Indian Patents. 231500:A PROCESS FOR THE PREPARATION OF COMPOUND 1,1'- { [ (BISALKANE-1,N-DIYL) PIPERAZINE] DIOXY } BIS (11AS)-7- METHOXY-1,2,3,11 A-TETRAHYDRO-5H-PYRROLO[2,1-C] [1,4] BENZODIAZEPIN-5-ONE

Title of Invention	A PROCESS FOR THE PREPARATION OF COMPOUND 1,1'- { [ (BISALKANE-1,N-DIYL) PIPERAZINE] DIOXY } BIS (11AS)-7- METHOXY-1,2,3,11 A-TETRAHYDRO-5H-PYRROLO[2,1-C] [1,4] BENZODIAZEPIN-5-ONE
Abstract	The present invention provides a process for the preparation of 1, 1'-{[(bisalkane-l,N-diyl)piperazine]dioxy}bis(11aS)-7-methoxy-1,2,3,11a-tetrahydio-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one useful as potential antitumour agents with aliphatic chain length variations for the compounds and it also describes the anticancer (antitumour) activity

Full Text	A process for the preparation of compoundl,l'-{[(bisalkane-l,N-diyl)piperazine] dioxy}bis(11 aS)-7-methoxy-l ,2,3,11 a-tetrahydro-5H-pyrrolo [2,1 -c\ [l,4\|benzodiazepin-5-one Field of the invention The present invention relates to novel pyrrolo[2,l-c][l,4]benzodiazepines useful as potential antitumour agents. This invention relates to a process for the preparation of new pyrrolo[2,l-c][l,4]benzodiazepines useful as antitumour agents. More particularly, it provides a process for the preparation of l,l'-\|[(bisalkane-l,N-diyl)piperazine]dioxy\| bis[(11aS)-7-methoxy-l, 2, 3, 11a-tetrahydro-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one, with aliphatic chain length variations for the compounds and it also describes the anticancer (antitumour) activity. The structural formula of novel pyrrolo[2,l-c][l,4]benzodiazepine is as follows, wherein n = 2 to 10. (Formula Removed) Background and Prior art references Pyrrolo[2,l-c][l,4]benzodiazepines antitumour antibiotics are commonly known as anthramycin class of compounds. In the last few years, a growing interest has been shown in the development of new pyrrolo[2,l-c][l,4]benzodiazepines (PBDs). These antibiotics react covalently with DNA to form an N2-guanine adduct that lies within the minor groove of duplex DNA via an acid-labile aminal bond to the electrophilie imine at the N10-CT1 position. (Kunimoto, S. Masuda, T. Kanbayashi, N. Hamada. M. Naganawa, H. Miyamoto, M. Takeuchi, T. and Unezawa, H. J. Antihiot., 1980, ;o. 665.; Kohn. K.W. and Speous, C.L. J. Mol. Biol, 1970, 51, 551.; Hurley, 1.11 (iairpla, C. and Zmijewski, M. Biochem. Biophys. Acta., 1977, 475, 521.; Kaplan, D..I. and Hurley, L.H. Biochmestry, 1981, 20, 7572). The molecules have a right-handed twist, which allows them to follow the curvature of the minor groove of B-form double-stranded DNA spanning three base pairs. Recently PBD dimers have been developed that comprises two C2-exo-methylene- substituted DC-81 subunits tethered through their C-8 position via an inert propanedioxy linker. (S. J. Ciregson. P. W.Howard, J. A. Hartely, N. A. Brooks, L. J Adams, T. C. Jenkins, L. R. Kelland, and D. E.Thurston. J.Med.Chem., 2001, 44, 737). A recent development has been the linking of two PBD units through their C-8 positions to give bisfunctional alkylating agents capable of cross-linking DNA (Thurston, D. E. Bose, D. S. Thomson, A. S. Howard, P. W. Leoni, A. Croker, S. J. Jenkins, T. C. Neidle, S. and Hurley, L. H. J. Org. Chem., 1996, 61, 8141-8147). Recently, a noncross-linking mixed imine-amide PBD dimers have been synthesized that have significant DNA binding ability and potent anti tumour activitiy (Kamal, A.; Laxman, N.; Ramesh, G. Ramulu, P and Srinivas, O. US Pat. No. 636233. dt 26-03-2002.; Kamal, A. Ramesh, G.; Laxman, N.; Ramulu, P.; Srinivas, O.; Neelima, K.; Kondapi, A. K. Srinu, V. B.; Nagarajaram, H. M. J. Med. Chem. 2002, 45, 4679 ). Naturally occurring pyrrolo[2,l-c][l,4]benzodiazepines belong to a group of antitumour antibiotics derived from Streptomyces species. Recently, there is much (Formula Removed) impetus for the PBD systems as they can recognize and bind to specific sequence of DNA. Examples of naturally occurring PBD's include anthramycin, DC-81, tomaymycin, sibiromycin and neothramycin. However, the clinical efficacy for these antibiotics is hindered by several limitations, such as poor water solubility and cardiotoxicity and development of drug resistance and metabolic inactivation. Objects of the invention The main object of the present invention is to provide new pyrrolo[2,l-c][l,4]benzodiazepines useful as antitumour agents. Another object of the invention is to provide pharmaceutical compositions comprising novel pyrrolo[2,1 -c][ 1,4]benzodiazepines useful as anti-cancer agents Another objective of the present invention is to provide a process for the preparation of novel pyrrolo[2,l-c][l,4] benzodiazepines.. Summary of the invention Accordingly, the present invention provides novel pyrrolo[2,l-c][l,4]benzodiazepine of formula VI where n is 2 to 10; and a process for the preparation of the same. (Formula Removed) Detailed Description of the Invention In accordance, the present invention provides analogues of 1, l'-{[(bisalkane-1 ,N-diyl)piperazine]dioxy} bis( 11 aS)-7-methoxy-1,2,3,11 a-tetrahydro-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one] of formula (VI) (Formula Removed) where n = 2 to 10 Another embodiment of the invention provides a novel pyrrolobenzodiazepine having structural formula as shown below, (n = 2) (Formula Removed) Still another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below, (n = 3) (Formula Removed) Still another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below. (n= 4) (Formula Removed) Still another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below. (n= 5) (Formula Removed) Still another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below. (n= 6) (Formula Removed) Still yet another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below. (n= 7) (Formula Removed) Yet another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below. (n= 8) (Formula Removed) Still yet another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below. (n= 9) (Formula Removed) Still yet another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below, (n = 10) (Formula Removed) In an embodiment of the inventioin provides a process for the preparation of analogues of 1, l'-{[(bisalkane-l,N-diyl)piperazine]dioxy}bis(ll aS)-7-methoxy- 1,2,3,1 la-tetrahydro-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one] of formula (VI), the said process comprising steps of: a) reacting compound of formula (I) with 1,2-dibromoethane in water miscible organic solvent in presence of a base at a reflux temperature for a period of 20h to 48h, b) pouring the reaction mixture of step (a) onto water, extracting with ethylacetate separating ethylacetate layer and discarding aqueous layer, c) evaporating the ethylacetate layer of step (b) to obtain a residue which is further purified to obtain pure compound of formula (II), d) providing a solution of formula (II) in a ketonic solvent in presence of a base at a reflux temperature for a period of 20 h to 48 h, e) pouring the reaction mixture of step (d) onto water, extracting with ethylacetate, separating ethylacetate layer, evaporating ethylacetate layer to obtain a residue, purifying the residue to get compound of formula (IV), f) dissolving compound of formula (IV) in alcohol, adding stannous chloride dihydrate, refluxing for 0.5 h to 1.5h, g) adjusting the pH of the reaction mixture of step (f) to 8.0 using alkali bicarbonate solution, h) extracting solution of pH 8.0 of step (g) with ethylacetate, separating ethylacetate extract, drying ethylacetate extract over anhydrous sodium sulphate, filtered and evaporated ethyl acetate solution to yield a crude compound of formula (V), i) dissolving compound of formula (V) of step (h) in a mixture of acetonitrile/water, adding mercuric chloride, mercuric oxide and stirred for 6h to 12 h at an ambient temperature, j) evaporating organic layef of step (i), diluting the residue v tfh ethylacetate, adding saturated bicarbonate solution at room temperature, filtering through celite bed, washed with ethyl acetate to obtain a clear filterate; and k) evaporating filtrate of step (j) to obtain a residue which is purified over silica gel column to yield pure compound of formula (VI). Accordingly,the present invention provides a process for the preparation of compound 1,1'- \|[(bisalkane-l,N-diyl)piperazine]dioxyjbis(l laS)-7-metho.\v-1,2,3,1 la-tetrahydro-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one,characterized in that the said process comprising steps of: (Formula Removed) where n = 2 to 10. a) reacting (25)-N-[4-(2-bromoethoxy)-5-methoxy-2-nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethyl thioacetal with 1,2-dibromoethane in water miscibk organic solvent in presence of a base which is selected from lithium carbonate, sodium carbonate, potassium carbonate or cesium carbonate at a reflux temperature for a period of 20h to 48h, b) pouring the reaction mixture of step (a) onto water, extracting with ethylacetate separating ethylacetate layer and discarding aqueous layer, c) evaporating the ethylacetate layer of step (b) to obtain a residue which is further purified to obt;\ n pure (2S)-N-[4-(2-bromoethoyl)-5-methoxy-2-nitrobenzoyl]pyrrolidine-2 carboxaldehyde diethyl thioacetal. d) providing a solution of (2S)-N-[4-(2-bromoethoxy)-5-methoxy-2-nitrobenzoyl]pyrrolidine-2 carboxaldehyde diethyl thioacetal in a ketonic solvent which is selected from acetone, methyl ethyl ketone and methyl isobutylketone in presence of a base which is selected from lithium carbonate, sodium carbonate, potassium carbonate or cesium carbonate at a reflux temperature for a period of 20 h to 48 h, e) pouring the reaction mixture of step (d) onto water, extracting with ethylacetate, separating ethylacetate layer, evaporating ethylacetate layer to obtain a residue, purifying the residue to get l,l'--\|[(bisbiitane-l.N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy-2-nitrobenzoylpyrrolidin-2-carboxaldehyde diethylthioacetal], . f) dissolvingl,l '-{[(bisbutane-l,N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy-2-nitro benzoylpyrrolidui-2-carboxaldelwde diethylthioaceal] in alcohol which is selected from methanol, ethanol and isopropanol, adding stannous chloride dihydrate, refluxing for 0.5 h to 1.5h, g) adjusting the pH of the reaction mixture of step (f) to 8.0 using alkali bicarbonate solution, h) extracting solution of pH 8.0 of step (g) with ethylacetate, separating ethylacetate extract, drying ethylacetate extract over anhydrous sodium sulphate, filtered and evaporated ethyl acetate solution to yield a crude 1,1-j[(bisbutane-l,N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy-2-nitro benzoylpyrrolidin-2-carboxaldehyde diethylthioacetal] , i) dissolving 1,1'-1[(bisbutane-l,N-diyl)piperazine]dioxy\|bis[(l laS)-7-mefhoxy 2-nitro benzoylpyrrolidiu- carboxaldeh>Je diethylthioacetal, of step (h) in a mixture of acetonitrile/walcr, adding mercuric chloride, mercuric oxide and stirred for 6h to 12 h at an ambient temperature, j) evaporating organic layer of step (i), diluting the residue with ethylacetate. adding saturated bicarbonate solution at room temperature, filtering through celite bed, washed with ethyl acetate to obtain a clear filterate; and k) evaporating filtrate of step (j) to obtain a residue which is purified over silica gel column to yield compoundl,l'-J[(bisalkane-l,N-diyl)piperazine]dioxy} bis( 11 aS)-7-methoxy-l ,2,3,11 a-tetrahydro-5 H-pyrrolo[2.1 -c][\ ,4]benzodiazepin-5-one. Another embodiment of the invention, the base used is selected from a group consisting of lithium carbonate, sodium carbonate, potassium carbonate or cesium carbonate. Another embodiment of the invention the ketonic solvent used is selected from a group consisting of acetone, methyl ethyl ketone and methyl isobutylketone. Another embodiment of the invention the alcohol used is selected from methanol, ethanol and isopropanol, preferably methanol. One more embodiment of the invention provides a pharmaceutical composition useful as anti-tumor agent, said composition comprising an effective amount of one or more analogues of 1, 1'-([(bisalkane-l.N-diyOpiperazineldioxyjbisOlaSVV-methoxy-l^S.lla-tetrahydro-SH-pyrrolo^.l-c][\ ,4]benzodiazepin-5-one] of formula (VI). Still another embodiment the composition optionally comprising ol pharmaceutical^ acceptable additives. Yet another embodiment, the composition is administered to mammals including human beings. Yet another embodiment, the composition may be administered orally, systemically or by any other conventional methods The process for preparation of pyrrolo[2,l-c][l,4]benzodiazepines of formula VI of the drawing accompanying the specification wherein n is 2 to 10 which comprises: reacting (25)-N-[4-hydroxy-5-methoxy-2-nitrobenzoyl]-2-carboxaldehyde diethylthioacetal of formula I with dibromoalkanes in an aprotic water miscible organic solvents like acetone, THF, and DMF in presence of a mild inorganic bases like K2CO3, CSCO3 and BaCO3 upto refluxing temperature for a period up to 48 hours, isolating (2S)-N-[4-(n-bromoalkoxy)-5-methoxy-2-nitrobenzoyl]pyrrolidine-2- carboxaldehyde diethyl thioacetal of formula II with piperazine of formula III in presence of mild inorganic bases like K2CO3, CsCO3 and BaCO3 and in presence of aprotic water miscible organic solvents upto refluxing for a period 48 hours isolating 1,1'-{[(bis alkane-1 ,N-diyl)piperazine]dioxy} bis[( 11 aS)-7-methoxy-2- nitrobenzoylpyrrolidin-2-carbox- aldehyde diethylthioacetal] IV where n is 2-10 by conventional methods, reducing the above nitro compounds of formula IV with SnCl2 .2H2O in presence of organic solvent up to a reflux temperature, isolating the 1,1'- {[(bisalkane-l,N-diyl) piperazine]dioxy}bis[(l laS)-7-methoxy-2- aminobenzoylpyrrolidin-2-carboxaldehyde diethyl thioacetal] of formula V where n is 2-10 by known methods, reacting the above said amino compound of formula V with known deprotecting agents in a conventional manner to give novel pyrrolo[2,l-c][l,4]benzodiazepines of formula VI wherein n are as stated above. The precursor, (2S)-N- (4-hydroxy-2-methoxy-2-nitrobenzoyl) pyrrolidine-2-carboxaldehyde diethyl thioacetal of formula I (intermediates of DC-81) prepared by literature methods (Thurston, D.E.; Murthy, V. S.; Langley, D. R.; Jones, G. B. Synthesis, 1990,81) Some representative compounds of formula VI present invention are given below 1) l,l'-{[(bisethane-l,N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy-l,2,3, lla-tetrahydro-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one]. 2) 1,1'-{[(bispropane-1 ,N-diyl)piperazine]dioxy} bis[( 11 aS)-7-methoxy-1,2,3, lla-tetrahydro-5H-pyirolo[2,l-c][l,4]benzodiazepin-5-one]. 3) l,l'-{[(bisbutane-l,N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy-l,2,3, lla-tetrahydro-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one]. These new analogues of pyrrolo[2,l-c][l,4]benzodiazepinedimers linked at C-8 position through piperazine moiety have shown promising anticancer activity in various cell lines. The molecules synthesized are of immense biological significance with potential sequence selective DNA-binding property. This resulted in design and synthesis of new congeners as illustrated in Scheme-1, which comprise: 1. The ether linkage at C-8 position of DC-81 intermediates with piperazine moiety 2. Refluxmg the reaction mixture for 24-48 h. 3. Synthesis of C-8 linked PBD antitumour antibiotic dimer imines. 4. Purification by column chromatography using different solvents like ethylacetate, hexane, dichloromethane and methanol. The process of preparation of new non-cross linking pyrrolo[2,l-c][l,4]benzodiazepines is disclosed and claimed in applicant's co-pending application no The following examples are given by way of illustration and therefore should not be construed to the present limit of the scope of invention. Brief description of accompanying drawing Figure 1 represents schematic diagram of preparing compound of general formula VI (a-i). Example 1 A solution of (2S)-N-(4-hydroxy-5-methoxy-2-nitrobenzoyl)pyrrolidine-2- carbox-aldehyde diethylthioacetal of formula I (800 mg, 2 mmol), 1, 2-dibromoethane (940 mg, 2.5 mmol) and K.2CO3 (828 mg, 3 mmol) in dry acetone (40 ml) was refluxed for 48h. After the completion of reaction as indicated by TLC, EtOAc- hexane (7:3), the reaction mixture was poured on to the water and then extracted with ethylacetate. Evaporation of the organic layer gave the crude product, which was further purified by column chromatography on silica gel eluting with EtOAc-hexane (1:1) gave the pure (25)-N-[4-(2-bromoethoxy)-5-methoxy-2- nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethyl thioacetal of formula II. "H NMR: (CDCl3) δ 1.20-1.4 (m, 6H), 1.75-2.2 (m, 4H), 2.6-2.9 (m, 4H), 3.20-3.33 (m, 2H), 3.67 (t, 2H), 3.95 (s, 3H); 4.37 (t, 2H), 4.62-4.78 (m, 1H), 4.85 (d, 1H), 6.82 (s, 1H), 7.67 (s, 1H). A solution of (25)-N- [4-(3-bromoethoxy)-5-methoxy-2- nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethylthioacetal of formula II (507 mg, 1 mmol), piperazine(0.043 mg, 0.5 mmol) of the formula III and K2CO3 (414 mg, 3 mmol) in dry acetone (20 ml) was refluxed for 48h. After the completion of reaction as indicated by TLC, EtOAc, the reaction mixture was poured on to the water and then extracted with ethylacetate. Evaporation of the organic layer gave the crude product, which was further purified by column chromatography on silica gel eluting with EtOAc-hexane (9:1) gave the pure l,l'-{ [(bisethane-1,N-diyl)piperazine]dioxy}bis[(l laS)-7-methoxy2-nitro-benzoylpyrrolidin-2-carboxaldehyde diethylthioacetal]. 1H NMR (CDCl3) δ 1.29-1.41 (m, 12H), 1.7-2.39 (m, 8H), 2.60-2.90 (m, 20H), 3.17-3.3 (m, 4H), 3.92 (s, 6H), 4.2 (t, 4H), 4.60-4.70 (m, 2H), 4.8l(d, 2H), 6.8 (s, 2H), 7.7 (s, 2H). FAB MS 939 (M+H)+ The 1,1'- {[(bisethane-1 ,N-diyl)piperazine]dioxy} bis[( 11 a5)-7-methoxy-2-nitro-benzoylpyrroIidin-2-carboxaldehyde diethylthioacetal] IV (939 mg, 1.0 mmol) was dissolved in methanol (10 mL) and added SnCl2.2H2O (1.124 g, 5.0 mmol) was refluxed for 1.5 h. The reaction mixture was then carefully adjusted to pH 8 with saturated NaHCO3 solution and then extracted with ethyl acetate (3x20 mL). The combined organic phase was dried over Na2SO4 and evaporated under vacuum to afford the crude The l,l'-{[(bisethane-l,N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy 2-aminobenzoylpyrrolidin-2-carboxaldehyde diethylthioacetal]. A solution of the 1,l'-{[(bisethane-l,N-diyl)piperazine]dioxy}bis[(lla5)-7-methoxy 2-aminobenzoyIpyrrolidin-2-carboxaldehyde diethylthioacetal] of formula V (879 mg, 1 mmol), HgCl2 (794 mg, 2.93 mmol) and HgO (686 mg, 3.18 mmol) in CH3CN/H2O (3:1, 15 ml) was stirred at room temperature for 12h until TLC (EtOAc), indicates complete loss of starting material. Then organic layer is evaporated in vacuum and the residue is diluted with EtOAc. To this saturated NaHCO3 was added slowly at room temperature and the mixture is filtered through celite and washed with ethylacetate. The filterate is evaporated in vacuum to get crude 1,l'-{[(bisethane-1,N-diyl) piperazine]dioxy}bis[(l laS)-7-methoxy-1,2,3,1 la-tetrahydro-5H-pyrrolo[2,l-c][l,4] benzodiazepin-5-one] of formula VIa, which was further purified by column chromatography on silica gel eluting first with ethylacetate to remove traces of mercuric salts and further eluted with CHCl3-methanol (9:1). 1HNMR (CDCl3) δ 1.92-2.42 (m, 8H), 2.60-2.95 (m, 12H), 3.2-3.88 (m, 6H), 3.92 (s, 6H), 4.14-4.28 (m, 4H), 6.76 (s, 2H), 7.5 (s, 2H), 7.66 (d, 2H). Example 2 A solution of (2S)-N-(4-hydroxy-5-methoxy-2-nitrobenzoyl)pyrrolidine-2- carboxaldehyde diethylthioacetal of formula I (400 mg, 1 mmol), 1,3-dibromopropane (502 mg, 2.5 mmol) and K2CO3 (414 mg, 3 mmol) in dry acetone (20 ml) was refluxed for 48h. After the completion of reaction as indicated by TLC, EtOAc- hexane (7:3), the reaction mixture was poured on to the water and then extracted with ethylacetate. Evaporation of the organic layer gave the crude product, which was further purified by column chromatography on silica gel eluting with EtOAc-hexane (1:1) gave the pure (2S)-N-[4-(4-bromopropoxy)-5-methoxy-2- nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethylthioacetal of formula II. 1H NMR: (CDC13) δ 1.25-1.4 (m, 6H), 1.85-2.35 (m, 4H), 2.38-2.5 (m, 2H), 2.6-2.9 (m, 4H), 3.18-3.33 (m, 2H), 3.64 (t, 2H), 3.97 (s, 3H); 4.29 (t, 2H), 4.67-4.78 (m, 1H), 4.83 (d, 1H), 6.78 (s, 1H), 7.7 (s, 1H). A solution of (25)-N- [4-(4-bromopropoxy)-5-methoxy-2- nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethylthioacetal of formula II (520 mg, 1 mmol), piperazine (0.043 mg, 1 mmol) of the formula III and K2CO3 (414 mg, 3 mmol) in dry acetone (20 ml) was refluxed for 48h. After the completion of reaction as indicated by TLC, EtOAc, the reaction mixture was poured on to the water and then extracted with ethylacetate. Evaporation of the organic layer gave the crude product, which was further purified by column chromatography on silica gel eluting with EtOAc-hexane (9:1) gave the pure of l,l'-{[(bispropane-l,N- diyl)piperazine]dioxy}bis[(l la5)-7-methoxy-2-nitro benzoylpyrrolidin-2- carboxaldehyde diethylthioacetal].formula IV. 1H NMR (CDCl3) δ 1.3-1.42 (m, 12H), 1.9-2.32 (m, 8H), 2.47-2.6 (m, 4H), 2.7-2.9 (m, 24H), 3.2-3.3 (m, 4H), 3.95 (s, 6H), 4.1-4.2 (t, 4H), 4.62-4.75 (m, 2H), 4.82 (d, 2H), 6.75 (s, 2H), 7.67 (s, 2H). FAB MS: 967(M+H)+ The 1,1' - {[(bispropane-1 ,N-diyl)piperazine]dioxy} bis[( 11 aS)-7-methoxy-2-nitro benzoylpyrrolidin-2-carboxaldehyde diethylthioacetal] (966 mg, 1.0 mmol) of the formula IV was dissolved in methanol (10 ml) and added SnCl2.2H20 (1.124 g, 5.0 mmol) was refluxed for 1.5 h. The reaction mixture was then carefully adjusted to pH 8 with saturated NaHCO3 solution and then extracted with ethyl acetate (3x20 ml). The combined organic phase was dried over Na2SO4 and evaporated under vacuum to afford the crude 1,1'-{[(bis propane-l,N-diyl)piperazine]dioxy}bis[(lla5)-7-methoxy 2-aminobenzoylpyrrolidin-2-carboxaldehyde diethylthioacetal].of formula V. A solution of l,l'-{[(bispropane-l,N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy 2- aminobenzoylpyrrolidin-2-carboxaldehyde diethylthioacetal]the formula V. (907 mg, 1 mmol), HgCl2 (794 mg, 2.93 mmol) and HgO (687 mg, 3.18 mmol) in CH3CN/H2O (3:1, 15 ml) was stirred at room temperature for 12h until TLC (EtOAc), indicates complete loss of starting material. Then organic layer is evaporated in vacuum and the residue is diluted with EtOAc. To this saturated NaHCO3 was added slowly at room temperature and the mixture is filtered thorough celite and washed with ethylacetate. The filterate is evaporated in vacuum to get crude l,l'-{[(bispropane-l,N-diyl) piperazine]dioxy}bis[(l laS)-7-methoxy-1,2,3,1 la- tetrahydro-5H-pyrrolo[2,l-c][l,4] benzodiazepin-5-one] of formula VIb, which was further purified by column chromatography on silica gel eluting first with ethylacetate to remove traces of mercuric salts and further eluted with CHCl3-methanol (9:1). 1HNMR1 (CDCl3) δ 1.92-2.37 (m, 8H), 2.57—2.8 (m, 16H), 3.32-3.75 (m, 6H), 3.95 (s, 6H) 4.12-4.45(m, 4H), 6.85 (s, 2H), 7.52 (s, 2H), 7.82 (d, 2H) FAB MS : 659 (M+H)+ Example 3 A solution of (2S)-N-(4-hydroxy-5-methoxy-2-nitrobenzoyl)pyrrolidine-2- carboxaldehyde diethylthioacetal of formula I (400mg, 1 mmol), 1,4-dibromobutane (540 mg, 2.5 mmol) and K2CO3 (414 mg, 3 mmol) in dry acetone (20 ml) was refluxed for 48h. After the completion of reaction as indicated by TLC, EtOAc- hexane (7:3), the reaction mixture was poured on to the water and then extracted with ethylacetate. Evaporation of the organic layer gave the crude product, which was further purified by column chromatography on silica gel eluting with EtOAc-hexane (1:1) gave the pure (2S)-N-[4-(5-bromobutanoxy)-5-methoxy-2- nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethylthioacetal of formula II. 1H NMR: (CDCl3) δ 1.3-1.45(m, 6H), 1.88-2.38 (m, 4H), 2.69-2.88 (m, 8H), 3.20-3.33 (m, 2H), 3.51 (t, 2H), 3.97 (s, 3H); 4.16 (t, 2H), 4.63-4.76 (m, 1H), 4.86(d, 1H), 6.79 (s, 1H), 7.67 (s, 1H). A solution of (2S)-N-[4-(5-bromobutanoxy)-5-methoxy-2- nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethylthioacetal of formula II. (53 mg, 1 mmol), piperazine(0.043 mg, 1 mmol) of formula III and K2CO3 (414 mg, 3 mmol) in dry acetone (20 ml) was refluxed for 48h. After the completion of reaction as indicated by TLC, EtOAc, the reaction mixture was poured on to the water and then extracted with ethylacetate. Evaporation of the organic layer gave the crude product, which was further purified by column chromatography on silica gel eluting with EtOAc-hexane (9:1) gave the pure of l,l'-{[(bisbutane-l,N- diyl)piperazine]dioxy}bis[(l laS)-7-methoxy-2-nitro benzoylpyrrolidin-2- carboxaldehyde diethylthioacetal] of formula IV. 1H NMR (CDC13) δ 1.30-1.43 (m, 12H), 2.74-2.35 (m, 12H), 2.51-2.66 (m, 16H), 3.20-3.3 (m, 4H), 3.97 (s, 6H), 4.12 (t, 4H), 4.64-4.76 (m, 2H), 4.87 (d, 2H), 6.84 (s, 2H), 7.66 (s, 2H). FAB MS: 995 (M+H)+ The of l,l'-{[(bisbutane-l,N-diyl)piperazine]dioxy}bis[(l laS)-7-methoxy-2-nitro benzoylpyrrolidin-2-carboxaldehyde diethylthioacetal].of formula IV (730 mg, 1.0 mmol) was dissolved in methanol (10 ml) and added SnCl2.2H20 (1.124 g, 5.0 mmol) was refluxed for 1.5 h. The reaction mixture was then carefully adjusted to pH 8 with saturated NaHCO3 solution and then extracted with ethyl acetate (3x20 ml). The combined organic phase was dried over Na2SO4 and evaporated under vacuum to afford the crude of l,l'-{[(bisbutane-l,N-diyl) piperazine]dioxy}bis[(l laS)-7-methoxy-2-aminobenzoylpyrrolidin-2-carboxaldehyde diethylthioacetal].of formula V. A solution of l,l'-{[(bisbutane-l,N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy 2-aminobenzoylpyrrolidin-2-carboxaldehyde diethylthioacetal] formula V. (935 mg, 1 mmol), HgCl2 (794 mg, 2.93 mmol) and HgO (687 mg, 3.18 mmol) in CH3CN/H20 (3:1, 15 ml) was stirred at room temperature for 12h until TLC (EtOAc), indicates complete loss of starting material. Then organic layer is evaporated in vacuum and the residue is diluted with EtOAc. To this saturated NaHCO3 was added slowly at room temperature and the mixture is filtered thorough celite and washed with ethylacetate. The filterate is evaporated in vacuum to get crude 1,1'-{[(bisbutane-l,N-diyl) piperazine]dioxy}bis[(lla5)-7-methoxy-l,2,3,l 1 a-tetrahydro-5H-pyrrolo[2,l-c][l,4] benzodiazepin-5-one] Vic, which was further purified by column chromatography on silica gel eluting first with ethylacetate to remove traces of mercuric salts and further eluted with CHCl3-methanol (9:1). 1HNMR (CDCl3) S 1.78-2.24 (m, 8H), 2.30-2.75 (m, 20H), 3.4-3.7 (m, 6H), 3.92 (s, 6H), 4.1-4.23 (m, 4H), 6.73 (s, 2H), 7.48 (s, 2H), 7.60 (d, 2H). FAB MS 687 (M+H)+ Biological Activity: In vitro biological activity studies were carried out at National Cancer Institute (USA). Cytotoxicity: Compounds Vla-d were evaluated in vitro against sixty human tumour cells derived from nine cancer types (leukemia, non-small-cell lung, colon, CNS, melanoma, ovarian, prostate, and breast cancer). For each compound, dose response curves for each cell line were measured at a minimum of five concentrations at 10 fold dilutions. A protocol of 48 h continuous drug exposure was used, and a sulforhodamine B (SRB) protein assay was used to estimate cell viability or growth. The concentration causing 50 % cell growth inhibition (GI50), total cell growth inhibition (TGI, 0% growth) and 50% cell death (LC50, -50% growth) compared with the control was calculated. The mean graph midpoint values of logioTGI and logioLC50 as well as logio GI50 for Vla-d are listed in Table 1. As demonstrated by mean graph pattern, compound Vic exhibits an interesting profile of activity and selectivity for various cell lines. The mean graph mid point of logio TGI and logio LC50 showed similar pattern to the logio GI50 mean graph mid points. Table 1. Logio GI50 logio TGI and logio LC50 mean graphs midpoints (MGMID) of in vitro Cytotoxicity data for the compounds VI a-d against human tumor cell lines. (Table Removed) The in vitro anticancer activity for four representative compounds has been given in Table 2. The comparison of the data of Table 2 reveals the importance of the alkane spacer. As the alkane spacer increased from 2-4 the cytotoxic activity has moderately enhanced. The 4-carbon spacer of compound Vic confers a suitable fit in the minor groove of double helix DNA and show slightly higher activity in this- series of compounds VI a-d. Table 2. Log LC50 (concentration in mol/L causing 50% lethality) Values for Compounds VI a-d (Table Removed) We Claim: 1. A process for the preparation of compound 1,1'-{[(bisalkane-l,N-diyl)piperazine]dioxy}bis(l laS)-7-methoxy-l,2,3,l la-tetrahydro-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one,characterized in that the said process comprising steps of: (Formula Removed) where n = 2 to 10. a) reacting (2S)-N-[4-(2-bromoethoxy)-5-methoxy-2-nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethyl thioacetal with 1,2-dibromoethane in water misciblc organic solvent in presence of a base which is selected from lithium carbonate, sodium carbonate, potassium carbonate or cesium carbonate at a reflux temperature for a period of 20h to 48h, b) pouring the reaction mixture of step (a) onto water, extracting with ethylacetate separating ethylacetate layer and discarding aqueous layer, c) evaporating the ethylacetate layer of step (b) to obtain a residue which is further purified to obtain pure (2S)-N-[4-(2-bromoethoxy)-5-methoxy-2-nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethyl thioacetal, d) providing a solution of (2S)-N-[4-(2-brornoethoxy)-5-methoxy-2-nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethyl thioacetal in a ketonnic solvent which is selected from acetone, methyl ethyl ketone and methyl isobutylketone in presence of a base which is selected from lithium carbonate, sodium carbonate, potassium carbonate or cesium carbonate at a reflux temperature for a period of 20 h to 48 h, e) pouring the reaction mixture of step (d) onto water, extracting with ethylacetate, separating ethylacetate layer, evaporating ethylacetate layer to obtain a residue, purifying the residue to get l,1'-{[(bisbutane-l,N-diyl)piperazine]dioxy\|bis[(l laS)-7-methoxy-2-nitrobenzoylpyrrolidin-2-carboxaldehyde diethylthioacetal], t) dissolving 1,1'- {[(bisbutane-1 ,N-diyl)piperazine]dioxy J bis[( 11 aS)-7-methoxy-2-nitro benzoylpyrrolidin-2-carboxaldehyde diethylthioacetal] in alcohol which is selected from methanol, ethanol and isopropanol, adding stannous chloride dihydrate, refluxing for 0.5 h to 1.5h, g) adjusting the pH of the reaction mixture of step (f) to 8.0 using alkali bicarbonate solution, h) extracting solution of pH 8.0 of step (g) with ethylacetate, separating ethylacetate extract, drying ethylacetate extract over anhydrous sodium sulphate, filtered and evaporated ethyl acetate solution to yield a crude1,1-{[(bisbutane-l,N-diyl)piperazine]dioxy}bis[(11aS)-7-methoxy-2-nitro benzoyIpyrrolidin-2-carboxaldehyde diethylthioacetal] , i) dissolvingl,1'-{[(bisbutane-l,N-diyl)piperazine]dioxy!bis[(llaS)-7-methoxy-2-nitro benzoylpyrrolidin-2-carboxaldehyde diethylthioacetal] of step (h) in a mixture of acetonitrile/water, adding mercuric chloride, mercuric oxide and stirred for 6h to 12 h at an ambient temperature, j) evaporating organic layer of step (i), diluting the residue with ethylacetate. adding saturated bicarbonate solution at room temperature, filtering through celite bed, washed with ethyl acetate to obtain a clear filterate; and k) evaporating filtrate of step (j) to obtain a residue which is purified over silica gel column to yield compound 1,1'-{[(bisalkane-1,N-diyl)piperazine]dioxy!bis(l laS)-7-methoxy-l,2,3,l la-tetrahydro-5H-pyrrolof 2,1 -c][1 ,4]benzodiazepin-5-one. 2. A process of claim 1, wherein the alcohol used is methanol. 3. A process for the preparation of compound 1,1'-{[(bisalkane-1,N-diyl)piperazine]dioxy}bis(l laS)-7-methoxy-1,2,3.1 la-tetrahydro-5H-pyrrolo[2,1-c][l,4]benzodiazepin-5-one as describe herein with reference to examples.

Full Text

A process for the preparation of compoundl,l'-{[(bisalkane-l,N-diyl)piperazine] dioxy}bis(11 aS)-7-methoxy-l ,2,3,11 a-tetrahydro-5H-pyrrolo [2,1 -c\ [l,4|benzodiazepin-5-one
Field of the invention
The present invention relates to novel pyrrolo[2,l-c][l,4]benzodiazepines useful as potential antitumour agents. This invention relates to a process for the preparation of new pyrrolo[2,l-c][l,4]benzodiazepines useful as antitumour agents. More particularly, it provides a process for the preparation of l,l'-|[(bisalkane-l,N-diyl)piperazine]dioxy| bis[(11aS)-7-methoxy-l, 2, 3, 11a-tetrahydro-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one, with aliphatic chain length variations for the compounds and it also describes the anticancer (antitumour) activity. The structural formula of novel pyrrolo[2,l-c][l,4]benzodiazepine is as follows, wherein n = 2 to 10.

(Formula Removed)

Background and Prior art references
Pyrrolo[2,l-c][l,4]benzodiazepines antitumour antibiotics are commonly known as anthramycin class of compounds. In the last few years, a growing interest has been shown in the development of new pyrrolo[2,l-c][l,4]benzodiazepines (PBDs). These antibiotics react covalently with DNA to form an N2-guanine adduct that lies within the minor groove of duplex DNA via an acid-labile aminal bond to the electrophilie imine at the N10-CT1 position. (Kunimoto, S. Masuda, T. Kanbayashi, N. Hamada. M. Naganawa, H. Miyamoto, M. Takeuchi, T. and Unezawa, H. J. Antihiot., 1980, ;o. 665.; Kohn. K.W. and Speous, C.L. J. Mol. Biol, 1970, 51, 551.; Hurley, 1.11 (iairpla, C. and Zmijewski, M. Biochem. Biophys. Acta., 1977, 475, 521.; Kaplan, D..I. and Hurley, L.H. Biochmestry, 1981, 20, 7572). The molecules have a right-handed twist, which allows them to follow the curvature of the minor groove of B-form double-stranded DNA spanning three base pairs. Recently PBD dimers have been developed that comprises two C2-exo-methylene- substituted DC-81 subunits tethered through their C-8 position via an inert propanedioxy linker. (S. J. Ciregson. P. W.Howard, J. A. Hartely, N. A. Brooks, L. J Adams, T. C. Jenkins, L. R.

Kelland, and D. E.Thurston. J.Med.Chem., 2001, 44, 737). A recent development has been the linking of two PBD units through their C-8 positions to give bisfunctional alkylating agents capable of cross-linking DNA (Thurston, D. E. Bose, D. S. Thomson, A. S. Howard, P. W. Leoni, A. Croker, S. J. Jenkins, T. C. Neidle, S. and Hurley, L. H. J. Org. Chem., 1996, 61, 8141-8147). Recently, a noncross-linking mixed imine-amide PBD dimers have been synthesized that have significant DNA binding ability and potent anti tumour activitiy (Kamal, A.; Laxman, N.; Ramesh, G. Ramulu, P and Srinivas, O. US Pat. No. 636233. dt 26-03-2002.; Kamal, A. Ramesh, G.; Laxman, N.; Ramulu, P.; Srinivas, O.; Neelima, K.; Kondapi, A. K. Srinu, V. B.; Nagarajaram, H. M. J. Med. Chem. 2002, 45, 4679 ).
Naturally occurring pyrrolo[2,l-c][l,4]benzodiazepines belong to a group of antitumour antibiotics derived from Streptomyces species. Recently, there is much

(Formula Removed)

impetus for the PBD systems as they can recognize and bind to specific sequence of DNA. Examples of naturally occurring PBD's include anthramycin, DC-81, tomaymycin, sibiromycin and neothramycin.
However, the clinical efficacy for these antibiotics is hindered by several limitations, such as poor water solubility and cardiotoxicity and development of drug resistance and metabolic inactivation.

Objects of the invention
The main object of the present invention is to provide new pyrrolo[2,l-c][l,4]benzodiazepines useful as antitumour agents.
Another object of the invention is to provide pharmaceutical compositions comprising novel pyrrolo[2,1 -c][ 1,4]benzodiazepines useful as anti-cancer agents
Another objective of the present invention is to provide a process for the preparation of novel pyrrolo[2,l-c][l,4] benzodiazepines.. Summary of the invention
Accordingly, the present invention provides novel pyrrolo[2,l-c][l,4]benzodiazepine of formula VI where n is 2 to 10; and a process for the preparation of the same.

(Formula Removed)

Detailed Description of the Invention
In accordance, the present invention provides analogues of 1, l'-{[(bisalkane-1 ,N-diyl)piperazine]dioxy} bis( 11 aS)-7-methoxy-1,2,3,11 a-tetrahydro-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one] of formula (VI)

(Formula Removed)

where n = 2 to 10
Another embodiment of the invention provides a novel pyrrolobenzodiazepine having structural formula as shown below, (n = 2)

(Formula Removed)

Still another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below, (n = 3)

(Formula Removed)

Still another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below. (n= 4)

(Formula Removed)

Still another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below. (n= 5)

(Formula Removed)

Still another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below. (n= 6)

(Formula Removed)

Still yet another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below. (n= 7)
(Formula Removed)

Yet another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below. (n= 8)

(Formula Removed)
Still yet another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below. (n= 9)

(Formula Removed)

Still yet another embodiment, the invention provides novel pyrrolobenzodiazepine having structural formula as shown below, (n = 10)

(Formula Removed)

In an embodiment of the inventioin provides a process for the preparation of
analogues of 1, l'-{[(bisalkane-l,N-diyl)piperazine]dioxy}bis(ll aS)-7-methoxy-
1,2,3,1 la-tetrahydro-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one] of formula (VI), the
said process comprising steps of:
a) reacting compound of formula (I) with 1,2-dibromoethane in water miscible organic solvent in presence of a base at a reflux temperature for a period of 20h to 48h,
b) pouring the reaction mixture of step (a) onto water, extracting with ethylacetate separating ethylacetate layer and discarding aqueous layer,
c) evaporating the ethylacetate layer of step (b) to obtain a residue which is further purified to obtain pure compound of formula (II),
d) providing a solution of formula (II) in a ketonic solvent in presence of a base at a reflux temperature for a period of 20 h to 48 h,
e) pouring the reaction mixture of step (d) onto water, extracting with ethylacetate, separating ethylacetate layer, evaporating ethylacetate layer to obtain a residue, purifying the residue to get compound of formula (IV),
f) dissolving compound of formula (IV) in alcohol, adding stannous chloride dihydrate, refluxing for 0.5 h to 1.5h,

g) adjusting the pH of the reaction mixture of step (f) to 8.0 using alkali
bicarbonate solution, h) extracting solution of pH 8.0 of step (g) with ethylacetate, separating
ethylacetate extract, drying ethylacetate extract over anhydrous sodium
sulphate, filtered and evaporated ethyl acetate solution to yield a crude
compound of formula (V),
i) dissolving compound of formula (V) of step (h) in a mixture of acetonitrile/water, adding mercuric chloride, mercuric oxide and stirred for 6h to 12 h at an ambient temperature,
j) evaporating organic layef of step (i), diluting the residue v tfh ethylacetate, adding saturated bicarbonate solution at room temperature, filtering through celite bed, washed with ethyl acetate to obtain a clear filterate; and
k) evaporating filtrate of step (j) to obtain a residue which is purified over silica gel column to yield pure compound of formula (VI).
Accordingly,the present invention provides a process for the preparation of compound 1,1'- |[(bisalkane-l,N-diyl)piperazine]dioxyjbis(l laS)-7-metho.\v-1,2,3,1 la-tetrahydro-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one,characterized in that the said process comprising steps of:

(Formula Removed)

where n = 2 to 10.
a) reacting (25)-N-[4-(2-bromoethoxy)-5-methoxy-2-nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethyl thioacetal with 1,2-dibromoethane in water miscibk organic solvent in presence of a base which is selected from lithium carbonate, sodium carbonate, potassium carbonate or cesium carbonate at a reflux temperature for a period of 20h to 48h,
b) pouring the reaction mixture of step (a) onto water, extracting with ethylacetate separating ethylacetate layer and discarding aqueous layer,
c) evaporating the ethylacetate layer of step (b) to obtain a residue which is further purified to obt;\ n pure (2S)-N-[4-(2-bromoethoyl)-5-methoxy-2-nitrobenzoyl]pyrrolidine-2 carboxaldehyde diethyl thioacetal.

d) providing a solution of (2S)-N-[4-(2-bromoethoxy)-5-methoxy-2-nitrobenzoyl]pyrrolidine-2 carboxaldehyde diethyl thioacetal in a ketonic solvent which is selected from acetone, methyl ethyl ketone and methyl isobutylketone in presence of a base which is selected from lithium carbonate, sodium carbonate, potassium carbonate or cesium carbonate at a reflux temperature for a period of 20 h to 48 h, e) pouring the reaction mixture of step (d) onto water, extracting with ethylacetate, separating ethylacetate layer, evaporating ethylacetate layer to obtain a residue, purifying the residue to get l,l'--|[(bisbiitane-l.N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy-2-nitrobenzoylpyrrolidin-2-carboxaldehyde diethylthioacetal],
. f) dissolvingl,l '-{[(bisbutane-l,N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy-2-nitro benzoylpyrrolidui-2-carboxaldelwde diethylthioaceal] in alcohol which is selected from methanol, ethanol and isopropanol, adding stannous chloride dihydrate, refluxing for 0.5 h to 1.5h,
g) adjusting the pH of the reaction mixture of step (f) to 8.0 using alkali bicarbonate solution,
h) extracting solution of pH 8.0 of step (g) with ethylacetate, separating ethylacetate extract, drying ethylacetate extract over anhydrous sodium sulphate, filtered and evaporated ethyl acetate solution to yield a crude 1,1-j[(bisbutane-l,N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy-2-nitro benzoylpyrrolidin-2-carboxaldehyde diethylthioacetal] ,
i) dissolving 1,1'-1[(bisbutane-l,N-diyl)piperazine]dioxy|bis[(l laS)-7-mefhoxy 2-nitro benzoylpyrrolidiu- carboxaldeh>Je diethylthioacetal, of step (h) in a mixture of acetonitrile/walcr, adding mercuric chloride, mercuric oxide and stirred for 6h to 12 h at an ambient temperature,
j) evaporating organic layer of step (i), diluting the residue with ethylacetate. adding saturated bicarbonate solution at room temperature, filtering through celite bed, washed with ethyl acetate to obtain a clear filterate; and
k) evaporating filtrate of step (j) to obtain a residue which is purified over silica gel column to yield compoundl,l'-J[(bisalkane-l,N-diyl)piperazine]dioxy} bis( 11 aS)-7-methoxy-l ,2,3,11 a-tetrahydro-5 H-pyrrolo[2.1 -c][\ ,4]benzodiazepin-5-one.

Another embodiment of the invention, the base used is selected from a group consisting of lithium carbonate, sodium carbonate, potassium carbonate or cesium carbonate.
Another embodiment of the invention the ketonic solvent used is selected from a group consisting of acetone, methyl ethyl ketone and methyl isobutylketone.
Another embodiment of the invention the alcohol used is selected from methanol, ethanol and isopropanol, preferably methanol.
One more embodiment of the invention provides a pharmaceutical composition useful as anti-tumor agent, said composition comprising an effective amount of one or more analogues of 1, 1'-([(bisalkane-l.N-diyOpiperazineldioxyjbisOlaSVV-methoxy-l^S.lla-tetrahydro-SH-pyrrolo^.l-c][\ ,4]benzodiazepin-5-one] of formula (VI).
Still another embodiment the composition optionally comprising ol pharmaceutical^ acceptable additives.
Yet another embodiment, the composition is administered to mammals including human beings.
Yet another embodiment, the composition may be administered orally, systemically or by any other conventional methods

The process for preparation of pyrrolo[2,l-c][l,4]benzodiazepines of formula
VI of the drawing accompanying the specification wherein n is 2 to 10 which
comprises: reacting (25)-N-[4-hydroxy-5-methoxy-2-nitrobenzoyl]-2-carboxaldehyde
diethylthioacetal of formula I with dibromoalkanes in an aprotic water miscible
organic solvents like acetone, THF, and DMF in presence of a mild inorganic bases
like K2CO3, CSCO3 and BaCO3 upto refluxing temperature for a period up to 48
hours, isolating (2S)-N-[4-(n-bromoalkoxy)-5-methoxy-2-nitrobenzoyl]pyrrolidine-2-
carboxaldehyde diethyl thioacetal of formula II with piperazine of formula III in
presence of mild inorganic bases like K2CO3, CsCO3 and BaCO3 and in presence of
aprotic water miscible organic solvents upto refluxing for a period 48 hours isolating
1,1'-{[(bis alkane-1 ,N-diyl)piperazine]dioxy} bis[( 11 aS)-7-methoxy-2-
nitrobenzoylpyrrolidin-2-carbox- aldehyde diethylthioacetal] IV where n is 2-10 by
conventional methods, reducing the above nitro compounds of formula IV with SnCl2
.2H2O in presence of organic solvent up to a reflux temperature, isolating the 1,1'-
{[(bisalkane-l,N-diyl) piperazine]dioxy}bis[(l laS)-7-methoxy-2-
aminobenzoylpyrrolidin-2-carboxaldehyde diethyl thioacetal] of formula V where n is 2-10 by known methods, reacting the above said amino compound of formula V with known deprotecting agents in a conventional manner to give novel pyrrolo[2,l-c][l,4]benzodiazepines of formula VI wherein n are as stated above.
The precursor, (2S)-N- (4-hydroxy-2-methoxy-2-nitrobenzoyl) pyrrolidine-2-carboxaldehyde diethyl thioacetal of formula I (intermediates of DC-81) prepared by literature methods (Thurston, D.E.; Murthy, V. S.; Langley, D. R.; Jones, G. B. Synthesis, 1990,81)
Some representative compounds of formula VI present invention are given below
1) l,l'-{[(bisethane-l,N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy-l,2,3, lla-tetrahydro-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one].
2) 1,1'-{[(bispropane-1 ,N-diyl)piperazine]dioxy} bis[( 11 aS)-7-methoxy-1,2,3, lla-tetrahydro-5H-pyirolo[2,l-c][l,4]benzodiazepin-5-one].
3) l,l'-{[(bisbutane-l,N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy-l,2,3, lla-tetrahydro-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one].
These new analogues of pyrrolo[2,l-c][l,4]benzodiazepinedimers linked at C-8 position through piperazine moiety have shown promising anticancer activity in

various cell lines. The molecules synthesized are of immense biological significance with potential sequence selective DNA-binding property. This resulted in design and synthesis of new congeners as illustrated in Scheme-1, which comprise:
1. The ether linkage at C-8 position of DC-81 intermediates with piperazine moiety
2. Refluxmg the reaction mixture for 24-48 h.
3. Synthesis of C-8 linked PBD antitumour antibiotic dimer imines.
4. Purification by column chromatography using different solvents like ethylacetate, hexane, dichloromethane and methanol.
The process of preparation of new non-cross linking pyrrolo[2,l-c][l,4]benzodiazepines is disclosed and claimed in applicant's co-pending application
no
The following examples are given by way of illustration and therefore should not be
construed to the present limit of the scope of invention.
Brief description of accompanying drawing
Figure 1 represents schematic diagram of preparing compound of general formula VI
(a-i).
Example 1
A solution of (2S)-N-(4-hydroxy-5-methoxy-2-nitrobenzoyl)pyrrolidine-2-
carbox-aldehyde diethylthioacetal of formula I (800 mg, 2 mmol), 1, 2-dibromoethane
(940 mg, 2.5 mmol) and K.2CO3 (828 mg, 3 mmol) in dry acetone (40 ml) was
refluxed for 48h. After the completion of reaction as indicated by TLC, EtOAc-
hexane (7:3), the reaction mixture was poured on to the water and then extracted with
ethylacetate. Evaporation of the organic layer gave the crude product, which was
further purified by column chromatography on silica gel eluting with EtOAc-hexane
(1:1) gave the pure (25)-N-[4-(2-bromoethoxy)-5-methoxy-2-
nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethyl thioacetal of formula II.
"H NMR: (CDCl3) δ 1.20-1.4 (m, 6H), 1.75-2.2 (m, 4H), 2.6-2.9 (m, 4H), 3.20-3.33 (m, 2H), 3.67 (t, 2H), 3.95 (s, 3H); 4.37 (t, 2H), 4.62-4.78 (m, 1H), 4.85 (d, 1H), 6.82 (s, 1H), 7.67 (s, 1H).
A solution of (25)-N- [4-(3-bromoethoxy)-5-methoxy-2-
nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethylthioacetal of formula II (507 mg, 1 mmol), piperazine(0.043 mg, 0.5 mmol) of the formula III and K2CO3 (414 mg, 3

mmol) in dry acetone (20 ml) was refluxed for 48h. After the completion of reaction as indicated by TLC, EtOAc, the reaction mixture was poured on to the water and then extracted with ethylacetate. Evaporation of the organic layer gave the crude product, which was further purified by column chromatography on silica gel eluting with EtOAc-hexane (9:1) gave the pure l,l'-{ [(bisethane-1,N-diyl)piperazine]dioxy}bis[(l laS)-7-methoxy2-nitro-benzoylpyrrolidin-2-carboxaldehyde diethylthioacetal].
1H NMR (CDCl3) δ 1.29-1.41 (m, 12H), 1.7-2.39 (m, 8H), 2.60-2.90 (m, 20H), 3.17-3.3 (m, 4H), 3.92 (s, 6H), 4.2 (t, 4H), 4.60-4.70 (m, 2H), 4.8l(d, 2H), 6.8 (s, 2H), 7.7 (s, 2H). FAB MS 939 (M+H)+
The 1,1'- {[(bisethane-1 ,N-diyl)piperazine]dioxy} bis[( 11 a5)-7-methoxy-2-nitro-benzoylpyrroIidin-2-carboxaldehyde diethylthioacetal] IV (939 mg, 1.0 mmol) was dissolved in methanol (10 mL) and added SnCl2.2H2O (1.124 g, 5.0 mmol) was refluxed for 1.5 h. The reaction mixture was then carefully adjusted to pH 8 with saturated NaHCO3 solution and then extracted with ethyl acetate (3x20 mL). The combined organic phase was dried over Na2SO4 and evaporated under vacuum to afford the crude The l,l'-{[(bisethane-l,N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy 2-aminobenzoylpyrrolidin-2-carboxaldehyde diethylthioacetal].
A solution of the 1,l'-{[(bisethane-l,N-diyl)piperazine]dioxy}bis[(lla5)-7-methoxy 2-aminobenzoyIpyrrolidin-2-carboxaldehyde diethylthioacetal] of formula V (879 mg, 1 mmol), HgCl2 (794 mg, 2.93 mmol) and HgO (686 mg, 3.18 mmol) in CH3CN/H2O (3:1, 15 ml) was stirred at room temperature for 12h until TLC (EtOAc), indicates complete loss of starting material. Then organic layer is evaporated in vacuum and the residue is diluted with EtOAc. To this saturated NaHCO3 was added slowly at room temperature and the mixture is filtered through celite and washed with ethylacetate. The filterate is evaporated in vacuum to get crude 1,l'-{[(bisethane-1,N-diyl) piperazine]dioxy}bis[(l laS)-7-methoxy-1,2,3,1 la-tetrahydro-5H-pyrrolo[2,l-c][l,4] benzodiazepin-5-one] of formula VIa, which was further purified by column chromatography on silica gel eluting first with ethylacetate to remove traces of mercuric salts and further eluted with CHCl3-methanol (9:1).
1HNMR (CDCl3) δ 1.92-2.42 (m, 8H), 2.60-2.95 (m, 12H), 3.2-3.88 (m, 6H), 3.92 (s, 6H), 4.14-4.28 (m, 4H), 6.76 (s, 2H), 7.5 (s, 2H), 7.66 (d, 2H).

Example 2
A solution of (2S)-N-(4-hydroxy-5-methoxy-2-nitrobenzoyl)pyrrolidine-2-
carboxaldehyde diethylthioacetal of formula I (400 mg, 1 mmol), 1,3-dibromopropane
(502 mg, 2.5 mmol) and K2CO3 (414 mg, 3 mmol) in dry acetone (20 ml) was
refluxed for 48h. After the completion of reaction as indicated by TLC, EtOAc-
hexane (7:3), the reaction mixture was poured on to the water and then extracted with
ethylacetate. Evaporation of the organic layer gave the crude product, which was
further purified by column chromatography on silica gel eluting with EtOAc-hexane
(1:1) gave the pure (2S)-N-[4-(4-bromopropoxy)-5-methoxy-2-
nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethylthioacetal of formula II. 1H NMR: (CDC13) δ 1.25-1.4 (m, 6H), 1.85-2.35 (m, 4H), 2.38-2.5 (m, 2H), 2.6-2.9 (m, 4H), 3.18-3.33 (m, 2H), 3.64 (t, 2H), 3.97 (s, 3H); 4.29 (t, 2H), 4.67-4.78 (m, 1H), 4.83 (d, 1H), 6.78 (s, 1H), 7.7 (s, 1H).
A solution of (25)-N- [4-(4-bromopropoxy)-5-methoxy-2-
nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethylthioacetal of formula II (520 mg, 1
mmol), piperazine (0.043 mg, 1 mmol) of the formula III and K2CO3 (414 mg, 3
mmol) in dry acetone (20 ml) was refluxed for 48h. After the completion of reaction
as indicated by TLC, EtOAc, the reaction mixture was poured on to the water and
then extracted with ethylacetate. Evaporation of the organic layer gave the crude
product, which was further purified by column chromatography on silica gel eluting
with EtOAc-hexane (9:1) gave the pure of l,l'-{[(bispropane-l,N-
diyl)piperazine]dioxy}bis[(l la5)-7-methoxy-2-nitro benzoylpyrrolidin-2-
carboxaldehyde diethylthioacetal].formula IV.
1H NMR (CDCl3) δ 1.3-1.42 (m, 12H), 1.9-2.32 (m, 8H), 2.47-2.6 (m, 4H), 2.7-2.9 (m, 24H), 3.2-3.3 (m, 4H), 3.95 (s, 6H), 4.1-4.2 (t, 4H), 4.62-4.75 (m, 2H), 4.82 (d, 2H), 6.75 (s, 2H), 7.67 (s, 2H). FAB MS: 967(M+H)+
The 1,1' - {[(bispropane-1 ,N-diyl)piperazine]dioxy} bis[( 11 aS)-7-methoxy-2-nitro benzoylpyrrolidin-2-carboxaldehyde diethylthioacetal] (966 mg, 1.0 mmol) of the formula IV was dissolved in methanol (10 ml) and added SnCl2.2H20 (1.124 g, 5.0 mmol) was refluxed for 1.5 h. The reaction mixture was then carefully adjusted to pH 8 with saturated NaHCO3 solution and then extracted with ethyl acetate (3x20 ml).

The combined organic phase was dried over Na2SO4 and evaporated under vacuum to
afford the crude 1,1'-{[(bis propane-l,N-diyl)piperazine]dioxy}bis[(lla5)-7-methoxy
2-aminobenzoylpyrrolidin-2-carboxaldehyde diethylthioacetal].of formula V.
A solution of l,l'-{[(bispropane-l,N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy 2-
aminobenzoylpyrrolidin-2-carboxaldehyde diethylthioacetal]the formula V. (907 mg,
1 mmol), HgCl2 (794 mg, 2.93 mmol) and HgO (687 mg, 3.18 mmol) in
CH3CN/H2O (3:1, 15 ml) was stirred at room temperature for 12h until TLC
(EtOAc), indicates complete loss of starting material. Then organic layer is
evaporated in vacuum and the residue is diluted with EtOAc. To this saturated
NaHCO3 was added slowly at room temperature and the mixture is filtered thorough
celite and washed with ethylacetate. The filterate is evaporated in vacuum to get crude
l,l'-{[(bispropane-l,N-diyl) piperazine]dioxy}bis[(l laS)-7-methoxy-1,2,3,1 la-
tetrahydro-5H-pyrrolo[2,l-c][l,4] benzodiazepin-5-one] of formula VIb, which was further purified by column chromatography on silica gel eluting first with ethylacetate to remove traces of mercuric salts and further eluted with CHCl3-methanol (9:1). 1HNMR1 (CDCl3) δ 1.92-2.37 (m, 8H), 2.57—2.8 (m, 16H), 3.32-3.75 (m, 6H), 3.95 (s, 6H) 4.12-4.45(m, 4H), 6.85 (s, 2H), 7.52 (s, 2H), 7.82 (d, 2H) FAB MS : 659 (M+H)+
Example 3
A solution of (2S)-N-(4-hydroxy-5-methoxy-2-nitrobenzoyl)pyrrolidine-2-
carboxaldehyde diethylthioacetal of formula I (400mg, 1 mmol), 1,4-dibromobutane
(540 mg, 2.5 mmol) and K2CO3 (414 mg, 3 mmol) in dry acetone (20 ml) was
refluxed for 48h. After the completion of reaction as indicated by TLC, EtOAc-
hexane (7:3), the reaction mixture was poured on to the water and then extracted with
ethylacetate. Evaporation of the organic layer gave the crude product, which was
further purified by column chromatography on silica gel eluting with EtOAc-hexane
(1:1) gave the pure (2S)-N-[4-(5-bromobutanoxy)-5-methoxy-2-
nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethylthioacetal of formula II. 1H NMR: (CDCl3) δ 1.3-1.45(m, 6H), 1.88-2.38 (m, 4H), 2.69-2.88 (m, 8H), 3.20-3.33 (m, 2H), 3.51 (t, 2H), 3.97 (s, 3H); 4.16 (t, 2H), 4.63-4.76 (m, 1H), 4.86(d, 1H), 6.79 (s, 1H), 7.67 (s, 1H).
A solution of (2S)-N-[4-(5-bromobutanoxy)-5-methoxy-2-
nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethylthioacetal of formula II. (53 mg, 1

mmol), piperazine(0.043 mg, 1 mmol) of formula III and K2CO3 (414 mg, 3 mmol) in
dry acetone (20 ml) was refluxed for 48h. After the completion of reaction as
indicated by TLC, EtOAc, the reaction mixture was poured on to the water and then
extracted with ethylacetate. Evaporation of the organic layer gave the crude product,
which was further purified by column chromatography on silica gel eluting with
EtOAc-hexane (9:1) gave the pure of l,l'-{[(bisbutane-l,N-
diyl)piperazine]dioxy}bis[(l laS)-7-methoxy-2-nitro benzoylpyrrolidin-2-
carboxaldehyde diethylthioacetal] of formula IV.
1H NMR (CDC13) δ 1.30-1.43 (m, 12H), 2.74-2.35 (m, 12H), 2.51-2.66 (m, 16H), 3.20-3.3 (m, 4H), 3.97 (s, 6H), 4.12 (t, 4H), 4.64-4.76 (m, 2H), 4.87 (d, 2H), 6.84 (s, 2H), 7.66 (s, 2H). FAB MS: 995 (M+H)+
The of l,l'-{[(bisbutane-l,N-diyl)piperazine]dioxy}bis[(l laS)-7-methoxy-2-nitro benzoylpyrrolidin-2-carboxaldehyde diethylthioacetal].of formula IV (730 mg, 1.0 mmol) was dissolved in methanol (10 ml) and added SnCl2.2H20 (1.124 g, 5.0 mmol) was refluxed for 1.5 h. The reaction mixture was then carefully adjusted to pH 8 with saturated NaHCO3 solution and then extracted with ethyl acetate (3x20 ml). The combined organic phase was dried over Na2SO4 and evaporated under vacuum to afford the crude of l,l'-{[(bisbutane-l,N-diyl) piperazine]dioxy}bis[(l laS)-7-methoxy-2-aminobenzoylpyrrolidin-2-carboxaldehyde diethylthioacetal].of formula V.
A solution of l,l'-{[(bisbutane-l,N-diyl)piperazine]dioxy}bis[(llaS)-7-methoxy 2-aminobenzoylpyrrolidin-2-carboxaldehyde diethylthioacetal] formula V. (935 mg, 1 mmol), HgCl2 (794 mg, 2.93 mmol) and HgO (687 mg, 3.18 mmol) in CH3CN/H20 (3:1, 15 ml) was stirred at room temperature for 12h until TLC (EtOAc), indicates complete loss of starting material. Then organic layer is evaporated in vacuum and the residue is diluted with EtOAc. To this saturated NaHCO3 was added slowly at room temperature and the mixture is filtered thorough celite and washed with ethylacetate. The filterate is evaporated in vacuum to get crude 1,1'-{[(bisbutane-l,N-diyl) piperazine]dioxy}bis[(lla5)-7-methoxy-l,2,3,l 1 a-tetrahydro-5H-pyrrolo[2,l-c][l,4] benzodiazepin-5-one] Vic, which was further purified by column chromatography on silica gel eluting first with ethylacetate to remove traces of mercuric salts and further eluted with CHCl3-methanol (9:1).

1HNMR (CDCl3) S 1.78-2.24 (m, 8H), 2.30-2.75 (m, 20H), 3.4-3.7 (m, 6H), 3.92 (s, 6H), 4.1-4.23 (m, 4H), 6.73 (s, 2H), 7.48 (s, 2H), 7.60 (d, 2H). FAB MS 687 (M+H)+
Biological Activity: In vitro biological activity studies were carried out at National Cancer Institute (USA).
Cytotoxicity: Compounds Vla-d were evaluated in vitro against sixty human tumour
cells derived from nine cancer types (leukemia, non-small-cell lung, colon, CNS,
melanoma, ovarian, prostate, and breast cancer). For each compound, dose response
curves for each cell line were measured at a minimum of five concentrations at 10
fold dilutions. A protocol of 48 h continuous drug exposure was used, and a
sulforhodamine B (SRB) protein assay was used to estimate cell viability or growth.
The concentration causing 50 % cell growth inhibition (GI50), total cell growth
inhibition (TGI, 0% growth) and 50% cell death (LC50, -50% growth) compared with
the control was calculated. The mean graph midpoint values of logioTGI and
logioLC50 as well as logio GI50 for Vla-d are listed in Table 1. As demonstrated by
mean graph pattern, compound Vic exhibits an interesting profile of activity and
selectivity for various cell lines. The mean graph mid point of logio TGI and logio
LC50 showed similar pattern to the logio GI50 mean graph mid points.
Table 1. Logio GI50 logio TGI and logio LC50 mean graphs midpoints (MGMID) of
in vitro Cytotoxicity data for the compounds VI a-d against human tumor cell lines.

(Table Removed)

The in vitro anticancer activity for four representative compounds has been given in
Table 2. The comparison of the data of Table 2 reveals the importance of the alkane
spacer. As the alkane spacer increased from 2-4 the cytotoxic activity has moderately
enhanced. The 4-carbon spacer of compound Vic confers a suitable fit in the minor
groove of double helix DNA and show slightly higher activity in this- series of
compounds VI a-d.
Table 2. Log LC50 (concentration in mol/L causing 50% lethality) Values for Compounds VI a-d
(Table Removed)

We Claim:
1. A process for the preparation of compound 1,1'-{[(bisalkane-l,N-diyl)piperazine]dioxy}bis(l laS)-7-methoxy-l,2,3,l la-tetrahydro-5H-pyrrolo[2,l-c][l,4]benzodiazepin-5-one,characterized in that the said process comprising steps of:

(Formula Removed)
where n = 2 to 10.
a) reacting (2S)-N-[4-(2-bromoethoxy)-5-methoxy-2-nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethyl thioacetal with 1,2-dibromoethane in water misciblc organic solvent in presence of a base which is selected from lithium carbonate, sodium carbonate, potassium carbonate or cesium carbonate at a reflux temperature for a period of 20h to 48h,
b) pouring the reaction mixture of step (a) onto water, extracting with ethylacetate separating ethylacetate layer and discarding aqueous layer,
c) evaporating the ethylacetate layer of step (b) to obtain a residue which is further purified to obtain pure (2S)-N-[4-(2-bromoethoxy)-5-methoxy-2-nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethyl thioacetal,
d) providing a solution of (2S)-N-[4-(2-brornoethoxy)-5-methoxy-2-nitrobenzoyl]pyrrolidine-2-carboxaldehyde diethyl thioacetal in a ketonnic solvent which is selected from acetone, methyl ethyl ketone and methyl isobutylketone in presence of a base which is selected from lithium carbonate, sodium carbonate, potassium carbonate or cesium carbonate at a reflux temperature for a period of 20 h to 48 h,
e) pouring the reaction mixture of step (d) onto water, extracting with ethylacetate, separating ethylacetate layer, evaporating ethylacetate layer to obtain a residue, purifying the residue to get l,1'-{[(bisbutane-l,N-diyl)piperazine]dioxy|bis[(l laS)-7-methoxy-2-nitrobenzoylpyrrolidin-2-carboxaldehyde diethylthioacetal],
t) dissolving 1,1'- {[(bisbutane-1 ,N-diyl)piperazine]dioxy J bis[( 11 aS)-7-methoxy-2-nitro benzoylpyrrolidin-2-carboxaldehyde diethylthioacetal] in alcohol

which is selected from methanol, ethanol and isopropanol, adding stannous chloride dihydrate, refluxing for 0.5 h to 1.5h,
g) adjusting the pH of the reaction mixture of step (f) to 8.0 using alkali bicarbonate solution,
h) extracting solution of pH 8.0 of step (g) with ethylacetate, separating ethylacetate extract, drying ethylacetate extract over anhydrous sodium sulphate, filtered and evaporated ethyl acetate solution to yield a crude1,1-{[(bisbutane-l,N-diyl)piperazine]dioxy}bis[(11aS)-7-methoxy-2-nitro benzoyIpyrrolidin-2-carboxaldehyde diethylthioacetal] ,
i) dissolvingl,1'-{[(bisbutane-l,N-diyl)piperazine]dioxy!bis[(llaS)-7-methoxy-2-nitro benzoylpyrrolidin-2-carboxaldehyde diethylthioacetal] of step (h) in a mixture of acetonitrile/water, adding mercuric chloride, mercuric oxide and stirred for 6h to 12 h at an ambient temperature,
j) evaporating organic layer of step (i), diluting the residue with ethylacetate. adding saturated bicarbonate solution at room temperature, filtering through celite bed, washed with ethyl acetate to obtain a clear filterate; and
k) evaporating filtrate of step (j) to obtain a residue which is purified over silica gel column to yield compound 1,1'-{[(bisalkane-1,N-diyl)piperazine]dioxy!bis(l laS)-7-methoxy-l,2,3,l la-tetrahydro-5H-pyrrolof 2,1 -c][1 ,4]benzodiazepin-5-one.
2. A process of claim 1, wherein the alcohol used is methanol.
3. A process for the preparation of compound 1,1'-{[(bisalkane-1,N-diyl)piperazine]dioxy}bis(l laS)-7-methoxy-1,2,3.1 la-tetrahydro-5H-pyrrolo[2,1-c][l,4]benzodiazepin-5-one as describe herein with reference to examples.

Documents:

2980-DELNP-2004-Abstract-(04-02-2009).pdf

2980-DELNP-2004-Abstract-(15-12-2008).pdf

2980-delnp-2004-abstract.pdf

2980-DELNP-2004-Claims-(04-02-2009).pdf

2980-DELNP-2004-Claims-(15-12-2008).pdf

2980-delnp-2004-claims.pdf

2980-delnp-2004-complete specification (granted).pdf

2980-DELNP-2004-Correspondence-Others-(04-02-2009).pdf

2980-DELNP-2004-Correspondence-Others-(15-12-2008).pdf

2980-DELNP-2004-Correspondence-Others-(18-12-2008).pdf

2980-delnp-2004-correspondence-others.pdf

2980-DELNP-2004-Description (Complete)-(04-02-2009).pdf

2980-delnp-2004-description (complete).pdf

2980-delnp-2004-drawings.pdf

2980-delnp-2004-form-1.pdf

2980-delnp-2004-form-18.pdf

2980-DELNP-2004-Form-2-(04-02-2009).pdf

2980-DELNP-2004-Form-2-(15-12-2008).pdf

2980-delnp-2004-form-2.pdf

2980-DELNP-2004-Form-3-(15-12-2008).pdf

2980-delnp-2004-form-3.pdf

2980-delnp-2004-form-5.pdf

2980-DELNP-2004-Petition-137-(15-12-2008).pdf

abstract.jpg

« Previous Patent

Next Patent »

Patent Number

231500

Indian Patent Application Number

2980/DELNP/2004

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

05-Mar-2009

Date of Filing

30-Sep-2004

Name of Patentee

COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110 001,INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	AHMED KAMAL	INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY,HYDERABAD,INDIA.
2	PERAM SURAKATTULA MURALI MOHAN REDDY	INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY,HYDERABAD,INDIA.
3	DEPATLA RAJASEKHAR REDDY	INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY,HYDERABAD,INDIA.

PCT International Classification Number

C 7D 243/14

PCT International Application Number

PCT/IB03/01164

PCT International Filing date

2003-03-31

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA