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide.
70. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
71. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
72. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
73. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
74. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
75. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
76. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
77. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
15

78. (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 — oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide.
The respective N-oxides of the group R2 of the compounds of formula I listed above also form a novel aspect of the present invention.
The pharmaceutically active compounds of formula (I), the corresponding N-oxides of the group R2 and pharmaceutically acceptable salts thereof of this invention can be prepared by methods known to one skilled in the art.
Typically, compounds of formula (I), can be prepared by coupling of the amino fragment of formula (II)

Scheme-!
General method for synthesis of compounds of formula (I)

In a typical experiment, the amine compound of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinbefore is dissolved in a 1:1 mixture of tertahydrofuran and water or a 1:1 mixture of methylene chloride and water. To the solution is added the carboxylic acid compound of formula (III), followed by addition of 1-hydroxybenztriazole (HOBt). The resulting mixture is cooled to a temperature of 0-5° C to which l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 1.1 Eq.) is added and gradually allowed to warm to room temperature and agitated at this temperature for 24 hours. At the end of
17

the reaction, a solution of saturated aqueous sodium bicarbonate is added and the organic phase separated from the aqueous phase. Evaporation of the solvent and chromatography of the residue over silica gel affords compound of formula (I), generally as white solids.
The N-oxides of the group R2 of compound of formula (I) thus obtained are preferably prepared by addition of m-chloro perbenzoic acid (m-CPBA) to a cooled solution of the compound of formula (I) in a chlorinated hydrocarbon solvent such as methylene chloride and ethylene chloride and thereafter agitating the reaction mixture at room temperature for 12-15 hours. Evaporation of the solvent under reduced pressure, followed by chromatography of the residue over silica gel affords the corresponding N-oxides in high purity.
The N-oxides thus prepared, while retaining most of the antimycobacterial activity of the corresponding deoxo compound exhibit exceedingly high water solubility over the deoxo analogue, thereby helping in manufacture of suitable iv formulations, which forms an important aspect of this invention.
The starting materials required for synthesis of compound of formula (I), thus involve the amine compound of formula II and the carboxylic acid compound of formula III.
The amine compound of formula II can be selected from i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, vi) (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, and viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 -
oxazolidinyl] methyl amine.
18

The carboxylic acid compound of formula III can be selected from 4-(2-Naphthyl)-4-
oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic
acid, 4-oxo-4-(2'methylpropyl)phenylbutanoic acid, 4-Oxo-4-
(2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 - oxobutanoic acid,4 - (2,4 -
dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4-
chlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid,
4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 - phenyl - but - 2 - ynoic acid.
20

Thus, the starting amines of formula (II), wherein the groups A, B, and R2 have the same meanings as defined hereinearlier are prepared as per the method disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33, 2569-2578; C. Wang et. al., Tetrahedron, 1989, 45, 1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO 95/25106 and WO 97,21708. The method is essentially summarized in Scheme-II.

In a typical method, morpholine, thiomorpholine, piperidine, 4-benzyl piperazine, pyrrolidine, 1,2,4-triazine, 12,3-benzotriazine, benzyl amine, a heterocycloalkyl or a heteroaryl moiety etc., each one of which corresponds to the group R2 defined hereinbefore is reacted with 3,4-difluoro nitrobenzene in the presence of a base and a solvent to give the corresponding derivative in which the fluorine atom at 4-position is substituted by the group R2. The nitro group in the compound thus obtained is reduced to amino group, which is thereafter protected by a suitable protective group. Reaction of the N-protected compound thus obtained with (R)-glycidyl butyrate in the presence of a strong base like n-butyl lithium leads to formation of the 5-hydroxymethyl oxazolidinone ring. The hydroxy group in the compound thus obtained is converted to sulfonyl derivative, for e.g. a methanesulfonyloxy (mesyl) or a p-toluenesulfonyloxy (tosyl) derivative by reaction with methanesulfonyl chloride or p-toluenesulfonyl chloride respectively. Reaction of the respective mesyl or tosyl derivative with sodium azide gives the corresponding azide, which is converted to the amine compound of formula (II) by standard methods, for e.g. by reaction with a triaryl/trialkyl phosphine, followed by hydrolysis.
The starting carboxylic acid fragments of formula (III), wherein the group Ar has the same meaning as defined hereinearlier are prepared as per the method disclosed in Org. Reactions, 1949, 5, 229-289; Quart. Rev. Chem. Soc, 1954, 8, 355-379; Chem. Rev., 1955, 55, 229-281, and J. Am. Chem. Soc, 1947, 69, 1784-1786. The method is essentially summarized in Scheme-HI.
Scheme-Ill General method for synthesis ofalkane and alkene carboxylic acid s of formula (HI)

In a typical method, the aromatic compound Ar-H, wherein Ar is as defined hereinbefore is reacted with succinic anhydride in the presence of a Lewis acid, such as anhydrous aluminium chloride and in the presence of an anhydrous solvent and the mixture heated to 100° C to give the carboxylic acid derivatives of formula (HI), wherein Q is alkyl of 1-4 carbon atoms.
23

Similarly, compounds of formula (III), wherein Q is an alkene (CH=CH) are prepared by reaction of the aromatic compound Ar-H, wherein Ar is as defined hereinbefore with maleic anhydride under the same conditions mentioned hereinbefore.
Compounds of formula (III), wherein Q is an alkyne (C=C) are prepared by reaction of propiolic acid ester with an aldehyde of formula Ar-CHO in the presence of butyl lithium and in the presence of an aprotic solvent such as THF at -78° C to give the corresponding secondary alcohol, which is oxidized to the keto derivative using manganese dioxide as the oxidizing agent. Saponification gives the carboxylic acid derivative of formula (ID) [ US 4,929,741 (A. Fischili et. al.) ] The synthesis is summarized in Scheme-IV.

P = any protective group
The synthesis of compound of formula (I) of this invention and the synthesis of the respective starting material amines of formula (II) and the carboxylic acids of formula (III) are further described herein in detail.
SYNTHESIS OF THE STARTING AMINES OF FORMULA OD
The amines were prepared as per the chemistry summarized in the Scheme-H and as per the methods disclosed by W. A. Gregory et. al., J. Med Chem., 1989, 32, 1673-1681 and 1990, 33,2569-2578; C. Wang et. al., Tetrahedron, 1989, 45,1323-1326; Britelli et. al., J. Med. Chem., 1992, 35, 1156 and Bioorg. Med. Chem. Lett., 1999, 9, 2679-2684; M. R. Barbachyn et. al., J. Med. Chem., 1996, 39, 680-685; M. J. Genin et. al., J. Med. Chem., 2000, 43, 953-970; WO
24

95/25106 and WO 97,21708. Commercially available raw materials and known techniques were utilized for the synthesis.
The optically pure amines as such were obtained by using optically active intermediates or resolution of racemic mixtures by a suitable reagent. The preferred enantiomer is (S), at the chiral centre on the oxazolidinone ring.
Example 1 General Method for Preparation of the Amines (II)
The oxazolidinone azides of general formula (8), given in Scheme-II (1.0 eq) were dissolved in dry THF (10 times by volume ) and treated with triphenyl phosphine (1.5 eq.) at room temp. The resulting solution was stirred for 6hrs at room temp. Water [2 eq. of (8)] was added and the solution heated for 6hrs at 55 - 60° C. The solvent was evaporated and the residue chromatographed on a column of silica gel (100 -200 mesh) and eluted initially with ethyl acetate and then with chloroform : methanol (4:1) to give the the amines (II) as white solids.
The following amines i) to viii) of formula I were prepared by this general method, viz.
i) (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, ii) (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, iii) (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, iv) (S) - N -[3 - ( 3 - fluoro - 4 - benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, v) (S) - N -[3 - (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl
amine, vi) (S) - N -[3 - (3 - fluoro — 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, vii) (S) - N -[3 - (3 - fluoro - 4 - benzotriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, and
viii) (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 -
oxazolidinyl] methyl amine.
SYNTHESIS OF THE STARTING CARBOXYLIC ACIDS OF FORMULA (HP
Example 2 4-(2-Naphthyl)-4-oxobutanoic acid
Naphthalene (5.0gm, 0.039moles) and succinic anhydride (4.68gm, 0.0468 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (11.44g, 0.0858 moles) was added at
25

room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 25 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid. Subsequent column chromatography gave a buff coloured solid. Subsequent chromatography gave 3.7 gm (41%) the title compound, mp 173-174° C.
'H NMR (CDCI3, 5) : 8.40 (s,lH), 7.7 - 8.0 ( m, 4H), 7.4 - 7.6 (m,2H), 3.33 (t,2H), 2.77 (t,2H + 1H).
The filterate was concentrated to give 5.8 gm of a mixture of 4-(2-naphthyl)-4-oxobutanoic and 4-(l-naphthyl)-4-oxobutanoic acid.
Example 3 4- Oxo-4-(2- ThienylJbutanoicacid
Thiophene (5.0gm, 0.059moles) and succinic anhydride (7.13gm, 0.0713 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (17.43gm, 0.131 moles) was added at room temperature and the resulting mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 30 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (50 ml). The solid was dried at room temp to give 9.8 gm (89%0 of the title compound, mp 103 - 107° C.
!H NMR (CDCI3, 8) : 7.69 (dd, 1H), 7.58 (dd, 1H), 7.07 (dd,lH), 3.9 (bs, 1H), 3.23 (t, 2H), 2.74 (t,2H).
Example 4 4- Oxo-4-(4-thiomethyl)phenylbutanoic acid
Thiophenol methyl ether (8.0gm, 0.0645moles) and succinic anhydride (7.75gm, 0.0774 moles) were taken up in dichloroethane (80 ml). Aluminium chloride (18.90gm, 0.1419 moles) was added at room temperature. The resulting mixture stirred for 0.5hr and then heated at 85° C for lhr. The reaction mixture was cooled to room temperature, diluted with 40 ml of 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the separated solid was filtered under suction, washed with water and dilute hydrochloric acid (80 ml). The solid was dried at room temp to give 6.9 gm (48%) of the title compound, mp 151 -154° C. *H NMR (CDCI3, 5) : 7.82 (d,2H), 7.20 (d, 2H), 4.2 (bs, 1H), 3.21 (t, 2H), 2.73(t, 2H),2.45 (s,3H).
26

Example 5 4 - oxo -4- (2'methylpropyl)phenylbutanoic acid
2'methylpropylbenzene (5.0m, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles), were taken up in dichloroethane (50 ml). Aluminium chloride (10.90g, 0.0821 moles ) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 ml of a 1:1 mixture of water and Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.7 gm (99%) of the title compound as a solid, mp 102 - 105° C.
!H - NMR (CDC13, 8) : 7.83 (d,2H), 7.17(d,2H), 3.24(t,2H), 2.74(t, 2H), 2.46 (d, 2H), 1.80 (pent., 1H).
Example 6 4 - Oxo - 4 - (2',2'dimethylethyl)phenylbutanoic acid
2',2'dimethylethylbenzene (5.0gm, 0.0373moles) and succinic anhydride (4.5gm, 0.0448 moles) were taken up in dichloroethane (50 ml). Aluminium chloride (10.90gm, 0.0821 moles) was added at room temperature and the mixture heated under reflux for lhr with stirring. The reaction mixture was cooled to room temperature, diluted with 40 m of a 1:1 mixture of water Cone, hydrochloric acid. After stirring for 10 min the reaction mixture was extracted with ethyl acetate (25ml). The ethyl acetate layer was dried and concentrated to give 8.5 gm (97%) of the title compound as a solid, mp 103 — 107° C. !H-NMR (CDCI3,8) : 7.94(d,2H), 7.50 (d, 2H), 3.29 (t,2H), 2.82 (t,2H), 1.36 (s,9H).
Example 7 Using the appropriate aromatic compound (Ar-H) and succinic anhydride and following exactly the method described in Examples 2-6 the following carboxylic acids can be prepared, viz.
i) 4 -(4 -methylphenyl)- 4 - oxobutanoic acid,
ii) 4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid, iii) 4 - (4 - methoxyphenyl)- 4 - oxobutanoic acid, iv) 4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid, v) 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, vi) 4 - (2,4 -difluorophenyl) - 4 - oxobutanoic acid, vii) 4 -{2- Naphthyl)- 4 - oxobutanoic acid, viii) 4 - (4 -acetamidophenyl) -4 - oxobutanoic acid, ix) (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and x) 4 - oxo - 4 - phenyl - but - 2 - ynoic acid.
27

SYNTHESIS OF THE COMPOUNDS OF FORMULA (D
Example 7
Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - J -
oxazolidinyl ] methyl] — 4-(4- naphthyl) -4- oxobutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 dichloromethane-water mixture (10 ml). To this was added 4 -( 2 - naphthyl- 4 - oxobutanoic acid (0.154gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) the resulting mixture was cooled to 0° C. l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added the resulting mixture was allowed to warm to room temperature and then stirred for 24hr. Saturated aqueous sodium bicarbonate solution (2ml) was added to the reaction mixture, stirred for 15 min and then the organic layer separated and the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.22 gm, 64%) as a white solid. MS (M+l) = 506 m/z
*H NMR (CDC13, 5) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, 1H ), 7.01(dd,lH ), 6.74 (t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, 1H), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91 (m,4H), 2.60(t, 2H).
Example 8
Preparation of (S) -N-[[3- (3-fluoro-4-morpholinylphenyl) -2-oxo-5-
oxazolidinyl ] methyl] -4- oxo -4-(2- thienyl)butanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml) . To this was added 4 - oxo - 4 (2 - thienyl)butanoic acid (0.125gm, 0. 00068 moles) and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the resulting mixture was allowed to warm to room temp and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated sodium bicarbonate was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separatedand the solvent evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20gm). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.175 gm, 56%) as a white solid
MS (M+1) = 462 m/z
28

lH NMR (CDC13, 8) : 7.63(d,lH ), 7.55 (dd,lH ), 7.35(dd,lH), 7.04(t, like dd, 2H), 6.83(t,lH), 6.30 (t,lH), 4.69(m,lH), 3.93 (t, 1H), 3.6- 3.8 (m, 3H),3.80 (m,4H), 3.61(dd, 2H), 3.21(dd,2H),2.97 (m,4H),2.55(t, 2H).
Example 9
Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -
oxazolidinyl ] methyl ] - 4 - [4 - ( V- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 -oxo - 5 -oxazolidinyl] methyl amine(0.200gm, 0.00068 moles) was taken up in 1:1 THF - water mixture (20 ml). To this was added 4 - [ 4(2'-methylpropylphenyl)]- 4 - oxobutanoic acid (0.158gm, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles). The resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142gm, 0.00074 moles) was added and the mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated, and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give the title compound (0.210gm, 60%) as a white solid.
MS(M=l) = 512m/z
'H NMR (CDC13, 8) : 7.73(d,2H ), 7.52 (dd,lH ), 7.28(m,lH ),7.15(d,2H ), 7.05 (d,lH), 6.39 (t,lH), 4.75(m,lH), 3.91 (m, 4H), 3.5- 3.9 (m, 4H), 3.28 (dd, 2H), 3.16 (m,4H),2.54 (t, 2H), 2.45 (d, 2H), 1.82 (pent., 1H), 2.60 (t, 2H).
Example 10
Preparation of(S) -N-[ [3 - (3 -fluoro -4- morpholinylphenyl) - 2 -oxo - J -
oxazolidinyl J methyl J -4- oxo - 4 -(4- thiomethyl) phenylbutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl amine (0.200gm, 0.00068 moles) was taken up in 1:1 THF -water mixture (20 ml). To this was added 4 - (4-methlythiophenyl) - 4 - oxobutanoic acid (0.152g, 0. 00068 moles and HOBt (0.091gm, 0.00068 moles) and the resulting mixture was cooled to 0° C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.142g, 0.00074 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated, 15 ml of saturated aqueous sodium bicarbonate was added to, stirred for 15 min and then extracted with ethyl acetate. The ethyl acetate layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g). The column was eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The
29

combined fractions were concentrated to give the title compound (0.270 gm, 79%) as a white solid.
MS (M+l) = 502 m/z
JH NMR (CDC13, 5) : 7.70(d,2H ), 7.37 (dd,lH ), 7.14(d,2H ), 7.00 (dd,lH), 6.79(t,lH), 6.38 (t,lH), 4.71(m,lH), 3.86(t,lH),3.5- 3.9 (m, 4H), 3.81 (m, 4H), 3.22 (dd, 2H), 2.96 (m,4H),2.53 (t, 2H), 2.45(s,3H).
Example 11
Preparation of:. (S) - N-[[3 - (3 -fluoro -4- morphottnylphenyl) — 2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) - 4 - oxobutanamide.
(S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine(0.100gm, 0.00034 moles) was taken up in 1:1 THF-water mixture (20 ml) . To this was added 4 - (4- chlorophenyl) - 4 - oxobutanoic acid(0.072g, 0.00034 moles and HOBt (0.046g, 0.00034 moles) .The resulting mixture was cooled to 0°C, and then l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.071gm, 0.00037 moles) was added. The resulting mixture was allowed to warm to room temperature and then stirred for 24hr. The reaction mixture was concentrated and 2 ml of saturated aqueous sodium bicarbonate solution was added, stirred for 15 min and then extracted with dichloromethane. The organic layer was separated and evaporated off. The residue was chromatographed over silica gel (100 - 200 mesh, 20g) and eluted with mixture of ethyl acetate: hexane, and finally with ethyl acetate. The combined fractions were concentrated to give (0.070gm, 42%) of the title compound as a white solid.
MS (M+l) = 490 m/z
JH NMR (CDCI3, 8) : 7.72(d,2H ),7.37 (dd,lH ),7.31(d,2H ), 6.98 (dd,lH),6.79 (t,lH), 6.28
(t,lH), 4.69(m,lH), 3.83 (t, 1H), 3.81 (m, 4H), 3.4- 3.m (m, 3H), 3.21 (dd, 2H), 2.97 (m,4H),2.54
(t,2H).
Example 12
Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -
oxazolidinyl ] methyl ] - 4 - ( 2 -naphthyl) - 4 - oxobutanamide - N - oxide.
To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -
2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (2 -naphthyl) - 4 - oxobutanamide (0.950gm, 0.0019
moles) in dichloromethane (150 ml) was added 60% m -CPBA (0.550g, 0.0032 moles) and the
resulting solution stirred at room temperature for 12hr. The solvent was evaporated under
reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The
column was eluted with ethyl acetate (200 ml), followed by a mixture of chloroform : methanol
30

(4:1,600 ml).Concentration the combined fractions gave the title N-oxide (0.891g, 82% ) as a
white solid.
!H NMR (CDCI3, 8) : 8.59(t,lH ), 8.36(s,lH),7.7-7.9 (m,5H), 7.2 -7.5 (m,2H),7.08 (dd,lH),
6.60(t,lH), 4.76(m,lH), 4.61(bt,2H), 3.5 - 4.3 (m, 9H), 3.42 (dd, 2H), 2.83 (bdd,2H), 2.61 (bt,
2H).
Example 13
Preparation of (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide - N - oxide. To a cooled solution (0 - 5° C) of (S) - N -[[3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - oxo - 4 - (2 - thienyl)butanamide (0.850gm, 0.0017moles) in dichloromethane (120 ml) was added 60% m -CPBA (0.550g,0.0032 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g). The column was eluted with ethyl acetate (200ml) followed by a mixture of chloroform : methanol (4:1,600 ml).Concentration of the combined fractions gave the tile N-oxide (0.790g, 90%) as a white solid.
1HNMR( CDCI3,5) : 8.63(t,lH), 7.77(dd,lH), 7.65 (d, 1H), 7.56 (d, 1H), 7.09 (dd, 1H),7.04 (dd,lH), 6.45(t,lH), 4.68(m,lH), 4.65(bt,2H), 4.22 (dt,2H), 3.89(t,lH), 3.5 - 3.9 (m, 5H), 3.22 (dd, 2H), 3.00 (bd,2H), 2.54 (t, 2H).
Example 14 Preparation of(S) - N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 -oxazolidinyl J methyl] -4-(4- chlorophenyl) -4- oxobutanamide -N- oxide. To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide, (1.150gm, 0.0023 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.725gm, 0.0040 moles) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1,600 ml). Concentration of the combined fractions gave the title N-oxide (0.950g, 80%) as a white solid.
'HNMRtCDCk 8) : 8.61(t,lH ), 7.76(d,2H), 7.72 (dd, 1H), 7.34 (d, 2H), 7.10 (dd, 1H), 6.46(t,lH), 4.70(m,lH), 4.64(bt,2H), 4.16 (dt,2H), 3.94(t,lH), 3.5 - 3.9 (m, 5H), 3.24 (dd, 2H), 2.97 (bd,2H), 2.55 (t, 2H).
31

Example 15 Preparation of(S) -N-[[3 -(3 -fluoro -4- morpholinylphenyl) -2- oxo -5-oxazolidinyl ] methyl] -4-/4-(2'- methyl - 4 -propylphenyl) -4 — oxobutanamide -N-
oxide.
To a cooled solution (0 - 5° C) of (S) - N -[[ 3 - (3 - fluoro - 4 - morpholinylphenyl) -2 - oxo - 5 - oxazolidinyl] methyl] - 4 - [4 - (2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide (1.05gm, 0.0020 moles) in dichloromethane (150 ml) was added 60% m -CPBA ( 0.600gm) and the resulting solution stirred at room temperature for 12hr. The solvent was evaporated under reduced pressure and the residue chromatographed over silica gel (100 -200 mesh, 40g ). The column was eluted with ethyl acetate (200 ml) followed by a mixture of chloroform : methanol (4:1 , 600 ml). Concentration of the combined fractions gave the title N-oxide (0.891gm, 82%) as a white solid.
JH NMR (CDC13, 5) : 8.62(t,lH ), 7.77(dd,lH), 7.75 (d, 2H), 7.14 (d, 2H), 7.12 (dd, 1H), 6.44(t,lH), 4.75(m,lH), 4.64(bt,2H), 4.20 (dt,2H), 3.95(t,lH), 3.91 (t,lH) 3.5-3.9 (m, 4H), 3.26 (dd, 2H), 2.99(bd,2H), 2.57 (t, 2H),2.44(d,2H), 0.83(d,6H).
Example 16 Preparation of (S)-N-ff3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4-
methylphenyl)-4-thiooxobutanamide
To a solution of (S)-n- of (S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methyl]-4-(4-methylphenyl)-4-oxo-butanamide (0.1 Ogm, 0.00021 moles) in dry THF (5ml) was added Lawessons Reagent (0.052gm, 0.000128 moles) and the resulting solution heated under reflux for 8 hr. The reaction mixture was cooled to room temperature and to this was added saturated aqueous sodium carbonate solution (3ml) and then extracted with ethyl acetate. The solvent was evaporated off and the residue chromatographed over silica gel and eluted with a mixture of ethyl acetate-hexane to give the title compound (0.023 gm, 23%) as a white solid, mp 149-151° C.
lH NMR (CDCI3,5) : 8.60 (m, 1H), 7.68 (d, 2H), 7.34 (dd, 1H), 7.14 (d, 2H), 6.96 (dd, 1H), 6.81 (t, 1H), 4.90 (m, 1H), 4.20-4.40 (m, 1H), 3.80-4.0 (m, 4H), 3.50 (m, 2H), 2.90-3.00 (m, 6H).
Example 17 Using the appropriate amine compound (II) and the carboxylic acid (HI) and following exactly the method described in Examples 7-16 the following carboxylic acids can be prepared, viz.
(S) - N-[ [ 3 - (3-fluoro — 4- morpholinylphenyl) -2- oxo — 5- oxazolidinyl J methyl] — 4-(4- methylphenyl) -4- oxobutanamide.
32

'H NMR (CDCI3, 5) : 7.78 (d, 2H ), 7.44 ( d, IH ), 7.22 ( d,2H ), 7.09 ( d, IH ), 6.88 ( t, IH ), 6.41(t, IH), 4.76 (m, IH ), 3.6 - 4.1 (m, 4H ), 3.86 ( m, 4H ), 3.31 ( dd, 2H ), 2.61 (t, 2H ), 2.40 (s.3H).
(S) -N-[[ 3-(3 -fluoro -4 - benzylpiperazinyl) phenyl] -2- oxo - 5 - oxazolidinyl] methy ] -4-oxo -4-phenylbutanamide.
lH -NMR (CDC13, 5) : 7-88 ( d,2H ), 7.61 (dd, IH), 7.38 ( m, 5H ), 7.2 - 7.4 (m, 5H), 6.88 (t, IH ), 6.55 (t, IH ), 4.77 ( m, IH), 3.94 (t, IH), 3.5 - 3.7 (m, 3H ), 3.71 ( s, 2H ), 3.34 (dd, 2H ), 3.12 (m, 4H),3.12 (m, 4H ), 2.61 (t, 2H ).
(S) - N-f]3 - ( 3 -fluoro - 4 - [methylbenzylamin]phenyl) - 2 - oxo -5 - oxazolidiny] methy ]-4-(4- methyl phenyl) -4- oxobutanamide.
*H NMR (CDCI3, 8) : 7.90 ( d, 2H ), 7.52 ( dd, IH ), 7.2 - 7.5 ( m, 8H ), 7.05 ( d, IH ), 6.84 (t, IH ), 6.50 (t, IH ), 4.75 (m, IH ), 4.48 (s, 2H ), 3.95 (t, IH), 3.6 - 4.1( m,3H ), 3.64 ( dd, 2H ), 2.71 (s,3H), 2.62 (t,2H).
(S)-N-[[3-(3-fluoro-4- benzotriazolylpheny)-2-oxo-5-oxazolidinyl]methy]-4-oxo - 4 -phenylbutanamide.
!H NMR ( CDCI3, 5) : 8.16 ( d,lH), 7.84 (d, 2H), 7.66 (t, IH), 7.2 -7.6 (m, 8H), 6.46 (t, IH ), 4.90 (m, IH), 3.98 (t,lH), 3.9 - 4.0 (m, 2H ), 3.65 (m, IH ), 3.39 (ddd, 2H ), 2.65 ( ddd, 2H). (S) -N-[[3-(3-fluoro-4- pyrrolidinylphen) -2-oxo-5- oxazolidinyl]methyl]-4-oxo - 4 -phenylbutanamide.
!H NMR (CDCI3, 8) : 7.90 (d,2H ), 7.52 (dd, IH ), 7.44 (d, 2H ), (dd, IH ), 7.04 (dd, IH), 6.65 (t, IH), 6.43 (t, IH), 4.74 (m,lh), 3.93 (t,lH), 3.77 (t,lH), 3.6 3,8 (m, 2H), 3.33 (m, 6H ), 2.63 (t, 3H), 1.94 (m,4H).
(S)-N-[[3-(3-fluoro-4- benzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methy]-4-(4- methlyphenyl) - 4- oxobutanamide.
!HNMR (CDCU, 8) : 8.16 (d, IH ), 7.3 - 7.9( m,7H), 7.78 (d,2H ), 7.21(d,lH), 6.54(t, IH), 4.89 ( m, IH), 3.8 -42 (m, 3H ), 3.4 - 3.7 (m, 3H ), 2.63 (dd, 2H ), 2.23 (s, 3H ). (S)-N-][3-(3 -fluoro - 4 - thiomorpholinylphenyl) -2 — oxo - 5 - oxazolidinyl] methyl] -4- oxo- 4 -phenylbutanamide.
!H NMR (CDCI3, 8) : 7.89 (d, 2H ), 7.39 - 7.60 ( m, 4H ), 7.11 (dd, IH ), 6.90 (t, IH), 6.39 ( t,lH ), 4.76 (m,lH ), 3.94 (t,lH ), 3.80 (t, IH ), 3.6 - 3.7 ( m, 2H ), 3.36 ( dd, 2H ), 3.28 ( m,4H), 2.80 ( m,4H ), 2.62 (t, 2H).
(S) — N-[[3 - (3 -fluoro - 4 - benzylpiperazinyl) phenyl] — 2 — oxo — 5 - oxazolidinyl] methyl]- 4-(4- methylphenyl) -4- oxobutanamide.
33

*H NMR (CDCI3, 5) : 7.81 ( d, 2H), 7.2 - 7.5 ( m, 8H ), 7.08 (dd, IH ), 6,89 (t, IH ), 6.39 (t, IH
), 4,78 ( m, IH ), 3.95( t, IH), 3.79 (t, IH), 3.6 - 3.7 (ni, 2H ), 3.61(s, 2H), 3.31 ( m,2H), 3.09
(m,4H), 2.65 (m,6H), 2.41 (s, 3H).
(S)-N-[[3-(3-fluoro-4- piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl]-4-
oxo - 4 - phenylbutanamide.
!H NMR (CDCI3, 8) : 7.90(d,2H ),7.60 (dd,lH ),7.45(d,2H ), 7.39 (dd,lH), 7.10 (dd,lH), 6.90
(t,lH), 6.55 (t,lH), 4.78(m,lH), 3.95 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.35 (m, 2H), 3.00
(m,4H0,2.63 (t, 2H), 1.9-1.6 (m,6H).
(S)-N-[[3- (3 -fluoro-4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4-(4
- methylphenyl) - 4- oxobutanamide.
JH NMR (CDCI3, 5) : 7.79(d,2H ),7.40 (dd,lH ),7.23(d,2H ), 7.09 (dd,lH), 6.91 (t,lH), 6.40
(t,lH), 4.77(m,lH), 3.98 (t, IH), 3.80 (t, IH), 3.4- 3.7 (m, 2H), 3.30(t, 2H), 2.98 (m,4H), 2.62 (t,
2H),2.41(s,3H), 1.6-1.9 (m,6H).
(S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5- oxazolidinyl] methyl]- 4
-(4- methylphenyl) - 4- oxobutanamide.
'H NMR (CDCI3, 8) : 7.80(d,2H ),7.32 (dd,lH ),7.21(d,2H ), 7.01 (dd,lH), 6.60 (t,lH), 6.40
(t,lH), 4.75(m,lH),4.12(m,lH) 3.94 (t, IH), 3.75 (t, IH), 3.4- 3.6 (m, 2H), 3.34 (m, 6H), 2.61 (t,
2H),2.40(s,3H), 1.9(m,4H).
(S)-N-[[3-(3-fluoro-4-morpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4
-(4- methoxyphenyl) -4- oxobutanamide.
lU NMR (CDCI3, 8) : 7.79(d,2H ),7.36 (dd,lH ), 7.00 (dd,lH), 6.82 (d,2H), 6.80(t,lH), 6.38
(t,lH), 4.69(m,lH), 3.80 (s, 3H), 3.78 (m, 4H), 3.4- 4.0 (m, 4H), 3.20 (dt, 2H), 2.97 (m,4H),2.55
(dt,2H).
(S) -N-[[3-(3 -fluoro -4- morpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-
(2 -naphthyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) : 8.35(s,lH ),7.83(m, 4H), 7.50(m,2H),7.38 (dd, IH ), 7.01(dd,lH ), 6.74
(t,lH), 6.41 (t,lH), 4.71(m,lH), 3.88 (t, IH), 3.77 (m, 4H), 3.5- 3.8 (m, 3H), 3.40 (dd, 2H), 2.91
(m,4H), 2.60(t, 2H).
((S) - N -[[ 3 - (3 -fluoro -4- morpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-
(2, 4-difluorophenyl) -4-oxobutanamide.
!H NMR (CDCI3, 8) : 7.73(ddd,2H ), 7.47 (dd,lH ), 7.01(dd,lH ),6.7 - 6.9(m,3H ), 6.30 (t,lH),
4.75(m,lH), 3.89 (m, 4H), 3.5- 3.9 (m, 4H), 3.20 (m, 2H), 3.09(m,4H), 2.52 (t, 2H).
(S)-N -[[ 3-(3 -fluoro -4- morpholinylphenyl) -2- oxo -5— oxazolidinyl] methyl] - 4
-[4- (2s',2'- dimethyl- 4 - ethylphenyl) -4- oxobutanamide.
34

!H NMR (CDC13, 8) : 7.75(d,2H ), 7.37 (d,2H ), 7.35(dd,lH ), 7.05 (dd,lH), 6.82(t,lH), 6.37
(t,lH), 4.71(m,lH), 3.5- 3.9 (m, 4H), 3.80 (m, 4H), 3.25 (dt, 2H), 2.97 (m,4H),2.54 (t, 2H),
1.26(s,9H).
(S) -N-ff 3 - (3 -fluoro - 4 -fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl] -4-(4- methoxyphenyl) -4- oxobutanamide.
lU NMR (CDC13, 8) : 7.76(d,2H ), 7.37 (dd,lH ), 7.16(m,5H ), 6.93 (dd,lH), 6.79(d,2H),6.74 (
t,lH), 6.37 (t,lH), 4.66(m,lH),4.14 (s,2H), 3.84(t,lH), 3.74 (s,3H), 3.4- 3.8 (m, 3H), 3.18 (dd,
2H), 2.62(s,3H),2.5 l(t, 2H).
(S) -N-ff 3 - (3 -fluoro - 4 - fmethylbenzylaminojphenyl) - 2 - oxo - 5 - oxazolidinyl]
methy] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide.
'H NMR (CDCU, 8) : 7.77(d,2H ), 7.37 (dd +d,3H ), 7.19 -7.22(m, 3H), 6.98 (dd,lH),
6.77(t,lH), 6.31 (t,lH), 4.69(m,lH), 4.17(s,2H), 3.89(t,lH)„3.72 (dd,lH), 3.5- 3.6 (m, 2H), 3.25
(dd, 2H), 2.64 (s,3H),2.55 (t, 2H), 1.25(s,9H).
(S) -N-ff 3 -(3 -fluoro - 4 -[methylbenzylamino]phenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl] -4- (2,4 - dimethylphenyl) -4- oxobutanamide.
lU NMR (CDCI3, 8) : 7.65(d,lH ), 7.46 (dd,lH ), 7.32(m,5H ), 7.04(m,3H), 6.95(t,lH), 6.36
(t,lH), 4.78(m,lH), 4.27(s,2H), 3.97(t,lH),3.6- 3.8 (m, 2H), 3.81 (t, IH), 3.27 (dd, 2H), 2.77
(s,3H),2.61 (t, 2H), 2.44(s,3H), 2.35 (s, 3H).
(S)-N -[[ 3-(3 -fluoro -4- tnorpholinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] - 4
- (2,4 - dimethylphenyl) -4- oxobutanamide.
'H NMR (CDCU, 8) : 7.652(d,lH ), 7.42 (dd,lH ), 7.0- 7.1(m,3H), 6.86(t,lH), 6.38 (t,lH),
4.79(m,lH), 3.95(t,lH),3.5- 3.9 (m, 2H), 3.87 (m, 4H), 3.25(dd, 2H), 3.02 (m,4H), 2.59 (t, 2H),
2.41(s,3H), 2.34 (s, 3H).
^ -N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) —2 — oxo -5 — oxazolidinyl] methyl] — 4 —
(2,4 - dimethylphenyl) - 4 - oxobutanamide.
JH NMR (CDCI3, 8) : 7.62(d,lH ), 7.31 (dd,lH ), 7.03(s,+dd, 3H ), 6.60(t,lH), 6.36 (t,lH),
4.74(m,lH), 3.94(t,lH), 3.76 (dd, lH),3.67(m, 2H), 3.30 (m, 4H), 3.24 (dt, 2H), 2.60 (t, 2H),
2.44(s,3H), 2.34 (s, 3H).1.94 (m,2H).
(S) -N-ff 3-(3-fluoro-4- benztriazolylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4-
(2,4- dimethylphenyl) -4-oxobutanamide.
!H NMR (CDCI3, 8) : 8.15(d,lH ), 7.80 (dd,lH ), 7.3 -7.7(m,6H ), 7.02(d,2H), 6.39 (t,lH),
4.87(m,lH), 4.07(t,lH), 3.96(t,lH), 3.89 (dq, IH), 3.75(dt,lH), 3.38 (qt, 2H), 2.62 (m, 2H),
2.39(s,3H), 2.26 (s, 3H).
(S) - N-ff 3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-
oxo -4-(2- thienyl)butanamide.
35

*H NMR (CDC13, 8) : 7.71(d,lH ), 7.63 (d,lH ), 7.31(dd,lH ), 7.11 (t, lH),7.05(dd,lH), 6.68(m,lH), 6.38 (t,lH), 4.74(m,lH), 3.95(t,lH), 3.77 (t, 1H),3.6- 3.7 (m, 2H), 3.36 (m, 4H), 3.28 (t, 2H), 2.63 (t, 2H), 1.96 (m,2H). (S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo - J - oxazolidinyl] methyl] - 4
- oxo -4-(2- thienyl)butanamide.
!H NMR (CDC13, 8) : 8.08(d,lH), 7.77(dd,lH ), 7.3 - 7.7(m,7H ), 7.02(t,lH), 6.45 (t,lH),
4.81(m,lH), 4.00(t,lH),3.7- 4.0 (m, 2H), 3.57 (dt, 1H), 3.25 (m, 2H), 2.55 (m,2H).
(3? -N-[[3-(3-fluoro-4- morpholinylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4-
oxo - 4 -phenylbut - 2- enamide.
JH NMR (CDCI3, 8) :7.92 (d,lH), 7.84 (,d,lH), 7.2 - 7.6 (m, 6H), 6.98 - 7.1 (m, 3H), 4.38(m,
1H), 3.5 - 4.1 (m, 4H), 3.84 (m, 4H), 3.03 (m, 4H).
(S) -N-[[3-(3 -fluoro-4- piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl]-4-(4
- methoxyphenyl) - 4- oxobutanamide.
'HNMR^MSOde, 8) : 8.25 (t, 1H), 7.79 (d, 2H), 7.38 (dd, 1H), 7.71 (dd, 1H), 6.95 (t,lH), 6.93
(d, 2H + 1H), 4.65 (m,lH), 3.75 (s,3H), 3.99 (t, 1H), 3.64 (dd, 1H), 3.06 (t, 2H), 2.81(m,4H), 1.3
-1.6(m.6H).
(S) -N-[[3-(3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(4
- chlorophenyl) - 4- oxobutanamide.
lH NMR (CDCI3, 8) : 7.73(d,2H ), 7.33 (d,2H ), 7.2 - 7.8 (m, 2H),6.96(dd,lH), 6.34 (t,lH), 4.72(m,lH), 3.84(t,lH), 3.5- 3.8 (m, 3H), 3.21 (dd, 2H), 2.98 (m, 4H),2.54(t,2H), 1.5 - 1.7 (m,6H).
(S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5-oxazolidinyl]methyl] -4-(2,4 - dimethylphenyl) - 4- oxobutanamide.
'H NMR (CDCI3, 8) : 7.55(d,2H ), 7.4 (m,lH ), 6.9 - 7.0 (m, 3H),6.32(t,lH), 4.70(m,lH), 3.90(t,lH), 3.74 (t,lH), 3.5- 3.7 (m, 2H), 3.20 (dd, 2H), 2.9 - 3.1 (m, 4H),2.52(t,2H), 2.34 ( s,3H), 2.71 (s, 3H ), 1.5 -1.9 (m,6H).
(S) - N-[[3 - (3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- methoxyphenyl) -4-oxobutanamide.
XH NMR ( CDCI3, 8) : 8.07(d, 1H), 7.2 - 7.8 (m,6H), 7.71(d,2H ), 6.79 (d,2H ), 6.51(t,lH), 4.81(m,lH), 3.4- 4.0 (m, 4H), 3.71 (s, 3H), 3.15 (qt, 2H), 2.52 (dd, 2H).
(S) -N-[[3-(3 -fluoro -4- benztriazolylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4-(4- chlorophenyl) -4-oxobutanamide.
'H NMR (CDCI3, 8) : 8.09(d, 1H), 7.2 - 7.8 (m,6H), 7.75(d,2H ), 7.35 (d,2H ), 6.29(t,lH), 4.81(m,lH), 3.7 - 4.0(m, 3H), 3.5 - 3.7 (bt, 1H),3.25 (qt, 2H), 2.55 (t, 2H). (S)-N-[[3-(3-fluoro-4-(1,2,4-triazolyl)phenyl)-2-oxo-5- oxazolidinyljmethyl] -4- oxo — 4 - phenylbutanamide.
36

*H NMR (CDCI3, 8) : 8.62 (bs, 1H ), 8.10 ( s, 1H ), 7.7 -7.8 ( m, 2H ),, 7.67 (dd, 2H, ), 7.44 (t,
1H ), 7.2 - 7.4 (m,3H ), 6.49 (t, 1H ), 4.78 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55 (dt, 1H ), 3.30 (ddd,
2H), 2.54 (dd, 2H).
(S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4-(4- methylphenyl) -4- oxobutanamide.
XHNMR (CDC13, 8) : 8.71 (bs, 1H ), 8.10 ( s, 1H), 7.7 -7.9 ( m, 4H ), 7.30 (d, 1H, ), 7.21 (d, 2H
), 6.63 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.64(dt, 1H ), 3.35 (qdd, 2H), 2.5 - 2.6 (m, 2H),
2.35( s,3H).
(S) - N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl] -
4-(4- methoxyphenyl) -4- oxobutanamide.
'H NMR (CDCI3, 8) : 8.68 (bs, 1H ), 8.16 ( s, 1H ), 7.7 -7.9 ( m, 2H ), 7.79( d, 2H ) 7.28 (dd,
1H), 6.85 ( d,2H), 6.58 (t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.82(s,3H), 3.61(dt, 1H ), 3.32
(qdd, 2H), 2.65 (ddd, 2H).
(S) -N-][3-(3 -fluoro -4- (1,2,4 - triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl]
-4-(2,4- dimethylphenyl) -4- oxobutanamide.
!HNMR (CDCI3,8) : 8.69 (bs, 1H ), 8.17 ( s, 1H ), 7.78( t,lH), 7.75 ( d,lH ), 7.60 (d,lH),7.25(d,
1H, ), 7.10 (d, 1H ),6.99(s, 1H ), 6.54( t, 1H ), 4.86 ( m, 1H), 3.8 - 4.1 (m, 3H), 3.65(dt, 1H ),
3.25 (qt, 2H), 2.59 (dt, 2H), 2.38( s,3H), 2.29 (s,3H).
(S) -N-[[3 -(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4- oxo- 4 -(4 - thiomethylphenyl)butanamide.
'H NMR (CDCI3, 8) : 8.57 (bs, 1H ), 8.06 ( s, 1H ), 7.77 (m,2H), 7.61 (d, 2H), 7.19 ( d, 1H ),
7.10 (d, 2H, ), 6.47 (t, 1H ), 4.76 ( m, 1H), 3.8 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25 (qdd, 2H), 2.55
(dq,2H),2.39(s,3H).
(S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide.
lU NMR (CDCI3, 8) : 8.58 (bs, 1H ), 8.06 ( s, 1H ), 7.80(t,lH),7.6 -7.8 ( m, 1H ), 7.67 (d,
2H,),7.32(d,2H), 7.26 (d, 1H ), 6.43 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.55(dt, 1H ), 3.25
(qt, 2H), 2.53(dt, 2H), 1.22( s,9H).
(S) -N-[[3-(3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo -5- oxazolidinyl] methyl]
-4-(2'- methyl - 4 - propylphenyl) -4- oxobutanamide.
'H NMR (CDCI3, 8) : 8.61 (bs, 1H ), 8.09 ( s, 1H ), 7.6 -7.8 ( m, 4H ), 7.24 (dd, 1H, ), 7.07 (d,
2H ), 6.38 (t, 1H ), 4.77 ( m, 1H), 3.7 - 4.0 (m, 3H), 3.54(dt, 1H ), 3.28(qt, 2H), 2.54(dt, 2H),
2.40( d,2H), 1.77 (pent.,lH), 0.81 (d,6H).
(S) - N-[[ 3-(3 -fluoro -4- (1,2,4 — triazolyl) phenyl) -2- oxo -5— oxazolidinyl] methyl]
-4-oxo - 4- (2- thienyl)butanamide.
37

'HNMR (CDCI3, 8) : 8.57 (bs, IH ), 8.05 ( s, IH ), 7.76 (t,lH),7.60(dd,lH), 7.53 (dd,lH), 7.25
(dd, IH, ), 7.01 (d, 2H ), 6.47( t, IH ), 4.78 ( m, IH), 3.7 - 4.0 (m, 3H), 3.56(ddd, IH ), 3.25 (qt,
2H), 2.54 (dt, 2H).
(S) -N-[[3 -(3 -fluoro -4- (1,2,4-triazolyl)phenyl) -2- oxo - 5- oxazolidinyl]methyl]-
4 - (2-naphthyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) : 8.41 (s, IH ), 8.27( s, IH ), 8.02(s,lH), 7.3 -7.9 ( m,6H ), 7.3 - 7.6 (m,
3H), 6.44 (t, IH ), 4.77 ( m, IH), 3.7 - 4.0 (m, 3H), 3.2- 3.7 (m, 3H), 2.5-2.6 (m, 2H).
(S) - N-[[3 - (3 -fluoro -4- (1,2,4 - triazolyl) phenyl) -2- oxo - 5 - oxazolidinyl] methyl]
-4-(4- chlorophenyl) -4- oxobutanamide.
lH NMR (CDCI3, 8) : 8.58 (bs, IH ), 8.07 ( s, IH ), 7.6 -7.9 ( m, 2H ), 7.68 (d, 2H), 7.29 (d,
2H,), 7.2 - 7.3 (m, IH ), 6.31 (t, IH ), 4.81 ( m, IH), 3.7 - 4.1 (m, 3H), 3.55(dt, IH ), 3.25 (qt,
2H), 2.55(dt, 2H).
(S)-N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4-
oxo -4-(2- thienyl)butanamide.
*H NMR (CDCI3, 8) : 7..5 - 7.7 ( m, 2H), 7.3 - 7.5 (m,lH), 6.8 - 7.3(m,3H ), 6.35(t,lH),
4.69(m,lH), 3.89 (t,lH), 3.76(t,lH),3.59(m,2H), 3.21(dd,2H),3.02 (m, 4H), 2.55 (t, 2H), 1.5 -
1.8 (m,6H).
(S) -N-[[3 -(3-fluoro -4-piperidylphenyl) -2-oxo -5- oxazolidinyl]methyl]-4-
(2'- methyl -4- propylphenyl) -4- oxobutanamide.
'H NMR (GDCI3,8) : 8.08 (m, IH ), 7.74 (d, 2H), 7.4 - 7.8 (m, IH ), 7.16 (d, 2H,), 6.97(dd,lH)
6.37 (t, IH ), 4.74 ( m, IH), 3.88 (t, IH), 3.80(t,lH), 3.4 - 3.71 (m, 2H), 3.40(m,4H) 3.25(dd, 2H
), 2.45(d, 2H), 1.80 (pent, IH), 1.5-1.8(m,6H),0.83(d,6H).
(S)-N-[[3-(3-fluoro-4-piperidylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(4
- acetamidophenyl) -4- oxobutanamide.
'H NMR (DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.78 (d, 2H), 7.60 ( d, 2H), 7.36 (dd, IH),
7.06 (dd, IH), 6.93 (t,lH), 4.63 (m, IH), 3.95(t,lH), 3.61 (dd,lH), 3.07(dd,lH), 2.81 (m,4H),
1.99 (s, 3H), 1.55 (m, 4H), 1.44 (m, 2H).
(S) - N-ff 3 -( 3 -fluoro - 4 * piperidylphenyl) - 2 - oxo - J - oxazolidinyl] methyl] -4-
oxo - 4 -phenylbut - 2- enamide.
JHNMR (CDCI3, 8) .-7.7-8.0 (m,3H), 7.2 - 7.6 (m, 5H), 7.01 (d,2H), 6.98 (t, IH), 4.80(m, IH),
4.01(t,lH), 3.85(t,lH), 3.77 (t, 2H), 3.16 (m, 4H), 1.5 - 1.9 (m,6H).
(S) - N-ff 3 - (3 -fluoro - 4 - pyrrolidinylphenyl) -2- oxo -5- oxazolidinyl] methyl] ~4-
oxo- 4-(4- thiomethylphenyl)butanamide.
lU NMR (CDCI3, 8) :7.70 (d,2H), 7.60 (bd,lH), 7.0 - 7.3 (m, 3H), 6.91 (d,lH), 6.47 (t, IH),
4.71(m, IH), 3.87(t,lH), 3.4 - 3.8 (m,3H ), 3.45(m, 4H) 3.21 (dd, 2H), 2.54 (t, 2H), 2.45 (s,3H),
2.06(m,4H).
38

(S)-N-[[3-(3-fluoro-4-pyrrolidinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(2-naphthyl) -4- oxobutanamide.
!H NMR (CDC13, 8) : 8.35 (s, IH ), 7.5 - 8.1 (m, 8H ), 6.91(d,lH) 6.53 (t, IH ), 4.72 ( m, IH),
3.38 (m, 4H), 3.2 - 4.0 (m, 6H), 2.61(m, 2H), 1.99 (m,4H).
(S) -N-[[3-(3 -fluoro -4- pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] — 4 —
(2'- methyl - 4 -propylphenyl) - 4 -oxobutanamide.
lU NMR (CDCI3, 8) :7.75 (d,2H), 7.46 (m,lH), 7.1 - 7.3 (m, 3H), 6.95 (d,lH), 6.44 (t, IH),
4.70(m, IH), 3.3 - 4.0 (m,4H ), 3.41(m, 4H) 3.24 (dd, 2H), 2.55 (t, 2H), 2.45 (d,2H),
2.01(m,4H), 1.81 (pent,lH), 0.83 (d, 6H).
(S) -N-][3-(3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-
(2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide.
lH NMR (CDCI3, 8) :7.76 (d,2H), 7.2 7.5(m, 4H), 6.95 (d,lH), 6.33 (t, IH), 4.69(m, IH),
3.88(t,lH), 3.71(t,lH), 3.6 - 3.7 (m,2H ), 3.45(m, 4H) 3.23 (dd, 2H), 2.56 (t, 2H), 1.94 (m,4H),
1.26(s,9H).
(S^J - N-[[3 - (3 -fluoro - 4 -pyrrolidinylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4 —
(4 - acetamidophenyl) -4- oxobutanamide.
'H NMR (CDCU, 8) : 7.2 - 7.8 (m, 7H), 6.85 (d,lH), 6.47 (t, IH), 4.67(m, IH), 3.81(t,lH), 3.3 -
3.7 (m,3H ), 3.46(m, 4H) 3.16 (m, 2H), 2.3 - 2.9 (m,6H), 2.06(s,3H).
(Sp -N-[]3-(3-fluoro -4- pyrrolidinylphenyl) -2-oxo - 5- oxazolidinyl]methyl]-4-
oxo - 4 -phenylbut - 2- enamide.
'HNMR (CDCI3, 8) :7.8 - 7.9 (m,3H), 7.0 - 7.6 (m, 5H), 6.93 (d,lH), 6.75 (m,lH), 4.76(m, IH),
4.02(t,lH), 3.74 (m, 3H), 3.30 (m, 4H), 1.95 (m,4H).
(S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-
4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
!HNMR (CDCI3, 8) :7.78 (d,2H), 7.33 (dd,lH),6.99 (d,lH), 6.83 (t,lH), 6.81 (d, 1H),6.38 (t, IH)
4.69(m, IH), 3.86 (t,lH), 3.79 (s,3H), 3.5 - 3.8 (m,3H ), 3.41(m, 4H) 3.20 (m, 6H), 2.73(m,4H)
2.53 (t, 2H).
(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-
4 - (2,4 - dimethylphenyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) :7.55 (d,lH), 7.33 (dd,lH), 6.96 (m,3H), 6.81(t,lH), 6.22 (t, IH), 4.69(m,
IH), 3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.17(m, 6H) 2.73 (t, 2H), 2.45 (d,2H),2.51 (t,2H), 2.34(s,3H),
2.27 (s,3H).
(Si)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-
4 - oxo -4-(2- thienyl)butanamide.
!H NMR (CDCI3, 8) :7.63 (d,lH), 7.55 (d,lH), 7.33 (dd, IH), 7.05 (dd,2H), 6.85(t, IH), 6.31
(t,lH), 4.69(m, lH),3.88(t,lH), 3.5 - 3.8 (m,3H ), 3.23(m, 6H) 2.73 (m, 4H), 2.55 (t, 2H).
39

(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - J - oxazolidinyl] methyl] -4-(4- acetamidophenyl) -4- oxobutanamide.
'HNMR ( DMSOdfi, 8) : 10.18 (s, IH), 8.23(t, IH), 7.73(d, 2H), 7.59 (d, 2H), 7.38 ( dd, IH), 7.08(dd,lH), 6.99 (t, IH), 4.65 (m, IH), 3.95(t,lH),3.62(dd,lH), 3.08(m, 6H), 2.66 (m, 4H), 1.97 (s,3H).
(S) - N -[[ 3 - (3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl] - 4 -oxo - 4 - (4 - thiomethylphenyl)butanamide.
•HNMR (CDC13,8) : 7.70 (d, 2H), 7.32 (dd,lH),7.14 (d, 2H,), 6.99(dd,lH), 6.82(t,lH), 6.33 (t, IH ), 4.68 ( m, IH), 3.86 (t, IH), 3.4 - 3.8 (m, 3H), 3.20(dt, 2H ), 2.90(t,4H) 2.53(t, 2H), 2.44(s,3H), 1.67 (m,4H), 1.5 (m,2H).
(S) -N-[[3-(3-fluoro-4-piperidylphenyl) -2-oxo-5- oxazolidinyl]methyl] -4-(naphthyl) -4- oxobutanamide.
'H - NMR ( CDCI3) : 8.36 (s, IH ), 7.7 - 7.9 (m, 4H, ), 7.4 - 7.6 (m, 2H ), 7.32 (dd,lH), 6.99(d,lH), 6.78(t,lH), 6.43 (t, IH), 4.70 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.39(dt,2H), 2.86(t,4H), 2.61(t, 2H), 2.10(m,4H),1.50 (m,2H).
S) -N-[[ 3- (3 -fluoro -4- piperidylphenyl) -2- oxo - 5 - oxazolidinyl] methyl] -4-(2',2' - dimethyl -4- ethylphenyl) -4- oxobutanamide.
lUNMR (CDCI3,8) : 7.75 (d, 2H), 7.37 (d,2H),7.31 (dd, IH, ), 7.00(dd,lH), 6.84(t,lH), 6.37 (t, IH ), 4.68 ( m, IH), 3.87 (t, IH), 3.5 - 3.8 (m, 3H), 3.25(dt, 2H ), 2.91(t,4H) 2.54(t, 2H), 2.23(m,4H), 1.5 (m,2H), 1.26(s,9H).
(S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4-oxo -4-(4- thiomethylphenyl)butanamide.
'HNMR (CDCI3, 8) : 8.08 (d, 2H ), 7.77 (dd, IH, ), 7.63(d,2H), 7.2 - 7.5 (m, 4H ), 7.12 (d,2H), 6.41 (t, IH ), 4.81 ( m, IH), 3.98 (t, IH), 3.7 - 3.9 (m, 2H), 3.54(dt,lH), 3.22(qdd,2H), 2.54(dd, 2H), 2.36(s,3H).
(S) -N-[] 3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5 - oxazolidiny] methyl] -4-(2-naphthyl) -4- oxobutanamide.
'HNMR (CDCI3, 8) : 8.35( s,lH), 8.08 (d, IH ), 7.6 - 7.8(tn,5H), 7.2 - 7.6 (m, 7H ), 6.41 (t, IH ), 4.82 ( m, IH), 3.8 - 4.0 (m, 3H), 3.3 - 3.7(m,3H), 2.64(dd, 2H).
(S) -N-[[3-(3 -fluoro -4- benztriazofylphenyl) -2- oxo - 5- oxazolidinyl]methyl]-4 - (2',2' - dimethyl- 4 - ethylphenyl) -4- oxobutanamide.
*H NMR (CDCI3, 8) : 8.08 (d, IH ), 7.80 (dd, IH, ), 7.70(d,2H), 7.57(t, IH), 7.2 - 7.5 (m, 4H ), 7.08 (d,2H), 6.41 ( t, IH ), 4.80 ( m, IH), 3.7 - 4.0 (m, 3H), 3.55(dt,lH), 3.1 - 3.4(m,2H), 2.54(dd, 2H), 2.37(d,2H), 1.72(pent,lH), 0.76(d,6H).
40

(S)-N-[[3-(3-Jluoro-4- henzotriazolylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide.
JHNMR(CDC13, 5) :7.2 - 8.0 (m,13H), 6.95 (d,lH), 6.65 (m,lH), 4.89(m, IH), 4.18(t,lH), 3.7-4.0 (m, 3H).
(S) -N-[[3-(3-Jluoro-4-benztriazolylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 -(4- acetamidophenyl) -4- oxobutanamide.
!HNMR (DMSOde, 8) : 10.16 (s, IH), 8.29(t, IH), 8.12 (d, IH), 7.79 (m, 4H), 7.58 ( d, 2H), 7.4 - 7.5 (m, 4H), 4.74 (m, IH), 4.13(t,lH),3.08(dd,lH), 3.10 (t, 2H), 1.97 (s, 3H). (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl] -4-(2',2'- dimethyl -4- ethylphenyl) -4- oxobutanamide.
lH NMR (CDCI3,8) : 7.76 (d, 2H), 7.53 (dd, 1H),7.39 (d, 2H +1H, ), 7.02(d,lH), 6.29 (t, IH ), 4.71 ( m, IH), 3.89 (t, IH), 3.79(t,lH), 3.5 - 3.7 (m, 2H), 3.38(m, 4H ), 3.24 (dd,2H), 2.92(m,4H) 2.54(t, 2H), 1.26(s,9H).
(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo - 5 - oxazolidinyl]methyl]-4 - oxo - 4 -phenylbut - 2- enamide.
JH NMR (CDCU, 8) :7.8 - 7.9 (m,3H), 7.3 - 7.7 (m, 5H), 6.8 -7.0 (m,3H), 4.81(m, IH), 4.05(m,lH), 3.75 (m, 3H), 3.49 (m, 4H), 3.10 (m,4H).
(S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4-(fi- naphthyl) -4- oxobutanamide.
!H NMR (CDCI3, 8) : 8.35 (s, IH), 7.7-8.0 (m, 4H), 7.3-7.7 (m, 5H), 7.01 (m, IH), 6.48 (m, IH), 4.74 (m, IH), 3.80 (m, 3H), 3.60 (m, IH), 3.37 (m, 6H), 2.93 (m, 4H), 2.60 (m, 2H) (S)-N-[[3-(3-fluoro-4-thiomorpholinylphenyl)-2-oxo-5- oxazolidinyl]methyl]-4- (4- chlorophenyl) -4-oxobutanamide.
!H NMR (CDCI3, 8) : 7.74 (d, 2H), 7.54 (d, IH), 7.34 (d, 2H+1H), 6.98 (d, IH), 6.35 (t, IH), 4.78 (m, IH), 3.88 (t, IH), 3.5-3.8 (m, 3H), 3.38 (m, 4H), 3.22 (dd, 2H), 2.93 (m, 4H), 2.54 (t, 2H).
(S) -N-[[3-(3 -fluoro -4- thiomorpholinylphenyl) -2- oxo -5- oxazolidinyl] methyl] -4 - (2,4 - dimethyl- 4 ethylphenyl) -4- oxobutanamide.
lH NMR (CDCI3, 8) : 7.95 (m, IH), 7.74 (d, 2H+1H), 7.77 (d, 2H), 7.07 (d, IH), 6.38 (t, IH), 4.76 (m, IH), 3.91 (t,lH), 3.4-3.8 (m, 3H), 3.58 (m,4H), 3.25 (dd, 2H), 3.1 (m, 4H), 2.54 (t, 2H), 2.46 (d, 2H), 1.80 (pent, IH), 0.85 (s, 3H), 0.82 (s, 3H). Microbiology: Pharmacological testing
The compound of formula (I) of the present invention displayed antimycobacterial activity when tested by in vitro growth inhibition assay and agar incorporation methods. The minimum inhibitory concentrations (jag/ml) obtained for representative compounds of formula (I)
41

against M. tuberculosis including sensitive and resistant strains are summarized in Table-I. The MIC value of a representative preferred Compound No. 30 of formula I against different species of mycobacteria is summarized in Table-II. in vitro Growth Inhibition assay
The ability of the compounds 1-78 of formula (I) of this invention to inhibit the growth of Mycobacterium species was determined by the BACTEC 460 TB system. The reference strain M tuberculosis H37Rv ATCC 27294 was grown in Middlebrook 7H9 broth containing 10% ADC
supplement at 37°C on a rotay shaker at 150 rpm for grown for 7days. The turbidity of the culture was adjusted to 1.0 Mc farland. The BACTEC 7H12B medium vials were seeded with 0.1ml of the 1.0 Mc farland adjusted M. tuberculosis culture. In the control vials 0.1ml of the culture was added after lOOfold dilution of the initial inoculum. Stock solution of lmg/ml of each compound was prepared in DMSO in separate sterile tubes. The compounds were further diluted to concentration of 25 ^g/100 ul, 0.1ml was than added to the 7H12B vial containing mycobacterial culture so that final concentration of the compound 6.25 u.g/ml. The cap in all the vials were cleaned with isopropanyl alcohol and kept in racks. The vials were then incubated at 37°C without shaking. Test vials was read daily on the BACTEC system till the GI of the control vial reached > 30.Once the GI in the control reached 30 AGI (GI = GI (n> - GI („.i) ) was determined for all test and control vials. If AGI of test vial is less than that of the control vial the culture was sensitive to the test compound. in vitro Agar Dilution assay
MIC of compound of formula (I) of this invention against strains of Mycobacterium were determined by a reference agar dilution method as per the NCCLS- M24-T2. recommendations. The compounds were dissolved in DMSO and diluted twofold to obtain ten serial dilutions of each compound. Appropriate volume of compounds were incorporated into duplicate plates of Middlebrook7H10 agar medium supplemented with 10% Middlebrook supplement oleic acid-albumin-dextrose (OADC) enrichment at concentration of 0.03u,g/ml to 16|j,g/ml. Test organisms (mycobacterium strains) were grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement. After 7 days of incubation at 37°C the broths were adjusted to the turbidity of 1.0 McFarland standard; the organism were further diluted 10 fold in sterile water containing 0.10% Tween-80. The resulting mycobacterial suspensions were spotted (3-5jxl/spot) onto drug supplemented 7H10 media plates. The plates were sealed and incubated at 37°Cfor 3-4 weeks in upright position. The MIC was recorded as the lowest dilution of the drug that completely inhibited the growth of test organisms. Test isolates included 10 clinical isolates that were generally susceptible to common tubercular agents and 10 strains that were resistant to one or more standard anti tubercular drugs. Appropriate reference strains and control drug was included in each batch of test.
42

in vivo studies:
The efficacy of the compound of formula (I) of this invention was also evaluated in murine model of pulmonary tuberculosis. Mycobacterium tuberculosis cultures grown in Middle brook 7H9 broth containing 0.05% Tween-80 and 10% ADC supplement at 37°C for 7 days on a rotary shaker. For, animal inoculation liquid cultures were declumped by brief sonication and were diluted appropriately in 7H9 broth to obtain a concentration of lxl07CFU's/ 0.2ml. Four-week-old male outbred Swiss albino mice housed in a pathogen free, biosafety level 3 environment within micro isolator cages were used throughout the study. Infections were produced by intravenous inoculation into caudal tail vein of 0.2ml of declumped M. tuberculosis suspension. Following infection, mice were randomly distributed in different groups of six each.
Treatment for initial study was started one day after infection. For, treatment Compound No. 30 of formula I was dissolved in 10% PEG. Isoniazid was dissolved in sterile water. The drugs were prepared each morning prior to administration. Therapy was given 5 days per week for four weeks. All the agents were administered by gavage and were dosed at 50,25,12.5mg / kg of body weight. Control group of infected but untreated mice were killed at the initiation of therapy (early control) or at the end of the treatment period (late control). Mice were sacrificed by cervical dislocation 3-5 days after the administration of the last dose of drug. The spleens and right lung were removed aseptically and homogenized in tissue homogeniser. At least 4 serial tenfold dilution of the homogenate was plated onto selective Middlebrook 7H11 agar plates in duplicate. The colony counts were recorded after incubation at 37°C for 4 weeks. The viable cell counts were converted to Logio values. A compound showing 2 Log reduction in viable counts compared to the controls was considered significant.
The in vivo data for a representative compound of formula (I) is given in Table-II.
Acute toxicity of Compound No. 30 of Chart-I was estimated in mice and the LDo was found to be >1000 mg/kg P. O.
43

Table-I: in vitro activity of compounds 1 to 58 of formula (I),

Compound No. Growth inhibition of
M.tuberculosis
27294 MIC (fig/ml) against

M.tuberculosis 27294 Clinical isolates

Sensitive Resistant
1 + 16 4-16 >16
2 + 8 8 8
8 + 2 .5-2 2-4
13 + 2 2 2-4
14 + 0.25 0.25-0.5 4->16
15 + >16 >16 >16
16 + 0.5 0.5 0.5(>16)
17 + 0.5 1.0 0.5-1.0
18 + 4- 1-4 8->16
19 + 2 1-2 2
20 + 1 1-2 2-4
21 + 0.5 0.5-2 0.5(>16)
25 + 4 4-16 4->16
27 + >16 >16 >16
28 + 0.5 1-2 2-8
30 + 0.5 0.5 0.5-2
31 + 1 1-2 1-4
32 + 0.25 0.25-0.5 4-(>16)
33 + 0.5 1 0.5-2
34 + >16 >16 >16
35 + 4 2-4 4-8
36 + 4 4-8 4-8
44

Table-I Contd....

39 + 2 2-4 2-8
40 + 1 1-2 1-2
43 + 1 0.5-1.0 1-2
44 + 1 0.5-2 1-4
45 . + 2.0 2-4 2-4
46 + 2 2-4 2-8
47 + 1 1-2 2-4
48 + 2 2-4 2-8
49 + 4 4-16 4-16
50 + 2 2-4 2-4
51 + 8 8->16 8->16
52 + 2 2 4->16
53 + >16 >16 >16
54 + 8 8-16 >16
55 + >16 >16 >16
56 + >16 >16 >16
57 + 16 16->16 >16
58 + 8 8-> 16 8-> 16
Isoniazid + 0.25 0.12- .25 8 - >16
Linezolid + 0.5 0.25-0.5 1.0-2.0
Table-II MIC values of compound of formula (I) against different species ofMycobacteria

Sr.
No. Compound No. MIC (ug/ml)

M. tuberculosis M.avium-
intracellular
complex M.fortuitum M.kansai

Sensitive Resistant

1 Compound 30 of formula I 0.50 0.50-2.0 8.0->16.0 >16.0 8.0
2 Isoniazid 0.25 4.0-> 16.0 8.0->16.0 >16.0 >16.0
45

Table-m in vivo activity of Compound of formula (I) against M. tuberculosis ATCC 27294" infection
in Swiss albino mice

Sr. No. Drug& Dose b (mg/kgday" ') or group Mean Logio No. of CFU Mean Logio No. of reductionc

Lung Spleen Lung Spleen
1 Compound 30 of Chart-I
50mg/kg 25mg/kg 12.5mg/kg 2.12 2.21 4.34 2.09 2.13 4.30 2.40 2.30 0.20 2.53 2.49 0.26
2 Isoniazid
50mg/kg 25mg/kg 12.5mg/kg 2.03 2.11 2.95 1.92 2.11 2.94 2.49 2.41 1.57 2.70 2.51 1.68
3 Infected early control 4.52 4.62
4 Infected late control 6.57 6.37
a- inoculation of logio:- 7.00 Mycobacteria.
b- mice were dosed 5 day/week for 4 weeks. From day 1 -28.
c- difference in mean logio number CFU from that of early controls.
The compound of formula I of this invention may be administrated to a subject such as a human being or an animal in need of such an administration through any route appropriate to the condition to be treatede. Suitable routes of administration include oral, rectal, nasal, topical (both buccal and sublingual), vaginal and parenteral (including subcutaneous, intramuscular, intradermal, intrathecal and epidural).
Pharmaceutical compositions of compound of formula I can be prepared in adjunction with inert pharmaceutically acceptable carriers, which can either be solid or liquid.
Solid form preparations include powders, tablets, dispersible granules, capsules, cachets, suppositories and ointments. The solid carriers can be one or more substances which may act also as diluents, flavouring agents, solubilisers, lubricants, suspending agents, binders or tablet disintegrating agents. It can also be finely divided solid which is in admixture with finely divided active compound. Suitable solid carriers are lactose, pectin, dicalcium phosphate, microcrystalline cellulose, sucrose, kaolin, dextrin, gelatin, starch, tragacanth, low melting wax, coca butter and the like.
Liquid preparations include solutions, suspensions and emulsions, e.g. solutions of compound of formula I in water or water-propylene glycol mixture for parenteral injection. Liquid preparations can also be formulated along with non-ionic surfactants and edible oils such as corn, peanut and sesame oils. Aqueous solutions for oral use can be prepared by dissolving the active component in water and adding suitable colorants, flavours stabilizing and thickening
46

agents, as required. Aqueous suspension for oral use can be made by dispersing the finely divided active component in water with a viscous material, e.g. natural or synthetic gums, resins, methyl cellulose, sodium carboxymethyl cellulose and othe known suspending agents. The adjuvants may also include preserving agents and anti-oxidants.
Compositions for topical application may take the form of liquids or gels, containing a therapeutically effective concentration of compound of formula I admixed with a dermatologically acceptable carrier.
The pharmaceutical preparations may be in unit dosage form. In such form, the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage can be in the form of tablets, capsules, powdersin vials or ampoules, ointments, gels, creams or any other form. The quantity or concentration of the active compound in such unit dose preparations may be varied or adjusted according to the particular application and potency of the active ingredient.
47

A compound of formula (I) and its pharmaceutical^ acceptable salts

wherein,
A is either hydrogen or fluorine,
B is either hydrogen or fluorine,
A and B together is hydrogen and fluorine,
Ri is a group of formula,

wherein,
Q is either an alkyl group of two carbon atoms, an alkene group of two carbon atoms or
an alkyne group of two carbon atoms
Y is oxygen, sulfur or an amino function of formula NR3
wherein,
R3 is an alkyl group of 1-4 carbon atoms, both saturated and unsaturated, which can be
straight or branched; cycloalkyl of 3-7 carbon atoms; CHO, -COOH, -COOR,; COCR,;
CN; aryl or heteroaryl
wherein,
Rt is an alkyl group of 1-4 carbon atoms, an alkene of 3-6 carbon atoms, an alkyne of
3-6 carbon atoms.
Ar is a substituted phenyl ring or a substituted pyridine ring of formula

—O-R3
or Ar is a five membered ring of formula
48

or Ar is a fused bicyclic phenyl or pyridine ring of formula

wherein,
M is either CH or N
Z is CH, NH, O, or S,
X is a group selected from OR,, NR4R5, N02, SR,, SOOR,, SOONR4R5, F, CI, Br or I,
wherein R4 is as defined hereinbefore, and
and R3 is as defined hereinbefore
R5 is hydrogen or R4
R2 is selected from the groups shown below, and the corresponding N-oxides thereof.

A compound according to Claim 1 wherein in said compound of formula I Aryl is phenyl substituted with (0) or (1) of F, CI, "OCH3, "OH, "NH2, CrC4 alkyl, 0-C(0)-OCH3," N02or"CN.
49

3. A compound according to Claim 1 wherein said compound of formula I is selected from the group consisting of:
1) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl
] methyl ] - 4 - oxo - 4 - phenylbutanamide.
2) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
3) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
4) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - oxobutanamide.
5) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
6) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
7) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methlyphenyl) - 4- oxobutanamide.
8) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
9) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzylpiperazinyl) phenyl ] - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methylphenyl) - 4 - oxobutanamide.
10) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
11) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide.
12) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4- oxobutanamide.
13)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
14) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - chlorophenyl) - 4 - oxobutanamide.
15) (S) - N -[ [ 3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 4 - methyl phenyl) - 4 - thiooxobutanamide.
16) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl 1 methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide.
17) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
50

18) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
19) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl]-4-oxo-4-(2-thienyl)butanamide.
20) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2',2'- dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
21)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -(4- thiomethyl) phenylbutanamide.
22) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
23) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
24) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - [methylbenzylamino ] phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
25) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
26) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) — 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
27) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
28) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide.
29) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl)butanamide.
30) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ]-4-(4-2- naphthyl) - 4 - oxobutanamide - N - oxide.
31)(S)-N-[[3-(3- fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (2 - thienyl)butanamide - N - oxide.
32) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide - N - oxide.
33) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - [4 - ( 2'- methyl - 4 -propylphenyl) - 4 - oxobutanamide - N -oxide.
34) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - morpholinylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
51

35) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4- oxobutanamide.
36) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4- oxobutanamide.
37) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2,4 - dimethylphenyl) - 4- oxobutanamide.
38) (S) - N -[ [ 3 - (3 - fluoro - 4 - benztriazolylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
39) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
40) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbutanamide.
41) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methylphenyl) - 4 - oxobutanamide.
42) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 4 - methoxyphenyl) - 4 - oxobutanamide.
43) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
44) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo- 4 -( 4 - thiomethylphenyl )butanamide.
45) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
46) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
47) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4- (2- thienyl)butanamide.
48) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2- naphthyl) - 4 - oxobutanamide.
49) (S) - N .-[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
50) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
51) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2,4 - difluorophenyl) - 4 - oxobutanamide.
52) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 -( 2 - thienyl)butanamide.
52

53) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 - oxobutanamide.
54) (S) -N-[[3-(3- fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
55) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
56) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo- 4 -■ ( 4 - thiomethylphenyl )butanamide.
57) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2 - naplrthyl) - 4 - oxobutanamide.
58) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2'- methyl - 4 - propylphenyl) - 4 -oxobutanamide.
59) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
60) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
61)(S)-N-[[3-(3- fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
62) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - methoxyphenyl) - 4 - oxobutanamide.
63) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2,4 - dimethylphenyl) - 4 - oxobutanamide.
64) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 2 - thienyl )butanamide.
65) (S) - N -[ [ 3 - ( 5 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
66) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - oxo - 4 - (4 - thiomethylphenyl)butanamide.
67) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl ) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
68) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 - oxo - 5 - oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 - oxobutanamide.
69) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - ( 4 - thiomethylphenyl )butanamide.
70) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - ( 2 - naphthyl) - 4 - oxobutanamide.
53

71) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
72) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
73) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - benzotriazolylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - acetamidophenyl) - 4 - oxobutanamide.
74) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2',2' - dimethyl - 4 - ethylphenyl) - 4 -oxobutanamide.
75) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - oxo - 4 - phenylbut - 2- enamide.
76) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) --2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (2 - naphthyl) - 4 - oxobutanamide.
77) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - '2 - oxo - 5 -oxazolidinyl ] methyl ] - 4 - (4 - chlorophenyl) - 4 - oxobutanamide.
78) (S) - N -[ [ 3 - ( 3 - fluoro - 4 - thiomorpholinylphenyl ) - 2 - oxo - 5 -
oxazolidinyl ] methyl ] - 4 - (2,4 - dimethyl- 4 ethylphenyl) - 4 - oxobutanamide.
- '
4. A compound as claimed in claim 3 wherein said compound of formula I is selected from the group of N-oxide of the said compounds 1 to 78.
5. A pharmaceutical composition comprising a) atleast one of I) any compound of claims 1 to 4 and II) its pharmaceutically acceptable salts and b) a pharmaceutically acceptable carrier.
6. A pharmaceutical composition according to claim 5 comprising a solid or liquid preparation.
7. A pharmaceutical composition as claimed in anyone of claims 5 to 6 for oral or parenteral administration.
8. A method of preparation of the compound of formula I and/or its pharmaceutically acceptable salts comprising:
coupling of the amino fragment of compound of formula II
5^

(II)

with a carboxylic acid of formula III in the presence of an acid activating group or a dehydrating agent in a suitable solvent.

(Ill)

wherein R2 has the same meaning as given in claim 1.
9. A method as claimed in claim 8 wherein the compound of formula II is preferably selected
from (S) - N -[3 - (3 - fluoro - 4 - morpholinylphenyl) - 2 - oxo - 5 - oxazolidinyl]
methyl amine, (S) - N -[3 - (3 - fluoro - 4 - thiomorpholinylphenyl) - 2 - oxo - 5 -
oxazolidinyl] methyl amine, (S) - N -[3 - ( 3 - fluoro - 4 - piperidylphenyl) - 2 -
oxo - 5 - oxazolidinyl] methyl amine,(S) - N -[3 - ( 3 - fluoro - 4 -
benzylpiperazinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3
- (3 - fluoro - 4 - pyrrolidinylphenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, (S) - N -[3 - (3 - fluoro - 4 - (1,2,4 - triazolyl) phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine, S) - N -[3 - (3 - fluoro - A - benzotriazolylphenyl) - 2 - oxo - 5 -oxazolidinyl] methyl amine, and (S) - N -[3 - (3 - fluoro - 4 - [methylbenzylamino] phenyl) - 2 - oxo - 5 - oxazolidinyl] methyl amine.
10. A method as claimed in anyone of claims 8 or 9 wherein the compound of formula III is
selected from 4-(2-Naphthyl)-4-oxobutanoic acid, 4-Oxo-4-(2-Thienyl)butanoic acid, 4-Oxo-4-(4-thiomethyl)phenylbutanoic acid, 4-oxo-4-(2' methy lpropyl)phenylbutanoic acid, 4-Oxo-4-(2',2'dimethylethyl)phenylbutanoic acid, 4 -(4 -methylphenyl)- 4 -
5S

oxobutanoic acid,4 - (2,4 -dimethylphenyl) - 4 - oxobutanoic acid,4 - (4 -
methoxyphenyl)- 4 - oxobutanoic acid,4 - ( 4- chlorophenyl) - 4 - oxobutanoic acid,
. 4 - (2,4 -dichlorophenyl) - 4 - oxobutanoic acid, 4 - (2,4 -difluorophenyl) - 4 -
oxobutanoic acid,4 -(2- Naphthyl)- 4 - oxobutanoic acid,4 - (4 -acetamidophenyl) -4 -
oxobutanoic acid, (2 E/Z) - Oxo - 4- phenylbut - 2- enoic acid, and 4 - oxo - 4 -
phenyl - but - 2 - ynoic acid.
11. A compound of formula I, its pharmaceutically acceptable salts and pharmaceutical compositions obtained thereof substantially as herein described and illustrated.
Dated this 5th day of March 2005
Dr. Sanchita Ganguli
Of S. MAJUMDAR & CO.
Applicants' Agent
5t

Documents:

173-mumnp-2005-claims(granted)-(27-8-2007).doc

173-mumnp-2005-claims(granted)-(27-8-2007).pdf

173-mumnp-2005-correspondence(27-8-2007).pdf

173-mumnp-2005-correspondence(ipo)-(24-7-2007).pdf

173-mumnp-2005-form 1(7-3-2005).pdf

173-mumnp-2005-form 18(9-3-2005).pdf

173-mumnp-2005-form 2(granted)-(27-8-2007).doc

173-mumnp-2005-form 2(granted)-(27-8-2007).pdf

173-mumnp-2005-form 3(7-3-2005).pdf

173-mumnp-2005-form 5(7-3-2005).pdf

173-mumnp-2005-form-pct-ipea-409(7-3-2005).pdf

173-mumnp-2005-form-pct-isa-210(7-3-2005).pdf

173-mumnp-2005-power of attorney(7-3-2005).pdf

« Previous Patent

Next Patent »

Patent Number

210892

Indian Patent Application Number

173/MUMNP/2005

PG Journal Number

42/2008

Publication Date

17-Oct-2008

Grant Date

15-Oct-2007

Date of Filing

07-Mar-2005

Name of Patentee

LUPIN LIMITED

Applicant Address

159, C.S.T. ROAD, KALINA, SANTACRUZ (EAST), MUMBAI,

Inventors:

#	Inventor's Name	Inventor's Address
1	ARORA SUDERSHAN KUMAR	LUPIN LIMITED (RESEARCH PARK), 46A/47A, NANDE VILLAGE, TALUKA MULSHI, PUNE 411 042,

PCT International Classification Number

C07D 263/20

PCT International Application Number

PCT/IN2002/00190

PCT International Filing date

2002-09-20

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA