Title of Invention	A PROCESS FOR THE PREPARATION OF NOVEL CHIRAL SALEN TRANSITION METAL CATALYST USEFUL IN ENANTIOSELECTIVE EPOXIDATION OF PROCHIRAL OLEFINS
Abstract	An improved process for the preparation of chiral SALEN transition metal catalyst useful in enantioselective epoxidation of prochiral olefins of formula (1) where R1-R8 are independently represent H, alkyl, halogen, A-B-A chirally pure 1,2 diamine, M= transition metal ion and Y= halide perchlorate, hexafluorophosphate were synthesised and used as chiral catalyst for enantioselective epoxidation of styrene, indene and chromenes with high epoxide conversion (>99%) and ee"s (35->99%) within 1-6 hours using cheaper oxidant like sodium hypochlorite.

Title of Invention

A PROCESS FOR THE PREPARATION OF NOVEL CHIRAL SALEN TRANSITION METAL CATALYST USEFUL IN ENANTIOSELECTIVE EPOXIDATION OF PROCHIRAL OLEFINS

Abstract

An improved process for the preparation of chiral SALEN transition metal catalyst useful in enantioselective epoxidation of prochiral olefins of formula (1) where R1-R8 are independently represent H, alkyl, halogen, A-B-A chirally pure 1,2 diamine, M= transition metal ion and Y= halide perchlorate, hexafluorophosphate were synthesised and used as chiral catalyst for enantioselective epoxidation of styrene, indene and chromenes with high epoxide conversion (>99%) and ee"s (35->99%) within 1-6 hours using cheaper oxidant like sodium hypochlorite.

Full Text	The present invention relates to a process for the preparation of novel chiral SALEN transition metal catalyst useful in enantioselective epoxidation of prochiral olefins. The chirally enriched epoxides are important intermediates in the synthesis of optically active medicines, including 6-cyano-2,2-dimethylbenzopyran, indene and styrene oxides also ecofriendly pest control agents and flavors. Enantioselective catalytic epoxidation of non-functionalised alkenes has emerged as a powerful tool for the synthesis of chirally enriched epoxides required as intermediates for chiral building blocks in the preparation of complex optically pure bio-active compounds. Several chiral drugs, viz., Crixivan (an HIV protease inhibitor), Cromakalim (a highly potent antihypertensive), Tetramisol ((5) form is a powerful anthelmintic) and many more under trial and developmental stage utilize optically pure epoxides as the key intermediate as reviewed by N. Collins, G. N. Sheldrake, J. Crossby (Eds), Chirality in Industry; The Commercial Manufacture and Application of Optically active Compound, Wiley, New Yorl, 1995; R. E. Gawley and J. Aube Principles of Asymmetric Synthesis, Ed. by J. E. Baldwin, Pergamon publication Chapter 8 Oxidation pp. 325 ; E. N. Jacobsen, In catalytic asymmetric synthesis, Ed. by Ojima, I. VCH publication, 1993. pp. 59. Among functionalised alkenes, Sharpless asymmetric epoxidation of allylic alcohols has emerged as one of the most widely applied reactions in asymmetric synthesis using titanium tartrate in presence of tert-butyl hydroperoxide as oxidant showing highest enantioselectivity. (R. A. Johnson and K. B. Sharpless, In catalytic asymmetric synthesis, Ed. by Ojima, I. VCH publication, 1993. pp. 103). This method requires pre-coordinating functional group on the substrate, in absence of which the method is no more enantioselective. Since many drug and agrochemical intermediates require epoxides of non-functionalised alkenes, this method is of little use for this purpose. Bolm, C., in Angew. Chem. Int. Ed. Eng. 1991, 30, 403 has reviewed the enantioselective epoxidation catalysis. Central idea of the research in this area has been to achieve high enantioselectivity in the epoxidation of alkenes bearing no functionality require for precoordination to the catalyst. Their selectivity is determined solely through non bonded interactions. Hence, transition metals catalysts emerged as the most preferred strategy to accomplish this task. These catalysts can utilize a range of oxidants namely, molecular oxygen, lodosyl arenes, sodium hypochlorite, hydrogen peroxide, mono persulphates and alkyl hydroperoxide. It is likely that these catalysts will be oxo transfer agents analogous to Cytochrome P-450 class of heme containing proteins. Groves' land mark discovery of iron (III) porphyrin complexes models was the first successful step towards synthetic model of Cytochrome P-450. Since then many fascinating and sophisticated porphyrins have been synthesized which include Basket handle, Twin Coronet porphyrins, Picnic Basket derivatives, Strapped porphyrins, D4 symmetric metalloporphyrins (Me Murry, T. J., Groves, J. T., Cytochrome P-450, Ortiz deMontellano, PR (Ed.) Polonium, New York 1986, Chapter 1). Although high turnover numbers have been observed (more than 3000) with maximum enantioselection up to 76 % enantiomeric excess (ee's) was obtained for cis-ß methyl styrene, the synthesis of these porphyrins is very complicated. It involves multi step synthesis and requires many anhydrous and inert reaction conditions. Not withstanding multi step, yields are very low hence, these routes are of little commercial value. In the last decades non-porphyrin based processes have been developed for asymmetric epoxidation of non-functionalised alkenes that employ an optically active manganese complex as an asymmetric catalyst. These processes are attracting attention because of their ability to yield optically active epoxy compound quite effectively. Reference may be made to Jacobsen, E. N., Zhang, W., PCX Int. Appl. WO. 9114, 694. US, Appl. 496,992, 1990, pp 63, wherein the author described condensation of 3-ferr-butyl salicylaldehyde with R,R 1,2 diphenyl 1,2 ethane diamine to yield Schiff base which on complexation with manganese(III) metal ion give a complex which was used as catalyst for the epoxidation of cis p-methyl styrene using two phase system containing Na2B4O7.10 H2O Clorox- sodium hydroxide as oxidant in dichloromethane and water with 70 % yield and 85 % enantiomeric excess. The drawbacks of the system are, (i) yields and selectivity are still not up to the desired level of more than 98%. Katsuki, T. in Japanese patent application laid- open No. 301878, (1993) described further modification in the catalyst reported by Jacobsen E. N. et al. as described in the previous paragraph by altering substituent tert-butyl group by more bulkier groups like substituted alkylphenyls and also the ethylenediamine collar by preparing non commercial diamines with a significant increase in chemical and optical yields. However, the core of the catalyst remains manganese(III) SALEN. Thus substituted salicylaldehydes (prepared in more than 6 steps) and diamines (prepared in more than 13 steps) are condensed to yield desired Schiff bases that were subsequently reacted with Mn salt to yield the catalysts. These complexes were used as catalysts in the epoxidation of non-functionalised olefins using iodosylbenzene, 2-iodosylbenzoicacid hydrogen peroxide and sodium hypochlorite. A range of non-functionalized olefins gave epoxide yield 52-82% and enantiomeric excess 79-94% with iodosylbenzene as oxidant in 24 hours while with sodium hypochlorite as oxidant epoxide yield ranges between 45-72% and enantiomeric excess 55-95%. The drawbacks of this system are, (i) catalyst synthesis involves multi-step processes (ii) reaction time is too long (-24 hrs), (iii) utilizes expensive oxidant (iodosyl benzene) in order to give reasonable yields (52-82%) and enantiomeric excess above 79% with various olefins. Bell, D., Miller, D., Attrill, R.P., PCT Int. Appl. WO 94, 03, 271(1994) / GB Appl. 1992/16,662,06 (1992) described synthesis of several substituted SALEN Schiff base complexes of transition metal and their utilization in enantioselective epoxidation of 2,2-dimethyl 6-pentaflouro ethyl 2H-1-benzopyran using aqueous sodium hypochlorite, di-sodium hydrogen phosphate (pH-11) in dichloromethane. The only change in the catalysts described here was 2,3-diaminotetrahydrofuran and 3,4-diaminotetrahydrofuran was used in place of commercially available chiral diamines. A multi step synthesis of these amines is described. Moreover the catalysis part described the use of unresolved catalyst with no mention of chiral induction. Here again as in the preceding patent the drawbacks are, (i) synthesis of the diamine used is multi step and unresolved therefore, of little commercial value. Katsuki, T, et al., in preparation of optically active epoxides using chiral manganese binaphthyl catalysts. U.S. (1997), 18 pp Cont.-in-part of US patent No. 5,420,314/(1995), and also in Japanese Patent appl. 94/25,337,23, (1996) described a detailed multi step synthesis of substituted silyl and naphthyl manganese(III) Schiff base complexes for producing epoxy compounds claiming the epoxidation of indene (chemical yield 53%), asymmetric yield (92%) with Iodosyl benzene as oxidant in 24 hours. They also epoxidised benzopyran with the same oxidant and achieved 70% chemical yield, 94% asymmetric yield. Expensive oxidants such as 2-Iodosyl benzoic acid and penta fluoro iodosyl benzene are also described. However, this strategy has got the following drawbacks; (i) Some of these catalysts show high activity and selectivity but they require expensive oxidants such as iodosyl benzene, 2-Iodosyl benzoic acid, penta fluoro iodosyl benzene etc (ii) most of these epoxidation reactions utilizing earlier mentioned complexes as catalyst require 16-24 hours for obtaining the maximum conversions with higher selectivity under the reported reaction conditions. Jacobsen E. N. et al., in United States Patent No. 5,637,739 (1997) described the synthesis of complexes having salen derivatives as ligand with manganese (III) metal ion and their use as catalyst for the chiral epoxidation of non-functionalised olefins. Using these catalyst (0.5-2.0 mol%) the epoxide conversions (-94-97%) and enantiomeric excesses (51-96%) for chromenes within 12 hours is reported, while the use of 20mol% of 4-phenyl pyridine N-oxide/4-t-butylpyridine-N-oxide as axial base/co-oxidant with these catalysts reduced the time period to 1-5 hours. Plain chromene failed to give any epoxide. The main drawbacks of the system are, (i) in order to show high activity and selectivity these catalysts required high quantities (20mol %) of expensive 4-phenyl pyridine N-oxide/4-t-butylpyridine-N-oxide as axial base/co-oxidant, (ii) turn over numbers of-50 are not very high (iii) System do not yield epoxide with plain chromene. In our earlier patent Kureshy, R. I. et al. 1352/DEL/99 and 1353/DEL/99, we have reported manganese(III) Schiff base complexes having inbuilt phase transfer capability (five steps synthesis of the catalyst is described) and achieved enantioselective epoxidation of indene (Chemical yield >99% , asymmetric yield 81%) , 6-Cyano chromene (Chemical yield >99, asymmetric yield 100%) and styrene (Chemical yield >99% ,asymmetric yield 36-54%) within the period of 1-10 hours in presence of inexpensive simple pyridine N-oxidc/dioxane (lOmol %) as cooxidant/ axial base and sodium hypochlorite as oxidant. In the post epoxidation work-up process chromatographic separation is required to separate product epoxide from the catalyst. The main drawback of this system is (i) at least five step synthesis is required in order to create inbuilt phase transfer capability in the catalyst (ii) takes 1-10 hours for completion of epoxidation reaction (iii) post epoxidation work-up protocol is typical of homogeneous catalytic system and require chromatographic separation of the catalyst and the product epoxide. The main object of the present invention is to provide a process for the preparation of novel chiral SALEN transition metal catalyst useful in enantioselective epoxidation of prochiral olefins which obviates the drawbacks as detailed above. Another object of the present invention is to provide a process for the synthesis of optically active transition metal complexes of the formula 1 where RpRg independently represent hydrogen atom, alkyls such as methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, alkoxys such as methoxy, ethoxy, halogens such as fluro, chloro, bromo, trifluromethyl, X may be none, methylene, alkyl substituted methylenes Where in alkyls such as methyl, ethyl, propyl, iso- propyl, n-butyl, A-B-A may be chirally pure vicinal diamines such S, S (+) 1, 2 diamino cyclohexane, R, R (-) 1, 2 diamino cyclohexane, S, S (-) 1, 2, diphenyl diamino ethane, R, R (+) 1,2 diphenyl diamino ethane, S (+) 1,2 diaminopropane, R (-) 1,2 diaminopropane and (m) may be 3-5 repetitive units and M can be transition metal ion such Cobalt(II), Manganese(III), Ruthenium (III), Nickel(II), Copper(II), Chromium(III), Osmium(III) and Y represents anion like chloride, bromide, iodide, perchlorate, phosphorous hexaflouride and Z = oxygen or nitrogen, n = 0-1. Still another object of the present invention is to provide the catalytic activity of the modified crural complexes to show epoxide conversion >99% and enable enantioselectivity in the range of 36 to 100%. Yet another object of the present invention is to have a simple and cost effective synthesis of the modified chiral SALEN metal complexes devoid of many complicated steps. Accordingly the present invention provides a process for the preparation of novel chiral SALEN transition metal catalyst of formula 1 useful in enantioselective epoxidation of prochiral olefins (Formula Removed) Formula (1) wherein R1-R8 independently represent hydrogen atom, alkyls such as methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, alkoxys such as methoxy, ethoxy, halogens such as fluoro, chloro, bromo, triflouromethyl, X may be none, methylene, alkyl substituted methylenes where in alkyls such as methyl, ethyl, propyl, iso- propyl, n-butyl, A-B-A is chirally pure vicinal diamines such as S, S (+) 1,2 diamino cyclohexane, R, R (-) 1,2 diamino cyclohexane, S, S (-) 1,2, diphenyl diamino ethane, R, R (+) 1,2, diphenyl diamino ethane, S (+) 1,2 diaminopropane, R (-) 1,2 diaminopropane and (m) may be 3-5 repetitive units and M is transition metal ion selected from Cobalt(II), Manganese (III), Ruthenium (III), Nickel(II), Copper(II), Chromium(III), Osmium(III) and Y represents anion selected from chloride, bromide, iodide, perchlorate, phosphorous hexaflouride and Z = oxygen or nitrogen, n = 0-1, the said process comprises: (i) coupling of substituted salicylaldehyde with aliphatic aldehyde or ketone in presence of acid by conventional methods to give polymerizable substituted bis-salicylaldehyde then reacting with a chiral diamine using conventional condensation reaction to obtain chiral Schiff base ligand; (ii) refluxing the said Schiff base ligand with transition metal salt in an organic solvent such as herein described till completion of reaction under inert atmosphere; (iii) allowing the reaction mixture to cool at room temperature under aerobic conditions; (iv) adding a source of anion and recovering chiral SALEN catalyst so formed by known precipitation method. In an embodiment of the present invention the substituted aldehydes used may be selected from 3-alkyl salicylaldehyde such 3-methyl salicylaldehyde, 3-ethyl salicylaldehyde, 3-n-propyl salicylaldehyde, 3-iso-propyl salicylaldehyde, 3-n-butyl salicylaldehyde, 3-iso-butyl salicylaldehyde, 3-tert-buty\ salicylaldehyde, halo salicylaldehyde such as 3-flouro salicylaldehyde, 3-chloro salicylaldehyde, 3-bromo salicylaldehyde, 3-iodo salicylaldehyde, 3-triflouromethyl salicylaldehyde, alkoxy salicylaldehyde such as 3-methoxy salicylaldehyde, 3-ethoxy salicylaldehyde and nitrogen containing such as 3-nitro salicylaldehyde. In another embodiment of the present invention the coupling reaction may be selected from a temperature in the range 50-150° C. In yet another embodiment of the present invention the aldehyde/ketone used may be selected from formaldehyde, paraformaldehyde, trioxane, acetone, 2-butanone, 2-pentanone, 3-pentanone, or mixture thereof. In still another embodiment of the present invention the acid used may be selected from acetic acid, hydrochloric acid, hydrofluoric acid and sulfuric acid and mixture thereof. In another embodiment of the present invention the transition metal salt used may be selected from manganese, cobalt, nickel, iron, chromium, ruthenium, osmium, copper. Yet another embodiment of the present invention the organic solvent used may be selected from alcoholic solvent such as methanol, ethanol, propanol, butanol, halo solvents such as dichloromethane, 1,2 dichloroethane, chloroform or a mixture there of. In still another embodiment of the present invention the post reflux cooling in presence of air may be augmented by bubbling/and or exposed to oxygen, air and the mixture there of. In another embodiment of the present invention, the counter ion used may be selected from alkali metal halide such as lithium chloride, sodium chloride, potassium chloride, lithium bromide, sodium bromide, potassium bromide, lithium iodide, sodium iodide, potassium iodide or alkali metal perchlorate such as lithium perchlorate, sodium perchlorate, potassium perchlorate or alkali metal hexaflourophosphate such as potassium hexaflourophosphate. In the process of the present invention, the syntheses of modified chiral Schiff base derived from specially designed polymerisable salicylaldehyde was carried out using appropriate commercially available phenols by first introducing aldehyde group followed by coupling reaction in presence of aldehyde such as formaldehyde, paraformaldehyde, trioxane or mixture thereof in presence of hydrochloric acid, acetic acid and sulfuric acid to give the desired polymerisable substituted salicylaldehyde which was then interacted with appropriate commercially available chiral diamines in a solvent such as ethanol and methanol, nitriles such as acetonitrile and propionitrile, halogenated hydrocarbon such as dichloromethane, chloroform and 1,2 dichloroethane most preferably ethanol to give rise the modified chiral Schiff bases which are recrystallized with appropriate solvents and characterized by elemental analysis, IR, H NMR spectroscopy before these are used for the synthesis of the metal complexes which are prepared by thus synthesised chiral Schiff base compounds by dissolving or suspending one of these in an alcoholic solvent such as methanol, ethanol, a nitrile solvent such as acetonitrile, propionitrile or a halogenated hydrocarbon such as dichloromethane, chloroform and 1,2 dichloroethane most preferably ethanol and methanol and mixture thereof followed by addition of metal salt in an amount of 0.5-10 molar equivalent preferably 1-3 molar equivalent initially under inert atmosphere finally under aerobic condition to yield desired optically active complex although if required acetate ion may be replaced by chloride, hexaflourophosphate to give the complexes used as catalysts for the epoxidation of non-mnctionalised prochiral alkenes with several terminal oxidants such as sodium hypochlorite, hydrogen peroxide, alkyl hydroperoxide, molecular oxygen (with sacrificial reductant), per benzoic acid, such as m-chloro per benzoic acid aryl iodosyl benzene, oxone more preferably sodium hypochlorite, hydrogen peroxide , oxone, tetrabutyl ammonium hydroxide, m-chloro per benzole acid and cheaper cooxidant/ axial base/ additive such as substituted and non substituted pyridine N-oxide, cyclic ethers such as 1,4 dioxane, furan, pyrans, dimethyl sulphoxide, inorganic salts of carboxylic acid such sodium acetate, ammonium acetate, sodium benzoate and sodium bicarbonate, imidazole, substituted imidazole most preferably pyridine N-oxide and an alkylated substituted and unsubstituted alkyl imidazoles in solvents like halohydrocarbon preferably dichloromethane, 1,2 dichloroethane or alkyl nitrile preferably acetonitrile, propionitrile, alcoholic solvent more preferably dichloro methane or the mixture of methanol and dichloromethane which showed catalytic activity for epoxide conversion >99% and enable enantioselectivity in non functionalised olefins such as styrene, chromene and indene in the range of 36 - 100% in a relatively shorter period of time in 1 to 6 hours for non-functionalized olefins. The activity of the catalyst in a metal base catalysed system is largely dependent on the availability of the active sites to the reactants. The chemo and enantio selectivity of the system depends on mode of approach of the substrate, which is largely governed by shape, size and polarity of the substituents on the ligand system of the complex. The inventive steps involved in the present invention are i) the number of the active sites were increased by making polymeric complexes in order to achieve high catalytic activity; ii) simple synthetic procedures are used in the present invention to synthesise desired high molecular weight catalysts in three steps starting from the preferred salicylaldehyde; iii) high molecular weight of catalysts enabled the work up protocol simpler as catalyst-product separation after completion of catalytic epoxidation reaction can be achieved by precipitation method using commonly used non-polar solvents; iv) the time period of the epoxidation reaction was reduced to 1-6 hours from the previously reported 1-10 hours, v) high conversion (>99%) and enantiomeric excess's (ee's) (35->99%) were achieved with cheaper oxidant like sodium hypochlorite. vi) cheaper axial base like pyridine N-oxide was employed in lower molar ratios (5 equivalent with respect to the catalyst). The following examples are given by way of illustration of the present invention and therefore should not be construed to limit the scope of the present invention. In a typical synthesis of the preferred optically active transition metal complexes as catalysts are described in following examples, in general appropriate substituted polymerizable salicylaldehydes are prepared by using simple synthetic procedures. These polymerizable salicylaldehydes are interacted with appropriate chiral diamines to form novel improved catalyst precursor chiral Schiff bases. The characterization of these ligands is accomplished by elemental analysis, IR and H NMR spectroscopy. These polymerizable Schiff base ligands were interacted with appropriate metal ion to get desired metal complexes used as chiral epoxidation catalyst. EXAMPLE 1 Preparation of poly [(R,R )- N, N - bis {3-( 1,1-dimethyl ethyl) - 5 - methylene-salicylidine}l,2 - diphenyl-1,2 ethane diaminato (2-) manganese(III)] chloride (RRPTBSALDPMN) Step I: Synthesis of 5, 5 methylene-di-3-tertiary butyl salicylaldehyde 3-tert-buty\ salicylaldehyde (21.36 g) was treated with paraformaldehyde (l.8Og) in 16 ml glacial acetic acid and 2 ml sulfuric acid under nitrogen atmosphere. The resulting solution was allowed to heat up to 90° C with stirring for 24 hrs. The reaction mixture was poured into the cold water and allowed to stand overnight. The deposited dark brown solid was extracted with petroleum ether (3x 15 ml). The organic layer was dried over sodium sulfate. The dark brown compound was purified by silica gel column chromatography using hexane-ethyl acetate as eluent to yield light colored compound, yield 30.9 g, (70 %), m. p. 99-100°C, 1H NMR (CDC13, 200MHz)δ ppm 11.72(s, 2H, OH) 9.82(s, 2H, HCO), 7.37 (d, 2H, aromatic Jm==2.14), 7.14(d, 2H, aromatic, Jm =2.14), 3.93(s, 2H, methylene) 1.40(s, 9H, methyl). STEP II: Poly [(R,R)-N,N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1,2-ethylene diamine] The product from step I (7.36 g) and 1R,2R (-) 1,2 diphenyl ethylene diamine (4.24 g) were taken in absolute ethancl (40 ml) and refluxed for 2.5 hours yielding yellow colored oligomeric compound. It was filtered and washed with ethanol and dried in vacuum, Yield 8.84 g, 85%, m. p, 220°C. Elemental analysis, single unit C37H40N2O2. IR (KBr), (H-C=N) 1630 cm-1, 1H NMR (CDC13, 200MHz) δ ppm 13.56 (bs, 2H, OH), 8.22 (s, 2H, azomethine), 7.13 (bs, 10H, phenyl), 7.03 (d, 2H, aromatic), 6.67(d, 2H, aromatic), 4.64(s,2H, methylene), 3.66 (s, 2H, asymmetric), 1.34(s, 18H, t-butyl). STEP III: The product from step II (4.87 g) was taken in 40 ml of dichloromethane and was interacted with ethanolic solution of (4.41 g) Manganese acetate under reflux condition in an inert atmosphere for 6 hours. After completion of reaction, the reaction mixture was cooled to room temperature, lithium chloride (1.13 g) was added and the mixture was allowed to stir for 5 hours, while bubbling air and filtered. The solvent was completely evaporated from the filtrate and the residue was extracted with dichloromethane (50 ml). The organic layer was washed with water, brine and dried over sodium sulfate. After partial removal of dichloromethane the desired complex (1) was precipitated by the addition of petroleum ether (40:60) and dried under vacuum. Yield, 5.27 g: 90%, elemental analysis, C37H40 ClN2O3Mn, IR (KBr) v(H-ON) 1590. EXAMPLE 2 Preparation of poly [(S,S)-N, N -bis {3-(l,l-dimethylethyl)-5-methylene-salicylidine}l, 2 - diphenyl-1,2 ethane diaminato (2-) manganese (III) chloride] (SSPTBSALDPMN) STEP I: Poly [(S,S)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1, 2-ethylene diamine] 5, 5 methylene-di-3-tertiary butyl salicylaldehyde (7.36 g) and 1S.2S (-) 1,2-diphenylethylene diamine (4.24 g) were taken in absolute ethanol (40 ml) and refluxed for 2-3 hours yielding yellow colored oligomeric Schiff base. It was filtered and washed with ethanol and dried in vacuum. Yield 8.84g, 85%, m.p. 220°C, elemental analysis, C37H40N2O2. 'H NMR (CDC13, 200MHz) δ ppm 13.56 (bs, 2H, OH), 8.22 (s, 2H, azomethine), 7.13 (bs, 10H, phenyl), 7.03 (d, 2H, aromatic), 6.67(d, 2H, aromatic), 4.64(s, 2H, methylene), 3.66 (s, 2H, asymmetric), 1.34(s, 18H, t-butyl). STEP II: The product from step I of example 2 (4.87 g) in 40 ml dichloromethane was refluxed with (4.4 Ig) Manganese acetate in ethanol under inert atmosphere for 6 hours. After completion of reaction the reaction mixture was cooled to room temperature and lithium chloride (1.13 g) was added and the mixture was allowed to stir for 5 hours, while exposed to air and filtered. The solvent was completely evaporated from the filtrate and the residue was extracted with dichloromethane (50 ml). The organic layer was washed with water, brine and dried over sodium sulfate. After partial removal of dichloromethane the desired complex (2) was precipitated by the addition of petroleum ether (40:60) and dried under vacuum. Yield, 5.27 g: 90%, elemental analysis, C37H40 ClN2O3Mn, IR (KBr) v(H-ON) 1590. EXAMPLE 3 Preparation of poly [(S,S)-N,N'-bis{3-(l,l-dimethylethyl)-5-methylene salicylidine} cyclohexene-l,2-diaminato (2-) manganese(III) chloride] (SSPTBSALHEXMN) STEP I: 5, 5 methylene-di-3-tertiary butyl salicylaldehyde (6.62 g) and 1S,2S (+) 1,2-diaminocyclohexane (2.05 g) were taken in absolute ethanol (50 ml) and refluxed for 2 hours to obtain oligomeric [(S,S)-N,N'-bis-{3-(l,l-dimethylethyl)-5-methylene salicylidine} cyclohexene 1,2 -diamine]. It was filtered and washed with ethanol and dried in vacuum. Yield, 6.82 g (85%), m. p., 218°C, elemental analysis, C29H38N2O2. 1H NMR (CDC13, 200 MHz) δ ppm 13.77 (bs, 2H, OH), 8.21 (s, 2H, azomethine), 6.74 (d, 2H, aromatic, Jm =2Hz), 7.05(d, 2H, aromatic, Jm =2Hz), 3.68 (s, 2H, methylene), 3.29(bm, 2H, asymmetric) 1.87 (m, 8H, cyclohexane), 1.36(s, 8H, t- butyl). STEP II: The product from step I (3.99 g) in ethanol was allowed to react with Manganese acetate (4.41 g) under reflux condition in an inert atmosphere for 6 hours. After completion of reaction, the reaction mixture was cooled to room temperature, lithium chloride (1.13 g) was added and the mixture was allowed to stir for another 5 hours, while bubbling oxygen and filtered. The solvent was removed from the filtrate and the residue was extracted with dichloromethane (50 ml). The organic layer was washed with water, brine and dried over sodium sulfate. After partial removal of dichloromethane the desired complex (1) was precipitated by the addition of petroleum ether (40:60) and dried under vacuum. Yield, 4.55 g: 92 %, elemental analysis, C29H38 ClN2O3Mn, IR (KBr) v(H-C=N) 1590. EXAMPLE 4 Preparation of poly [(.R,R)-N,N'-bis{3-(1,1-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) manganese(III) chloride] (RRTBSALHEXMN) STEP I: 5, 5 methylene-di-3-tertiary butyl salicylaldehyde (6.62 g) and JR,2R (+) 1,2-diaminocyclohexane (2.05 g) were taken in absolute ethanol (50 ml) and refluxed for 2.5 hours to obtain yellow colored oligomeric compound poly {(R,R)-N,N' bis {3(1,1-dimethyl ethyl)-5-methylene salicylidine} cyclohexenel,2 diamine}. It was filtered and washed with ethanol and dried in vacuum, Yield, 6.88 g (84 %), m. p, 218°C, elemental analysis, C29H38N2O2. 1H NMR (CDC13, 200 MHz) δ ppm 13.77 (bs, 2H, OH), 8.21 (s, 2H, azomethine), 6.74 (d, 2H, aromatic, Jm =2Hz), 7.05(d, 2H, aromatic, Jm =2Hz), 3.68 (s, 2H, methylene), 3.29(bm, 2H, asymmetric) 1.87 (m, 8H, cyclohexane), 1.36(s, 8H, t- butyl). STEP II: The product from step I (3.99 g) of the example 4 in ethanol was allowed to react with Manganese acetate (4.41 g) under reflux condition in an inert atmosphere for 6 hours. After completion of reaction, the reaction mixture was cooled to room temperature, lithium chloride (1.13 g) was added and the mixture was further stirred for 5 hours, while exposed to air and filtered. The solvent was removed from the filtrate and the residue was extracted with dichloromethane (50 ml). The organic layer was washed with water, brine and dried over sodium sulfate. After partial removal of dichloromethane the desired complex (1) was precipitated by the addition of petroleum ether (40:60) and dried under vacuum. Yield, 4.45 g: 90%, elemental analysis, C29H38ClN2O3Mn, IR (KBr) v(H-C=N) 1590. EXAMPLE-5 Preparation of poly [(R,R)-N,N'-bis{3-(l,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) manganese(III) hexafluorophosphate] (RRTBSALHEXMN) STEP I: 5, 5 methylene-di-3-tertiary butyl salicylaldehyde (6.62 g) and 1R,2R (+) 1,2-diaminocyclohexane (2.05 g) were taken in absolute ethanol (50 ml) and refluxed for 2.5 hours to obtain yellow colored oligomeric compound poly \|(R,R)-N,N' bis (3(1,1-dimethyl ethyl)-5-methylene salicylidine} cyclohexenel,2 diamine}. It was filtered and washed with ethanol and dried in vacuum, Yield, 6.88 g (84 %), m. p, 218°C, elemental analysis, C29H38N2O2. 'H NMR (CDC13, 200 MHz) δ ppm 13.77 (bs, 2H, OH), 8.21 (s, 2H, azomethine), 6.74 (d, 2H, aromatic, Jm =2Hz), 7.05(d, 2H, aromatic, Jm =2Hz), 3.68 (s, 2H, methylene), 3.29(bm, 2H, asymmetric) 1.87 (m, 8H, cyclohexane), 1.36(s, 8H, t-butyl). STEP II: The product from step I (3.99 g) of the example 4 in ethanol was allowed to react with manganese acetate (4.41 g) under reflux condition in an inert atmosphere for 6 hours. After completion of reaction, the reaction mixture was cooled to room temperature, lithium chloride (1.13 g) was added and the mixture was further stirred for 5 hours, while exposed to air and filtered. The solvent was removed from the filtrate and the residue was extracted with dichloromethane (50 ml). The organic layer was washed with water, brine, dried over sodium sulfate and filtered. The filtrate was stirred with potassium hexaflourophosphate (2.48 g) for 6 hours and after partial removal of dichloromethane the desired complex (1) was precipitated by the addition of petroleum ether (40:60) and dried under vacuum. Yield, 4.56 g: 90%, elemental analysis, C29H38F6lN2O3PMn, IR (KBr) v(H-C=N) 1590. EXAMPLE- 6 Synthesis of 5, 5-(l', 1' dimethyl methylene)- di-3-tertiary butyl salicylaldehyde. 3-tertiary butyl salicylaldehyde (21.36g) was treated with acetone (6.95g) in 10 ml of 1:1 mixture of concentrated hydrochloric and sulphuric acid under argon atmosphere. The resulting solution was allowed to heat up to 55 C with stirring for two days. The reaction mixture was poured into crushed ice (200g) and allowed to stand over night. The deposited dark colored sticky material was extracted with petroleum ether (3x 20ml). The organic layer was chromatographed using hexane-ethyl acetate as eluent to yield the off white compound, yield 5.92g (25%). Elemental analysis C25H31O4. EXAMPLE-7 Synthesis of 5, 5 methylene-di-3-chloro salicylaldehyde 3-chloro salicylaldehyde (15.7 g) was treated with paraformaldehyde (1.5 g) in 16 ml glacial acetic acid and 2 ml sulfuric acid under nitrogen atmosphere. The resulting solution was allowed to heat up to 90° C with stirring for 24 hrs. The reaction mixture was poured into the cold water and al'owed to stand overnight. The deposited dark brown solid was extracted with hexane (3x 15 ml). The organic layer was dried over sodium sulfate. The dark gray compound was purified by silica gel column chromatography using hexane-ethyl acetate as eluent to yield light colored compound. Yield 9.8 g, (60 %). Elemental analysis C15H10Cl2O4. EXAMPLE-8 Synthesis of 5, 5 methylene-di-3-methoxy salicylaldehyde 3-methoxy salicylaldehyde (15.0 g) was treated with paraformaldehyde (1.5 g) in 16 ml glacial acetic acid and 2 ml sulmric acid under nitrogen atmosphere. The resulting solution was allowed to heat up to 90° C with stirring for 24 hrs. The reaction mixture was poured into the cold water and allowed to stand overnight. The deposited dark brown solid was extracted with chloroform (3x 15 ml). The organic layer was dried over sodium sulfate. The dark brown compound was purified by silica gel column chromatography using hexane-dichloromethane as eluent to yield light colored compound. Yield, 6.3 g, (40%). Elemental analysis, C17H16O6. EXAMPLE-9 Synthesis of 5, 5 methylene-di-3-nitro-salicylaldehyde 3-nitro salicylaldehyde (16.7 g) was treated with paraformaldehyde (1.5 g) in 16 ml glacial acetic acid and 2 ml sulfuric acid under nitrogen atmosphere. The resulting solution was allowed to heat up to 90° C with stirring for 24 hrs. The reaction mixture was poured into the cold water and allowed to stand overnight. The deposited dark brown solid was extracted with dichloromethane (3x 15 ml). The organic layer was dried over sodium sulfate. The dark brown compound was purified by silica gel column chromatography using hexane-dichloromethane as eluent to yield yellow colored compound, yield 10.3 g, (60 %),. Elemental analysis, C15H10N2O8 EXAMPLE 10 Preparation of poly [(R,R)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene-salicylidine}l,2 - diphenyl-1,2 ethane diaminato (2-) cobalt (II)] Poly [R,R)-N,N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1,2- ethylene diamine] (0.544 g) and sodium acetate (0.164 g) was allowed to reflux in ethanol (25 ml) under inert atmosphere. To this refluxing solution hot and degassed solution of cobalt (II) acetate (0.249 g) in water (10 ml) was added and the mixture was allowed to reflux for 1.5 hours. A brick red precipitate of the desired complex was filtered and washed ethanol. Yield, 3.43 g (95 %), elemental analysis C37H38N2O2Co IR (KBr) v(H-C=N) 1590. EXAMPLE 11 Poly [(S,S)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene-salicylidine}l,2 - diphenyl-1,2 ethane diaminato (2-) cobalt(II)] Poly [(S,S)-N,N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1,2- ethylene diamine] (0.544 g) and sodium acetate (0.164 g) was allowed to reflux in ethanol (25 ml) under inert atmosphere. To this refluxing solution hot and degassed solution of cobalt (II) acetate (0.249 g) in water (10 ml) was added and the mixture was allowed to reflux for 1.5 hours. A brick red precipitate of the desired complex was filtered and washed ethanol. Yield, 3.30 g (91 %), elemental analysis C37H38N2O2Co, IR (KBr) v(H-C=N) 1590. EXAMPLE 12 Preparation of poly [(S,S)-N,N'-bis{3(l,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) cobalt(II)] Poly [(S,S)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1, 2- ethylene diamine] (0.446 g) and sodium acetate (0.164 g) was allowed to reflux in ethanol (25 ml) under inert atmosphere. To this refluxing solution hot and degassed solution of cobalt (II) acetate (0.249 g) in water (10 ml) was added and the mixture was allowed to reflux for 2 hours. A brick red precipitate of the desired complex was filtered and washed ethanol. Yield, 2.82 g (93 %),elemental analysis C29H36N2O2Co, IR (KBr) v(H-ON) 1590. EXAMPLE 13 Preparation of poly [(R,R)-N,N'-bis{3(l,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) cobalt(II)] Poly [(R,R)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1, 2- ethylene diamine] (0.446 g) and sodium acetate (0.164 g) was allowed to reflux in ethanol (25 ml) under inert atmosphere. To this refluxing solution hot and degassed solution of cobalt (II) acetate (0.249 g) in water (10 ml) was added and the mixture was allowed to reflux for 2 hours. A brick red precipitate of the desired complex was filtered and washed ethanol. Yield, 2.76 g (91%), elemental analysis C29H36N2O2Co, IR (KBr) v(H-C=N) 1590. EXAMPLE 14 Preparation of poly [(R,R)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene-salicylidine}l,2 - diphenyl-1,2 ethane diaminato (2-) nickel (II)] Poly [(R,R)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1, 2- ethylene diamine] (0.544 g) was taken in 1:1 mixture of methanol and dichloromethane (20 ml) and was added to a solution of nickel acetate (0.249g in 20 ml dichloromethane). To this mixture triethylamine (0.89 ml) was added and the resulting solution was refluxed for 6 hours. After completion of reaction the solvent was removed. The residue was dissolved in dichloromethane, washed with water and brine and dried over sodium sulphate. Removal of solvent yielded the desired complex. Yield, 3.32 g (92%), elemental analysis C37H38N2O7Ni, IR (KBr) v(H-C=N) 1590. .EXAMPLE 15 Poly [(S,S)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene-salicylidine}l,2 - diphenyl-1,2 ethane diaminato (2-) nickel(II)] Poly [(S,S)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1, 2- ethylene diamine] (0.544 g) was taken in 1:1 mixture of methanol and dichloromethane (20 ml) and was added to a solution of nickel acetate (0.249g in 20 ml dichloromethane). To this mixture triethylamine (0.89 ml) was added and the resulting solution was refluxed for 6 hours. After completion of reaction the solvent was removed. The residue was dissolved in dichloromethane, washed with water and brine and dried over sodium sulphate. Removal of solvent yielded the desired complex. Yield, 3.44 g (95%), elemental analysis C37H38N2O2Ni, IR (KBr) v(H-C=N) 1590. EXAMPLE 16 Preparation of poly [(S,S)-N,N'-bis{3(l,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) nickel(II)] Poly [(S,S)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1, 2- ethylene diamine] (0.446 g) was taken in 1:1 mixture of methanol and dichloromethane (20 ml) and was added to a solution of nickel acetate (0.249g in 20 ml dichloromethane). To this mixture triethylamine (0.89 ml) was added and the resulting solution was refluxed for 6 hours. After completion of reaction the solvent was removed. The residue was dissolved in dichloromethane, washed with water and brine and dried over sodium sulphate. Removal of solvent yielded the desired complex. Yield, 2.76 g, (91%), elemental analysis C29H36N2O2 Ni, IR (KBr) v(H-C=N) 1590. EXAMPLE 17 Preparation of poly [(R,R)-N,N'-bis{3(l,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) nickel (II)] Poly [(R,R)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1, 2- ethylene diamine] (0.446 g) was taken in 1:1 mixture of methanol and dichloromethane (20 ml) and was added to a solution of nickel acetate (0.249g in 20 ml dichloromethane). To this mixture triethylamine (0.89 ml) was added and the resulting solution was refluxed for 6 hours. After completion of reaction the solvent was removed. The residue was dissolved in dichloromethane, washed with water and brine and dried over sodium sulphate. Removal of solvent yielded the desired complex. Yield, 2.85 g, (94%), elemental analysis C2qH36N2O2Ni, IR (KBr) v(H-C=N) 1590. Following catalysts are also prepared by the same process as herein described. Preparation of poly [(S,S)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene-salicylidine}l,2 - diphenyl-1,2 ethane diaminato (2-) chromium (III) chloride] Yield, 3.45 g (91%), elemental analysis C37H38ClN2O2Cr, IR (KBr) v(H-C=N) 1590. Poly [R,R)-N,N'-bis {3-(l,l-dimethylethyl)-5-methylene-salicylidine}l,2 - diphenyl-1,2 ethane diaminato (2-) chromium(III) chloride] Yield, 3.55 g (94%), elemental analysis C37H3SClN2O2Cr, IR (KBr) v(H-C=N) 1590. Preparation of poly [(S,S)-N,N'-bis{3-(l,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) chromium (III) chloride] Yield, 2.94 g, (92%), elemental analysis C29H36C1N2O2 Cr, IR (KBr) v(H-C=N) 1590. Preparation of poly [(^,/?)-N,N'-bis{3-(l,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) chromium (III) chloride] Yield, 3.04 g, (95%), elemental analysis C2l)H36ClN2O2Cr, IR (KBr) v(H-C=N) 1590. Preparation of poly [S,S)-N,N'-bis {3-(l,l-dimethylethyl) -5- methylene salicylidine} 1,2 - diphenyl-1,2 ethane diaminato (2-) copper (II)] Yield, 3.35 g, (92%), elemental analysis C37H38N2O2Cu, IR (KBr) v(H-C=N) 1590. poly[ (R,R)-N, N'-bis {3-(l,l-dimethylethyl) -5- methylene-salicylidine}l,2 - diphenyl-1,2 ethane diaminato (2-) copper(II) Yield, 3.27 g, (90%), elemental analysis C37H38N2O2Cu, IR (KBr) v(H-C=N) 1590. Preparation of poly [(5,5)-N,N'-bis{3(l,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) copper(II)] Yield, 2.88 g, (94%), elemental analysis C29H36N2O2 Cu, IR (KBr) v(H-C=N) 1590. Preparation of poly [(R,R)-N,N'-bis{3(l,l-dimethylethyl) -5- methylene salicylidine}cyclohexene-l,2-diaminato (2-) copper (II)] Yield, 2.82 g, (92%), elemental analysis C29H36N2O2Cu, IR (KBr) v(H-ON) 1590. Preparation of Potassium poly [(,S,S,)-N,N'-bis {3-(l,l-dimethylethyl) -5- methylene- salicylidine} 1,2 - diphenyl-1,2 ethane diaminato (2-) ruthenium (III) dichloride] Yield, 4.30 g, (95 %), elemental analysis C37H38Cl2N2O2RuK , IR (KBr) v(H-C=N) 1590. Potassium Poly [(R,R)N,N'-bis {3-(l,l-dimethylethyl) -5- methylene-salicylidine}l,2 - diphenyl-1,2 ethane diaminato (2-) ruthenium (III) dichloride] Yield, 4.07 g, (90%), elemental analysis C37H38Cl2N2O2RuK , IR (KBr) v(H-ON) 1590. Preparation of Potassium poly [(S,S)-KN'-bis{3-(1,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) ruthenium (III) dichloride] Yield, 3.67 g, (93%), elemental analysis C29H38Cl2N2O2RuK, IR (KBr) v(H-C=N) 1590. Preparation of Potassium poly [(R,R) - N,N'-bis {3-(l,l-dimethylethyl) - 5 - methylene salicylidine}cyclohexene-l,2-diaminato (2-) ruthenium (III) dichloride] Yield, 3.55 g, (90%), elemental analysis C29H36Cl2N2O2RuK, IR (KBr) v(H-C=N) 1590. Preparation of Potassium poly [(S,S) - N,N'-bis \|3-(l,l-dimethylethyl) - 5 - memylene- salicylidine} 1, 2- diphenyl-1, 2 ethane diaminato (2-) Osmium (III) dichloride] Yield, 4.70 g, (93 %), elemental analysis C37H38Cl2N2O2OsK IR (KBr) v(H-C=N) 1590. Preparation of Potassium poly [(R,R)-N,N' -bis {3-(l,l-dimethylethyl) -5- methylene- salicylidine} 1,2- diphenyl-1,2 ethane diaminato (2-) Osmium (III) dichloride] Yield, 4.60 g, (91%), elemental analysis C37H38Cl2N2O2OsK Preparation of Potassium poly [(5,5)-N,N'-bis {3(l,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) Osmium (III) dichloride] Yield, 4.12 g,(92%), elemental analysis, C29H36Cl2N2O2Os K , IR (KBr) v(H-C=N) 1590. Preparation of Potassium poly [(R,R)-N,N'-bis {3-(l,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) Osmium (III) dichloride] Yield, 4.03 g, (93%), elemental analysis, C29H36Cl2N2O2Os K, IR (KBr) v(H-ON) 1590. The main advantages of the present invention are: 1. Synthesis of high molecular weight optically active transition complexes and their precursor ligands involve simple reaction procedures and conditions. 2. Commercial LR grade ingredients required no further purification. 3. Final work up protocol of the post catalytic run is simple and requires simply precipitation of the catalyst just by addition of a non-polar organic solvents. 4. In absence of any detectable amount of side products along with high conversions (on GC and NMR scale) the final work up protocol is further easy separation of the catalyst which is quite difficult in other homogeneous system. 5. Good isolated yields of epoxides are achievable with inexpensive oxidation reagents under mild reaction conditions. 6. Reaction rates are significantly faster than reported so far with these types of catalysts especially with the extent of selectivity disclosed here. 7. The phase transfer reagents alkyl ammonium halide can be used with biphasic catalytic runs to increase the rate of epoxidation with improved enantioselection in some cases. We Claim: 1. A process for the preparation of novel chiral SALEN transition metal catalyst of formula 1 useful in enantioselective epoxidation of prochiral olefins (Formula Removed) Formula (1) wherein R1-R8 independently represent hydrogen atom, alkyls such as methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, alkoxys such as methoxy, ethoxy, halogens such as fluoro, chloro, bromo, triflouromethyl, X may be none, methylene, alkyl substituted methylenes where in alkyls such as methyl, ethyl, propyl, iso- propyl, n-butyl, A-B-A is chirally pure vicinal diamines such as S, S (+) 1,2 diamino cyclohexane, R, R (-) 1,2 diamino cyclohexane, S, S (-) 1,2, diphenyl diamino ethane, R, R (+) 1,2, diphenyl diamino ethane, S (+) 1,2 diaminopropane, R (-) 1,2 diaminopropane and (m) may be 3-5 repetitive units and M is transition metal ion selected from Cobalt(II), Manganese (III), Ruthenium (III), Nickel(II), Copper(II), Chromium(III), Osmium(III) and Y represents anion selected from chloride, bromide, iodide, perchlorate, phosphorous hexaflouride and Z = oxygen or nitrogen, n = 0-1, the said process comprises: (i) coupling of substituted salicylaldehyde with aliphatic aldehyde or ketone in presence of acid by conventional methods to give polymerizable substituted bis-salicylaldehyde then reacting with a chiral diamine using conventional condensation reaction to obtain chiral Schiff base ligand; (ii) refluxing the said Schiff base ligand with transition metal salt in an organic solvent such as herein described till completion of reaction under inert atmosphere; (iii) allowing the reaction mixture to cool at room temperature under aerobic conditions; (iv) adding a source of anion and recovering chiral SALEN catalyst so formed by known precipitation method. 2. A process as claimed in claim 1 wherein substituted salicylaldehydes used selected from 3-alkyl salicylaldehyde such 3 -methyl salicylaldehyde, 3 -ethyl salicylaldehyde, 3-n-propyl salicylaldehyde, 3-iso-propyl salicylaldehyde, 3-n-butyl salicylaldehyde, 3-iso-butyl salicylaldehyde, 3-rert-butyl salicylaldehyde, halo salicylaldehyde selected from 3-flouro salicylaldehyde, 3-chloro salicylaldehyde, 3-bromo salicylaldehyde, 3-iodo salicylaldehyde, 3-triflouromethyl salicylaldehyde, alkoxy salicylaldehyde such as 3-methoxy salicylaldehyde, 3-ethoxy salicylaldehyde and nitrogen containing such as 3- 3. A process as claimed in claims 1 and 2 wherein the coupling reaction is at a temperature in the range 50-1 50 ° C preferably at 90-95 ° C. 4. A process as claimed in claims 1 to 3 wherein the aldehyde/ketone used is selected from formaldehyde, paraformaldehyde, trioxane, acetone, 2-butanone, 2-pentanone, 3- pentanone preferably paraformaldehyde. 5. A process as claimed in claims 1to 4 the acid used is selected from mineral acids selected from hydrochloric acid, sulphuric acid, carboxylic acid selected from acetic acid and mixture thereof preferably glacial acetic acid and sulfuric acid. 6. nitro salicylaldehyde preferably 3-tert-butyl salicylaldehyde.carried 7. A process as claimed in claims 1 to 5 wherein the transition metal salt used is selected from manganese, cobalt, nickel, chromium, ruthenium, osmium and copper. 8. A process as claimed in claims 1 to 6 wherein the organic solvent used is selected from alcoholic solvents such as methanol, ethanol, propanol, butanol, halo solvents selected from dichloromethane, 1,2 dichloethane, chloroform or a mixture thereof. 9. A process as claimed in claims 1 to 7 wherein reaction mixture is cooled by bubbling air or exposed to oxygen and mixture thereof. 10. A process as claimed in claims 1 to 8 wherein the source of anion is selected from alkali metal halide or alkali metal perchlorate or alkali metal hexaflourophosphate preferably chloride by adding lithium chloride. 10. A process for the preparation of novel chiral SALEN transition metal catalyst useful in enantioselective epoxidation of prochiral olefins substantially as herein described with reference to the examples of formula 1 in this specification.

Full Text

The present invention relates to a process for the preparation of novel chiral
SALEN transition metal catalyst useful in enantioselective epoxidation of prochiral olefins.
The chirally enriched epoxides are important intermediates in the synthesis of optically active medicines, including 6-cyano-2,2-dimethylbenzopyran, indene and styrene oxides also ecofriendly pest control agents and flavors.
Enantioselective catalytic epoxidation of non-functionalised alkenes has emerged as a powerful tool for the synthesis of chirally enriched epoxides required as intermediates for chiral building blocks in the preparation of complex optically pure bio-active compounds. Several chiral drugs, viz., Crixivan (an HIV protease inhibitor), Cromakalim (a highly potent antihypertensive), Tetramisol ((5) form is a powerful anthelmintic) and many more under trial and developmental stage utilize optically pure epoxides as the key intermediate as reviewed by N. Collins, G. N. Sheldrake, J. Crossby (Eds), Chirality in Industry; The Commercial Manufacture and Application of Optically active Compound, Wiley, New Yorl, 1995; R. E. Gawley and J. Aube Principles of Asymmetric Synthesis, Ed. by J. E. Baldwin, Pergamon publication Chapter 8 Oxidation pp. 325 ; E. N. Jacobsen, In catalytic asymmetric synthesis, Ed. by Ojima, I. VCH publication, 1993. pp. 59.
Among functionalised alkenes, Sharpless asymmetric epoxidation of allylic alcohols has emerged as one of the most widely applied reactions in asymmetric synthesis using titanium tartrate in presence of tert-butyl hydroperoxide as oxidant showing highest enantioselectivity. (R. A. Johnson and K. B. Sharpless, In catalytic asymmetric synthesis, Ed. by Ojima, I. VCH publication, 1993. pp. 103). This method requires pre-coordinating

functional group on the substrate, in absence of which the method is no more enantioselective. Since many drug and agrochemical intermediates require epoxides of non-functionalised alkenes, this method is of little use for this purpose.
Bolm, C., in Angew. Chem. Int. Ed. Eng. 1991, 30, 403 has reviewed the enantioselective epoxidation catalysis. Central idea of the research in this area has been to achieve high enantioselectivity in the epoxidation of alkenes bearing no functionality require for precoordination to the catalyst. Their selectivity is determined solely through non bonded interactions. Hence, transition metals catalysts emerged as the most preferred strategy to accomplish this task. These catalysts can utilize a range of oxidants namely, molecular oxygen, lodosyl arenes, sodium hypochlorite, hydrogen peroxide, mono persulphates and alkyl hydroperoxide. It is likely that these catalysts will be oxo transfer agents analogous to Cytochrome P-450 class of heme containing proteins. Groves' land mark discovery of iron (III) porphyrin complexes models was the first successful step towards synthetic model of Cytochrome P-450. Since then many fascinating and sophisticated porphyrins have been synthesized which include Basket handle, Twin Coronet porphyrins, Picnic Basket derivatives, Strapped porphyrins, D4 symmetric metalloporphyrins (Me Murry, T. J., Groves, J. T., Cytochrome P-450, Ortiz deMontellano, PR (Ed.) Polonium, New York 1986, Chapter 1). Although high turnover numbers have been observed (more than 3000) with maximum enantioselection up to 76 % enantiomeric excess (ee's) was obtained for cis-ß methyl styrene, the synthesis of these porphyrins is very complicated. It involves multi step synthesis and requires many anhydrous and inert reaction conditions. Not withstanding multi step, yields are very low hence, these routes are of little commercial value.

In the last decades non-porphyrin based processes have been developed for asymmetric epoxidation of non-functionalised alkenes that employ an optically active manganese complex as an asymmetric catalyst. These processes are attracting attention because of their ability to yield optically active epoxy compound quite effectively.
Reference may be made to Jacobsen, E. N., Zhang, W., PCX Int. Appl. WO. 9114, 694. US, Appl. 496,992, 1990, pp 63, wherein the author described condensation of 3-ferr-butyl salicylaldehyde with R,R 1,2 diphenyl 1,2 ethane diamine to yield Schiff base which on complexation with manganese(III) metal ion give a complex which was used as catalyst for the epoxidation of cis p-methyl styrene using two phase system containing Na2B4O7.10 H2O Clorox- sodium hydroxide as oxidant in dichloromethane and water with 70 % yield and 85 % enantiomeric excess. The drawbacks of the system are, (i) yields and selectivity are still not up to the desired level of more than 98%.
Katsuki, T. in Japanese patent application laid- open No. 301878, (1993) described further modification in the catalyst reported by Jacobsen E. N. et al. as described in the previous paragraph by altering substituent tert-butyl group by more bulkier groups like substituted alkylphenyls and also the ethylenediamine collar by preparing non commercial diamines with a significant increase in chemical and optical yields. However, the core of the catalyst remains manganese(III) SALEN. Thus substituted salicylaldehydes (prepared in more than 6 steps) and diamines (prepared in more than 13 steps) are condensed to yield desired Schiff bases that were subsequently reacted with Mn salt to yield the catalysts. These complexes were used as catalysts in the epoxidation of non-functionalised olefins using iodosylbenzene, 2-iodosylbenzoicacid hydrogen peroxide and sodium hypochlorite. A range of non-functionalized olefins gave

epoxide yield 52-82% and enantiomeric excess 79-94% with iodosylbenzene as oxidant in 24 hours while with sodium hypochlorite as oxidant epoxide yield ranges between 45-72% and enantiomeric excess 55-95%. The drawbacks of this system are, (i) catalyst synthesis involves multi-step processes (ii) reaction time is too long (-24 hrs), (iii) utilizes expensive oxidant (iodosyl benzene) in order to give reasonable yields (52-82%) and enantiomeric excess above 79% with various olefins.
Bell, D., Miller, D., Attrill, R.P., PCT Int. Appl. WO 94, 03, 271(1994) / GB Appl. 1992/16,662,06 (1992) described synthesis of several substituted SALEN Schiff base complexes of transition metal and their utilization in enantioselective epoxidation of 2,2-dimethyl 6-pentaflouro ethyl 2H-1-benzopyran using aqueous sodium hypochlorite, di-sodium hydrogen phosphate (pH-11) in dichloromethane. The only change in the catalysts described here was 2,3-diaminotetrahydrofuran and 3,4-diaminotetrahydrofuran was used in place of commercially available chiral diamines. A multi step synthesis of these amines is described. Moreover the catalysis part described the use of unresolved catalyst with no mention of chiral induction. Here again as in the preceding patent the drawbacks are, (i) synthesis of the diamine used is multi step and unresolved therefore, of little commercial value.
Katsuki, T, et al., in preparation of optically active epoxides using chiral manganese binaphthyl catalysts. U.S. (1997), 18 pp Cont.-in-part of US patent No. 5,420,314/(1995), and also in Japanese Patent appl. 94/25,337,23, (1996) described a detailed multi step synthesis of substituted silyl and naphthyl manganese(III) Schiff base complexes for producing epoxy compounds claiming the epoxidation of indene (chemical yield 53%), asymmetric yield (92%) with Iodosyl benzene as oxidant in 24 hours. They

also epoxidised benzopyran with the same oxidant and achieved 70% chemical yield, 94% asymmetric yield. Expensive oxidants such as 2-Iodosyl benzoic acid and penta fluoro iodosyl benzene are also described. However, this strategy has got the following drawbacks; (i) Some of these catalysts show high activity and selectivity but they require expensive oxidants such as iodosyl benzene, 2-Iodosyl benzoic acid, penta fluoro iodosyl benzene etc (ii) most of these epoxidation reactions utilizing earlier mentioned complexes as catalyst require 16-24 hours for obtaining the maximum conversions with higher selectivity under the reported reaction conditions.
Jacobsen E. N. et al., in United States Patent No. 5,637,739 (1997) described the synthesis of complexes having salen derivatives as ligand with manganese (III) metal ion and their use as catalyst for the chiral epoxidation of non-functionalised olefins. Using these catalyst (0.5-2.0 mol%) the epoxide conversions (-94-97%) and enantiomeric excesses (51-96%) for chromenes within 12 hours is reported, while the use of 20mol% of 4-phenyl pyridine N-oxide/4-t-butylpyridine-N-oxide as axial base/co-oxidant with these catalysts reduced the time period to 1-5 hours. Plain chromene failed to give any epoxide. The main drawbacks of the system are, (i) in order to show high activity and selectivity these catalysts required high quantities (20mol %) of expensive 4-phenyl pyridine N-oxide/4-t-butylpyridine-N-oxide as axial base/co-oxidant, (ii) turn over numbers of-50 are not very high (iii) System do not yield epoxide with plain chromene.
In our earlier patent Kureshy, R. I. et al. 1352/DEL/99 and 1353/DEL/99, we have reported manganese(III) Schiff base complexes having inbuilt phase transfer capability (five steps synthesis of the catalyst is described) and achieved enantioselective epoxidation of indene (Chemical yield >99% , asymmetric yield 81%) , 6-Cyano

chromene (Chemical yield >99, asymmetric yield 100%) and styrene (Chemical yield >99% ,asymmetric yield 36-54%) within the period of 1-10 hours in presence of inexpensive simple pyridine N-oxidc/dioxane (lOmol %) as cooxidant/ axial base and sodium hypochlorite as oxidant. In the post epoxidation work-up process chromatographic separation is required to separate product epoxide from the catalyst. The main drawback of this system is (i) at least five step synthesis is required in order to create inbuilt phase transfer capability in the catalyst (ii) takes 1-10 hours for completion of epoxidation reaction (iii) post epoxidation work-up protocol is typical of homogeneous catalytic system and require chromatographic separation of the catalyst and the product epoxide.
The main object of the present invention is to provide a process for the
preparation of novel chiral SALEN transition metal catalyst useful in enantioselective epoxidation of prochiral olefins which obviates the drawbacks as detailed above.
Another object of the present invention is to provide a process for the synthesis of optically active transition metal complexes of the formula 1 where RpRg independently represent hydrogen atom, alkyls such as methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, alkoxys such as methoxy, ethoxy, halogens such as fluro, chloro, bromo, trifluromethyl, X may be none, methylene, alkyl substituted methylenes Where in alkyls such as methyl, ethyl, propyl, iso- propyl, n-butyl, A-B-A may be chirally pure vicinal diamines such S, S (+) 1, 2 diamino cyclohexane, R, R (-) 1, 2 diamino cyclohexane, S, S (-) 1, 2, diphenyl diamino ethane, R, R (+) 1,2 diphenyl diamino ethane, S (+) 1,2 diaminopropane, R (-) 1,2 diaminopropane and (m) may be 3-5 repetitive units and M can be transition metal ion such Cobalt(II), Manganese(III), Ruthenium (III), Nickel(II),

Copper(II), Chromium(III), Osmium(III) and Y represents anion like chloride, bromide, iodide, perchlorate, phosphorous hexaflouride and Z = oxygen or nitrogen, n = 0-1.
Still another object of the present invention is to provide the catalytic activity of the modified crural complexes to show epoxide conversion >99% and enable enantioselectivity in the range of 36 to 100%.
Yet another object of the present invention is to have a simple and cost effective synthesis of the modified chiral SALEN metal complexes devoid of many complicated steps.
Accordingly the present invention provides a process for the preparation of novel chiral SALEN transition metal catalyst of formula 1 useful in enantioselective epoxidation of
prochiral olefins
(Formula Removed)
Formula (1)
wherein R1-R8 independently represent hydrogen atom, alkyls such as methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, alkoxys such as methoxy, ethoxy, halogens such as fluoro, chloro, bromo, triflouromethyl, X may be none, methylene, alkyl substituted methylenes where in alkyls such as methyl, ethyl, propyl, iso- propyl, n-butyl, A-B-A is chirally pure vicinal diamines such as S, S (+) 1,2 diamino
cyclohexane, R, R (-) 1,2 diamino cyclohexane, S, S (-) 1,2, diphenyl diamino ethane, R, R (+) 1,2, diphenyl diamino ethane, S (+) 1,2 diaminopropane, R (-) 1,2 diaminopropane and (m) may be 3-5 repetitive units and M is transition metal ion selected from Cobalt(II), Manganese (III), Ruthenium (III), Nickel(II), Copper(II), Chromium(III), Osmium(III) and Y represents anion selected from chloride, bromide, iodide, perchlorate, phosphorous hexaflouride and Z = oxygen or nitrogen, n = 0-1, the said process comprises: (i) coupling of substituted salicylaldehyde with aliphatic aldehyde or ketone in presence of acid by conventional methods to give polymerizable substituted bis-salicylaldehyde then reacting with a chiral diamine using conventional condensation reaction to obtain chiral Schiff base ligand; (ii) refluxing the said Schiff base ligand with transition metal salt in an organic solvent such as herein described till completion of reaction under inert atmosphere; (iii) allowing the reaction mixture to cool at room temperature under aerobic conditions; (iv) adding a source of anion and recovering chiral SALEN catalyst so formed by known precipitation method.
In an embodiment of the present invention the substituted aldehydes used may be selected from 3-alkyl salicylaldehyde such 3-methyl salicylaldehyde, 3-ethyl salicylaldehyde, 3-n-propyl salicylaldehyde, 3-iso-propyl salicylaldehyde, 3-n-butyl salicylaldehyde, 3-iso-butyl salicylaldehyde, 3-tert-buty\ salicylaldehyde, halo salicylaldehyde such as 3-flouro salicylaldehyde, 3-chloro salicylaldehyde, 3-bromo salicylaldehyde, 3-iodo salicylaldehyde, 3-triflouromethyl salicylaldehyde, alkoxy salicylaldehyde such as 3-methoxy salicylaldehyde, 3-ethoxy salicylaldehyde and nitrogen containing such as 3-nitro salicylaldehyde.
In another embodiment of the present invention the coupling reaction may be selected from a temperature in the range 50-150° C.
In yet another embodiment of the present invention the aldehyde/ketone used may be selected from formaldehyde, paraformaldehyde, trioxane, acetone, 2-butanone, 2-pentanone, 3-pentanone, or mixture thereof.
In still another embodiment of the present invention the acid used may be selected from acetic acid, hydrochloric acid, hydrofluoric acid and sulfuric acid and mixture thereof.
In another embodiment of the present invention the transition metal salt used may be selected from manganese, cobalt, nickel, iron, chromium, ruthenium, osmium, copper.
Yet another embodiment of the present invention the organic solvent used may be selected from alcoholic solvent such as methanol, ethanol, propanol, butanol, halo solvents such as dichloromethane, 1,2 dichloroethane, chloroform or a mixture there of.
In still another embodiment of the present invention the post reflux cooling in presence of air may be augmented by bubbling/and or exposed to oxygen, air and the mixture there of.
In another embodiment of the present invention, the counter ion used may be selected from alkali metal halide such as lithium chloride, sodium chloride, potassium chloride, lithium bromide, sodium bromide, potassium bromide, lithium iodide, sodium iodide, potassium iodide or alkali metal perchlorate such as lithium perchlorate, sodium perchlorate, potassium perchlorate or alkali metal hexaflourophosphate such as potassium hexaflourophosphate.
In the process of the present invention, the syntheses of modified chiral Schiff
base derived from specially designed polymerisable salicylaldehyde was carried out using appropriate commercially available phenols by first introducing aldehyde group followed by coupling reaction in presence of aldehyde such as formaldehyde, paraformaldehyde, trioxane or mixture thereof in presence of hydrochloric acid, acetic acid and sulfuric acid to give the desired polymerisable substituted salicylaldehyde which was then interacted with appropriate commercially available chiral diamines in a solvent such as ethanol and methanol, nitriles such as acetonitrile and propionitrile, halogenated hydrocarbon such as dichloromethane, chloroform and 1,2 dichloroethane most preferably ethanol to give rise the modified chiral Schiff bases which are recrystallized with appropriate solvents and characterized by elemental analysis, IR, H NMR spectroscopy before these are used for the synthesis of the metal complexes which are prepared by thus synthesised chiral Schiff base compounds by dissolving or suspending one of these in an alcoholic solvent such as methanol, ethanol, a nitrile solvent such as acetonitrile, propionitrile or a halogenated hydrocarbon such as dichloromethane, chloroform and 1,2 dichloroethane most preferably ethanol and methanol and mixture thereof followed by addition of metal salt in an amount of 0.5-10 molar equivalent preferably 1-3 molar equivalent initially under inert atmosphere finally under aerobic condition to yield desired optically active complex although if required acetate ion may be replaced by chloride, hexaflourophosphate to give the complexes used as catalysts for the epoxidation of non-mnctionalised prochiral alkenes with several terminal oxidants such as sodium hypochlorite, hydrogen peroxide, alkyl hydroperoxide, molecular oxygen (with sacrificial reductant), per benzoic acid, such as m-chloro per benzoic acid aryl iodosyl benzene, oxone more preferably sodium hypochlorite, hydrogen peroxide , oxone, tetrabutyl ammonium hydroxide, m-chloro per
benzole acid and cheaper cooxidant/ axial base/ additive such as substituted and non substituted pyridine N-oxide, cyclic ethers such as 1,4 dioxane, furan, pyrans, dimethyl sulphoxide, inorganic salts of carboxylic acid such sodium acetate, ammonium acetate, sodium benzoate and sodium bicarbonate, imidazole, substituted imidazole most preferably pyridine N-oxide and an alkylated substituted and unsubstituted alkyl imidazoles in solvents like halohydrocarbon preferably dichloromethane, 1,2 dichloroethane or alkyl nitrile preferably acetonitrile, propionitrile, alcoholic solvent more preferably dichloro methane or the mixture of methanol and dichloromethane which showed catalytic activity for epoxide conversion >99% and enable enantioselectivity in non functionalised olefins such as styrene, chromene and indene in the range of 36 - 100% in a relatively shorter period of time in 1 to 6 hours for non-functionalized olefins.
The activity of the catalyst in a metal base catalysed system is largely dependent on the availability of the active sites to the reactants. The chemo and enantio selectivity of the system depends on mode of approach of the substrate, which is largely governed by shape, size and polarity of the substituents on the ligand system of the complex. The inventive steps involved in the present invention are i) the number of the active sites were increased by making polymeric complexes in order to achieve high catalytic activity; ii) simple synthetic procedures are used in the present invention to synthesise desired high molecular weight catalysts in three steps starting from the preferred salicylaldehyde; iii) high molecular weight of catalysts enabled the work up protocol simpler as catalyst-product separation after completion of catalytic epoxidation reaction can be achieved by precipitation method using commonly used non-polar solvents; iv) the time period of the
epoxidation reaction was reduced to 1-6 hours from the previously reported 1-10 hours, v) high conversion (>99%) and enantiomeric excess's (ee's) (35->99%) were achieved with cheaper oxidant like sodium hypochlorite. vi) cheaper axial base like pyridine N-oxide was employed in lower molar ratios (5 equivalent with respect to the catalyst).
The following examples are given by way of illustration of the present invention and therefore should not be construed to limit the scope of the present invention.
In a typical synthesis of the preferred optically active transition metal complexes as catalysts are described in following examples, in general appropriate substituted polymerizable salicylaldehydes are prepared by using simple synthetic procedures. These polymerizable salicylaldehydes are interacted with appropriate chiral diamines to form novel improved catalyst precursor chiral Schiff bases. The characterization of these ligands is accomplished by elemental analysis, IR and H NMR spectroscopy. These polymerizable Schiff base ligands were interacted with appropriate metal ion to get desired metal complexes used as chiral epoxidation catalyst.
EXAMPLE 1
Preparation of poly [(R,R )- N, N - bis {3-( 1,1-dimethyl ethyl) - 5 - methylene-salicylidine}l,2 - diphenyl-1,2 ethane diaminato (2-) manganese(III)] chloride (RRPTBSALDPMN)

Step I:
Synthesis of 5, 5 methylene-di-3-tertiary butyl salicylaldehyde
3-tert-buty\ salicylaldehyde (21.36 g) was treated with paraformaldehyde (l.8Og) in 16 ml glacial acetic acid and 2 ml sulfuric acid under nitrogen atmosphere. The resulting solution was allowed to heat up to 90° C with stirring for 24 hrs. The reaction mixture was poured into the cold water and allowed to stand overnight. The deposited dark brown solid was extracted with petroleum ether (3x 15 ml). The organic layer was dried over sodium sulfate. The dark brown compound was purified by silica gel column chromatography using hexane-ethyl acetate as eluent to yield light colored compound, yield 30.9 g, (70 %), m. p. 99-100°C, 1H NMR (CDC13, 200MHz)δ ppm 11.72(s, 2H, OH) 9.82(s, 2H, HCO), 7.37 (d, 2H, aromatic Jm==2.14), 7.14(d, 2H, aromatic, Jm =2.14), 3.93(s, 2H, methylene) 1.40(s, 9H, methyl). STEP II:
Poly [(R,R)-N,N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1,2-ethylene diamine]
The product from step I (7.36 g) and 1R,2R (-) 1,2 diphenyl ethylene diamine (4.24 g) were taken in absolute ethancl (40 ml) and refluxed for 2.5 hours yielding yellow colored oligomeric compound. It was filtered and washed with ethanol and dried in vacuum, Yield 8.84 g, 85%, m. p, 220°C. Elemental analysis, single unit C37H40N2O2. IR (KBr), (H-C=N) 1630 cm-1, 1H NMR (CDC13, 200MHz) δ ppm 13.56 (bs, 2H, OH), 8.22 (s, 2H, azomethine), 7.13 (bs, 10H, phenyl), 7.03 (d, 2H, aromatic), 6.67(d, 2H, aromatic), 4.64(s,2H, methylene), 3.66 (s, 2H, asymmetric), 1.34(s, 18H, t-butyl). STEP III:
The product from step II (4.87 g) was taken in 40 ml of dichloromethane and was interacted with ethanolic solution of (4.41 g) Manganese acetate under reflux condition in an inert atmosphere for 6 hours. After completion of reaction, the reaction mixture was cooled to room temperature, lithium chloride (1.13 g) was added and the mixture was allowed to stir for 5 hours, while bubbling air and filtered. The solvent was completely evaporated from the filtrate and the residue was extracted with dichloromethane (50 ml). The organic layer was washed with water, brine and dried over sodium sulfate. After partial removal of dichloromethane the desired complex (1) was precipitated by the addition of petroleum ether (40:60) and dried under vacuum. Yield, 5.27 g: 90%, elemental analysis, C37H40 ClN2O3Mn, IR (KBr) v(H-ON) 1590.
EXAMPLE 2
Preparation of poly [(S,S)-N, N -bis {3-(l,l-dimethylethyl)-5-methylene-salicylidine}l, 2 - diphenyl-1,2 ethane diaminato (2-) manganese (III) chloride] (SSPTBSALDPMN) STEP I:
Poly [(S,S)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1, 2-ethylene diamine]
5, 5 methylene-di-3-tertiary butyl salicylaldehyde (7.36 g) and 1S.2S (-) 1,2-diphenylethylene diamine (4.24 g) were taken in absolute ethanol (40 ml) and refluxed for 2-3 hours yielding yellow colored oligomeric Schiff base. It was filtered and washed with ethanol and dried in vacuum. Yield 8.84g, 85%, m.p. 220°C, elemental analysis, C37H40N2O2. 'H NMR (CDC13, 200MHz) δ ppm 13.56 (bs, 2H, OH), 8.22 (s, 2H, azomethine), 7.13 (bs, 10H, phenyl), 7.03 (d, 2H, aromatic), 6.67(d, 2H, aromatic), 4.64(s, 2H, methylene), 3.66 (s, 2H, asymmetric), 1.34(s, 18H, t-butyl).
STEP II:
The product from step I of example 2 (4.87 g) in 40 ml dichloromethane was refluxed with (4.4 Ig) Manganese acetate in ethanol under inert atmosphere for 6 hours. After completion of reaction the reaction mixture was cooled to room temperature and lithium chloride (1.13 g) was added and the mixture was allowed to stir for 5 hours, while exposed to air and filtered. The solvent was completely evaporated from the filtrate and the residue was extracted with dichloromethane (50 ml). The organic layer was washed with water, brine and dried over sodium sulfate. After partial removal of dichloromethane the desired complex (2) was precipitated by the addition of petroleum ether (40:60) and dried under vacuum. Yield, 5.27 g: 90%, elemental analysis, C37H40 ClN2O3Mn, IR (KBr) v(H-ON) 1590.
EXAMPLE 3
Preparation of poly [(S,S)-N,N'-bis{3-(l,l-dimethylethyl)-5-methylene salicylidine} cyclohexene-l,2-diaminato (2-) manganese(III) chloride] (SSPTBSALHEXMN) STEP I:
5, 5 methylene-di-3-tertiary butyl salicylaldehyde (6.62 g) and 1S,2S (+) 1,2-diaminocyclohexane (2.05 g) were taken in absolute ethanol (50 ml) and refluxed for 2 hours to obtain oligomeric [(S,S)-N,N'-bis-{3-(l,l-dimethylethyl)-5-methylene salicylidine} cyclohexene 1,2 -diamine]. It was filtered and washed with ethanol and dried in vacuum. Yield, 6.82 g (85%), m. p., 218°C, elemental analysis, C29H38N2O2. 1H NMR (CDC13, 200 MHz) δ ppm 13.77 (bs, 2H, OH), 8.21 (s, 2H, azomethine), 6.74 (d, 2H, aromatic, Jm =2Hz), 7.05(d, 2H, aromatic, Jm =2Hz), 3.68 (s, 2H, methylene), 3.29(bm, 2H, asymmetric) 1.87 (m, 8H, cyclohexane), 1.36(s, 8H, t- butyl).
STEP II:
The product from step I (3.99 g) in ethanol was allowed to react with Manganese acetate (4.41 g) under reflux condition in an inert atmosphere for 6 hours. After completion of reaction, the reaction mixture was cooled to room temperature, lithium chloride (1.13 g) was added and the mixture was allowed to stir for another 5 hours, while bubbling oxygen and filtered. The solvent was removed from the filtrate and the residue was extracted with dichloromethane (50 ml). The organic layer was washed with water, brine and dried over sodium sulfate. After partial removal of dichloromethane the desired complex (1) was precipitated by the addition of petroleum ether (40:60) and dried under vacuum. Yield, 4.55 g: 92 %, elemental analysis, C29H38 ClN2O3Mn, IR (KBr) v(H-C=N) 1590.
EXAMPLE 4
Preparation of poly [(.R,R)-N,N'-bis{3-(1,1-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) manganese(III) chloride] (RRTBSALHEXMN) STEP I:
5, 5 methylene-di-3-tertiary butyl salicylaldehyde (6.62 g) and JR,2R (+) 1,2-diaminocyclohexane (2.05 g) were taken in absolute ethanol (50 ml) and refluxed for 2.5 hours to obtain yellow colored oligomeric compound poly {(R,R)-N,N' bis {3(1,1-dimethyl ethyl)-5-methylene salicylidine} cyclohexenel,2 diamine}. It was filtered and washed with ethanol and dried in vacuum, Yield, 6.88 g (84 %), m. p, 218°C, elemental analysis, C29H38N2O2. 1H NMR (CDC13, 200 MHz) δ ppm 13.77 (bs, 2H, OH), 8.21 (s, 2H, azomethine), 6.74 (d, 2H, aromatic, Jm =2Hz), 7.05(d, 2H, aromatic, Jm =2Hz), 3.68 (s, 2H, methylene), 3.29(bm, 2H, asymmetric) 1.87 (m, 8H, cyclohexane), 1.36(s, 8H, t-
butyl). STEP II:
The product from step I (3.99 g) of the example 4 in ethanol was allowed to react with Manganese acetate (4.41 g) under reflux condition in an inert atmosphere for 6 hours. After completion of reaction, the reaction mixture was cooled to room temperature, lithium chloride (1.13 g) was added and the mixture was further stirred for 5 hours, while exposed to air and filtered. The solvent was removed from the filtrate and the residue was extracted with dichloromethane (50 ml). The organic layer was washed with water, brine and dried over sodium sulfate. After partial removal of dichloromethane the desired complex (1) was precipitated by the addition of petroleum ether (40:60) and dried under vacuum. Yield, 4.45 g: 90%, elemental analysis, C29H38ClN2O3Mn, IR (KBr) v(H-C=N) 1590.
EXAMPLE-5
Preparation of poly [(R,R)-N,N'-bis{3-(l,l-dimethylethyl) -5- methylene salicylidine}
cyclohexene-l,2-diaminato (2-) manganese(III) hexafluorophosphate]
(RRTBSALHEXMN) STEP I:
5, 5 methylene-di-3-tertiary butyl salicylaldehyde (6.62 g) and 1R,2R (+) 1,2-diaminocyclohexane (2.05 g) were taken in absolute ethanol (50 ml) and refluxed for 2.5 hours to obtain yellow colored oligomeric compound poly |(R,R)-N,N' bis (3(1,1-dimethyl ethyl)-5-methylene salicylidine} cyclohexenel,2 diamine}. It was filtered and washed with ethanol and dried in vacuum, Yield, 6.88 g (84 %), m. p, 218°C, elemental analysis, C29H38N2O2. 'H NMR (CDC13, 200 MHz) δ ppm 13.77 (bs, 2H, OH), 8.21 (s,
2H, azomethine), 6.74 (d, 2H, aromatic, Jm =2Hz), 7.05(d, 2H, aromatic, Jm =2Hz), 3.68 (s, 2H, methylene), 3.29(bm, 2H, asymmetric) 1.87 (m, 8H, cyclohexane), 1.36(s, 8H, t-butyl). STEP II:
The product from step I (3.99 g) of the example 4 in ethanol was allowed to react with manganese acetate (4.41 g) under reflux condition in an inert atmosphere for 6 hours. After completion of reaction, the reaction mixture was cooled to room temperature, lithium chloride (1.13 g) was added and the mixture was further stirred for 5 hours, while exposed to air and filtered. The solvent was removed from the filtrate and the residue was extracted with dichloromethane (50 ml). The organic layer was washed with water, brine, dried over sodium sulfate and filtered. The filtrate was stirred with potassium hexaflourophosphate (2.48 g) for 6 hours and after partial removal of dichloromethane the desired complex (1) was precipitated by the addition of petroleum ether (40:60) and dried under vacuum. Yield, 4.56 g: 90%, elemental analysis, C29H38F6lN2O3PMn, IR (KBr) v(H-C=N) 1590.
EXAMPLE- 6 Synthesis of 5, 5-(l', 1' dimethyl methylene)- di-3-tertiary butyl salicylaldehyde.
3-tertiary butyl salicylaldehyde (21.36g) was treated with acetone (6.95g) in 10 ml of 1:1 mixture of concentrated hydrochloric and sulphuric acid under argon atmosphere. The resulting solution was allowed to heat up to 55 C with stirring for two days. The reaction mixture was poured into crushed ice (200g) and allowed to stand over night. The
deposited dark colored sticky material was extracted with petroleum ether (3x 20ml). The organic layer was chromatographed using hexane-ethyl acetate as eluent to yield the off white compound, yield 5.92g (25%). Elemental analysis C25H31O4.
EXAMPLE-7 Synthesis of 5, 5 methylene-di-3-chloro salicylaldehyde
3-chloro salicylaldehyde (15.7 g) was treated with paraformaldehyde (1.5 g) in 16 ml glacial acetic acid and 2 ml sulfuric acid under nitrogen atmosphere. The resulting solution was allowed to heat up to 90° C with stirring for 24 hrs. The reaction mixture was poured into the cold water and al'owed to stand overnight. The deposited dark brown solid was extracted with hexane (3x 15 ml). The organic layer was dried over sodium sulfate. The dark gray compound was purified by silica gel column chromatography using hexane-ethyl acetate as eluent to yield light colored compound. Yield 9.8 g, (60 %). Elemental analysis C15H10Cl2O4.
EXAMPLE-8 Synthesis of 5, 5 methylene-di-3-methoxy salicylaldehyde
3-methoxy salicylaldehyde (15.0 g) was treated with paraformaldehyde (1.5 g) in 16 ml glacial acetic acid and 2 ml sulmric acid under nitrogen atmosphere. The resulting solution was allowed to heat up to 90° C with stirring for 24 hrs. The reaction mixture was poured into the cold water and allowed to stand overnight. The deposited dark brown solid was extracted with chloroform (3x 15 ml). The organic layer was dried over sodium sulfate. The dark brown compound was purified by silica gel column chromatography using hexane-dichloromethane as eluent to yield light colored compound. Yield, 6.3 g, (40%). Elemental analysis, C17H16O6.
EXAMPLE-9 Synthesis of 5, 5 methylene-di-3-nitro-salicylaldehyde
3-nitro salicylaldehyde (16.7 g) was treated with paraformaldehyde (1.5 g) in 16 ml glacial acetic acid and 2 ml sulfuric acid under nitrogen atmosphere. The resulting solution was allowed to heat up to 90° C with stirring for 24 hrs. The reaction mixture was poured into the cold water and allowed to stand overnight. The deposited dark brown solid was extracted with dichloromethane (3x 15 ml). The organic layer was dried over sodium sulfate. The dark brown compound was purified by silica gel column chromatography using hexane-dichloromethane as eluent to yield yellow colored compound, yield 10.3 g, (60 %),. Elemental analysis, C15H10N2O8
EXAMPLE 10
Preparation of poly [(R,R)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene-salicylidine}l,2 - diphenyl-1,2 ethane diaminato (2-) cobalt (II)]
Poly [R,R)-N,N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1,2- ethylene diamine] (0.544 g) and sodium acetate (0.164 g) was allowed to reflux in ethanol (25 ml) under inert atmosphere. To this refluxing solution hot and degassed solution of cobalt (II) acetate (0.249 g) in water (10 ml) was added and the mixture was allowed to reflux for 1.5 hours. A brick red precipitate of the desired complex was filtered and washed ethanol. Yield, 3.43 g (95 %), elemental analysis C37H38N2O2Co IR (KBr) v(H-C=N) 1590.
EXAMPLE 11 Poly [(S,S)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene-salicylidine}l,2 - diphenyl-1,2

ethane diaminato (2-) cobalt(II)]
Poly [(S,S)-N,N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1,2- ethylene diamine] (0.544 g) and sodium acetate (0.164 g) was allowed to reflux in ethanol (25 ml) under inert atmosphere. To this refluxing solution hot and degassed solution of cobalt (II) acetate (0.249 g) in water (10 ml) was added and the mixture was allowed to reflux for 1.5 hours. A brick red precipitate of the desired complex was filtered and washed ethanol. Yield, 3.30 g (91 %), elemental analysis C37H38N2O2Co, IR (KBr) v(H-C=N) 1590.
EXAMPLE 12
Preparation of poly [(S,S)-N,N'-bis{3(l,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) cobalt(II)]
Poly [(S,S)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1, 2- ethylene diamine] (0.446 g) and sodium acetate (0.164 g) was allowed to reflux in ethanol (25 ml) under inert atmosphere. To this refluxing solution hot and degassed solution of cobalt (II) acetate (0.249 g) in water (10 ml) was added and the mixture was allowed to reflux for 2 hours. A brick red precipitate of the desired complex was filtered and washed ethanol. Yield, 2.82 g (93 %),elemental analysis C29H36N2O2Co, IR (KBr) v(H-ON) 1590.
EXAMPLE 13
Preparation of poly [(R,R)-N,N'-bis{3(l,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) cobalt(II)]
Poly [(R,R)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1, 2- ethylene diamine] (0.446 g) and sodium acetate (0.164 g) was allowed to

reflux in ethanol (25 ml) under inert atmosphere. To this refluxing solution hot and degassed solution of cobalt (II) acetate (0.249 g) in water (10 ml) was added and the mixture was allowed to reflux for 2 hours. A brick red precipitate of the desired complex was filtered and washed ethanol. Yield, 2.76 g (91%), elemental analysis C29H36N2O2Co, IR (KBr) v(H-C=N) 1590.
EXAMPLE 14
Preparation of poly [(R,R)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene-salicylidine}l,2 - diphenyl-1,2 ethane diaminato (2-) nickel (II)]
Poly [(R,R)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1, 2- ethylene diamine] (0.544 g) was taken in 1:1 mixture of methanol and dichloromethane (20 ml) and was added to a solution of nickel acetate (0.249g in 20 ml dichloromethane). To this mixture triethylamine (0.89 ml) was added and the resulting solution was refluxed for 6 hours. After completion of reaction the solvent was removed. The residue was dissolved in dichloromethane, washed with water and brine and dried over sodium sulphate. Removal of solvent yielded the desired complex. Yield, 3.32 g (92%), elemental analysis C37H38N2O7Ni, IR (KBr) v(H-C=N) 1590.
.EXAMPLE 15
Poly [(S,S)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene-salicylidine}l,2 - diphenyl-1,2 ethane diaminato (2-) nickel(II)]
Poly [(S,S)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1, 2- ethylene diamine] (0.544 g) was taken in 1:1 mixture of methanol and dichloromethane (20 ml) and was added to a solution of nickel acetate (0.249g in 20 ml dichloromethane). To this mixture triethylamine (0.89 ml) was added and the resulting
solution was refluxed for 6 hours. After completion of reaction the solvent was removed. The residue was dissolved in dichloromethane, washed with water and brine and dried over sodium sulphate. Removal of solvent yielded the desired complex. Yield, 3.44 g (95%), elemental analysis C37H38N2O2Ni, IR (KBr) v(H-C=N) 1590.
EXAMPLE 16
Preparation of poly [(S,S)-N,N'-bis{3(l,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) nickel(II)]
Poly [(S,S)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1, 2- ethylene diamine] (0.446 g) was taken in 1:1 mixture of methanol and dichloromethane (20 ml) and was added to a solution of nickel acetate (0.249g in 20 ml dichloromethane). To this mixture triethylamine (0.89 ml) was added and the resulting solution was refluxed for 6 hours. After completion of reaction the solvent was removed. The residue was dissolved in dichloromethane, washed with water and brine and dried over sodium sulphate. Removal of solvent yielded the desired complex. Yield, 2.76 g, (91%), elemental analysis C29H36N2O2 Ni, IR (KBr) v(H-C=N) 1590.
EXAMPLE 17
Preparation of poly [(R,R)-N,N'-bis{3(l,l-dimethylethyl) -5- methylene salicylidine} cyclohexene-l,2-diaminato (2-) nickel (II)]
Poly [(R,R)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene salicylidine} 1,2-diphenyl 1, 2- ethylene diamine] (0.446 g) was taken in 1:1 mixture of methanol and dichloromethane (20 ml) and was added to a solution of nickel acetate (0.249g in 20 ml dichloromethane). To this mixture triethylamine (0.89 ml) was added and the resulting solution was refluxed for 6 hours. After completion of reaction the solvent was removed.
The residue was dissolved in dichloromethane, washed with water and brine and dried over sodium sulphate. Removal of solvent yielded the desired complex. Yield, 2.85 g, (94%), elemental analysis C2qH36N2O2Ni, IR (KBr) v(H-C=N) 1590. Following catalysts are also prepared by the same process as herein described. Preparation of poly [(S,S)-N, N'-bis {3-(l,l-dimethylethyl)-5-methylene-salicylidine}l,2
- diphenyl-1,2 ethane diaminato (2-) chromium (III) chloride]
Yield, 3.45 g (91%), elemental analysis C37H38ClN2O2Cr, IR (KBr) v(H-C=N) 1590.
Poly [R,R)-N,N'-bis {3-(l,l-dimethylethyl)-5-methylene-salicylidine}l,2 - diphenyl-1,2
ethane diaminato (2-) chromium(III) chloride]
Yield, 3.55 g (94%), elemental analysis C37H3SClN2O2Cr, IR (KBr) v(H-C=N) 1590.
Preparation of poly [(S,S)-N,N'-bis{3-(l,l-dimethylethyl) -5- methylene salicylidine}
cyclohexene-l,2-diaminato (2-) chromium (III) chloride]
Yield, 2.94 g, (92%), elemental analysis C29H36C1N2O2 Cr, IR (KBr) v(H-C=N) 1590.
Preparation of poly [(^,/?)-N,N'-bis{3-(l,l-dimethylethyl) -5- methylene salicylidine}
cyclohexene-l,2-diaminato (2-) chromium (III) chloride]
Yield, 3.04 g, (95%), elemental analysis C2l)H36ClN2O2Cr, IR (KBr) v(H-C=N) 1590.
Preparation of poly [S,S)-N,N'-bis {3-(l,l-dimethylethyl) -5- methylene salicylidine} 1,2
- diphenyl-1,2 ethane diaminato (2-) copper (II)]
Yield, 3.35 g, (92%), elemental analysis C37H38N2O2Cu, IR (KBr) v(H-C=N) 1590. poly[ (R,R)-N, N'-bis {3-(l,l-dimethylethyl) -5- methylene-salicylidine}l,2 - diphenyl-1,2 ethane diaminato (2-) copper(II) Yield, 3.27 g, (90%), elemental analysis C37H38N2O2Cu, IR (KBr) v(H-C=N) 1590.
Preparation of poly [(5,5)-N,N'-bis{3(l,l-dimethylethyl) -5- methylene salicylidine}
cyclohexene-l,2-diaminato (2-) copper(II)]
Yield, 2.88 g, (94%), elemental analysis C29H36N2O2 Cu, IR (KBr) v(H-C=N) 1590.
Preparation of poly [(R,R)-N,N'-bis{3(l,l-dimethylethyl) -5- methylene
salicylidine}cyclohexene-l,2-diaminato (2-) copper (II)]
Yield, 2.82 g, (92%), elemental analysis C29H36N2O2Cu, IR (KBr) v(H-ON) 1590.
Preparation of Potassium poly [(,S,S,)-N,N'-bis {3-(l,l-dimethylethyl) -5- methylene-
salicylidine} 1,2 - diphenyl-1,2 ethane diaminato (2-) ruthenium (III) dichloride]
Yield, 4.30 g, (95 %), elemental analysis C37H38Cl2N2O2RuK , IR (KBr) v(H-C=N) 1590.
Potassium Poly [(R,R)N,N'-bis {3-(l,l-dimethylethyl) -5- methylene-salicylidine}l,2 -
diphenyl-1,2 ethane diaminato (2-) ruthenium (III) dichloride]
Yield, 4.07 g, (90%), elemental analysis C37H38Cl2N2O2RuK , IR (KBr) v(H-ON) 1590.
Preparation of Potassium poly [(S,S)-KN'-bis{3-(1,l-dimethylethyl) -5- methylene
salicylidine} cyclohexene-l,2-diaminato (2-) ruthenium (III) dichloride]
Yield, 3.67 g, (93%), elemental analysis C29H38Cl2N2O2RuK, IR (KBr) v(H-C=N) 1590.
Preparation of Potassium poly [(R,R) - N,N'-bis {3-(l,l-dimethylethyl) - 5 - methylene
salicylidine}cyclohexene-l,2-diaminato (2-) ruthenium (III) dichloride]
Yield, 3.55 g, (90%), elemental analysis C29H36Cl2N2O2RuK, IR (KBr) v(H-C=N) 1590.
Preparation of Potassium poly [(S,S) - N,N'-bis |3-(l,l-dimethylethyl) - 5 - memylene-
salicylidine} 1, 2- diphenyl-1, 2 ethane diaminato (2-) Osmium (III) dichloride]
Yield, 4.70 g, (93 %), elemental analysis C37H38Cl2N2O2OsK IR (KBr) v(H-C=N) 1590.
Preparation of Potassium poly [(R,R)-N,N' -bis {3-(l,l-dimethylethyl) -5- methylene-
salicylidine} 1,2- diphenyl-1,2 ethane diaminato (2-) Osmium (III) dichloride]
Yield, 4.60 g, (91%), elemental analysis C37H38Cl2N2O2OsK
Preparation of Potassium poly [(5,5)-N,N'-bis {3(l,l-dimethylethyl) -5- methylene
salicylidine} cyclohexene-l,2-diaminato (2-) Osmium (III) dichloride]
Yield, 4.12 g,(92%), elemental analysis, C29H36Cl2N2O2Os K , IR (KBr) v(H-C=N) 1590.
Preparation of Potassium poly [(R,R)-N,N'-bis {3-(l,l-dimethylethyl) -5- methylene
salicylidine} cyclohexene-l,2-diaminato (2-) Osmium (III) dichloride]
Yield, 4.03 g, (93%), elemental analysis, C29H36Cl2N2O2Os K, IR (KBr) v(H-ON) 1590.
The main advantages of the present invention are:
1. Synthesis of high molecular weight optically active transition complexes and their
precursor ligands involve simple reaction procedures and conditions.
2. Commercial LR grade ingredients required no further purification.
3. Final work up protocol of the post catalytic run is simple and requires simply
precipitation of the catalyst just by addition of a non-polar organic solvents.
4. In absence of any detectable amount of side products along with high conversions (on
GC and NMR scale) the final work up protocol is further easy separation of the
catalyst which is quite difficult in other homogeneous system.
5. Good isolated yields of epoxides are achievable with inexpensive oxidation reagents
under mild reaction conditions.
6. Reaction rates are significantly faster than reported so far with these types of catalysts
especially with the extent of selectivity disclosed here.
7. The phase transfer reagents alkyl ammonium halide can be used with biphasic catalytic runs to increase the rate of epoxidation with improved enantioselection in
some cases.

We Claim:
1. A process for the preparation of novel chiral SALEN transition metal catalyst of formula 1 useful in enantioselective epoxidation of prochiral olefins
(Formula Removed)
Formula (1)
wherein R1-R8 independently represent hydrogen atom, alkyls such as methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, alkoxys such as methoxy, ethoxy, halogens such as fluoro, chloro, bromo, triflouromethyl, X may be none, methylene, alkyl substituted methylenes where in alkyls such as methyl, ethyl, propyl, iso- propyl, n-butyl, A-B-A is chirally pure vicinal diamines such as S, S (+) 1,2 diamino cyclohexane, R, R (-) 1,2 diamino cyclohexane, S, S (-) 1,2, diphenyl diamino ethane, R, R (+) 1,2, diphenyl diamino ethane, S (+) 1,2 diaminopropane, R (-) 1,2 diaminopropane and (m) may be 3-5 repetitive units and M is transition metal ion selected from Cobalt(II), Manganese (III), Ruthenium (III), Nickel(II), Copper(II), Chromium(III), Osmium(III) and Y represents anion selected from chloride, bromide, iodide, perchlorate, phosphorous hexaflouride and Z = oxygen or nitrogen, n = 0-1, the said process comprises: (i) coupling of substituted salicylaldehyde with aliphatic aldehyde or
ketone in presence of acid by conventional methods to give polymerizable substituted bis-salicylaldehyde then reacting with a chiral diamine using conventional condensation reaction to obtain chiral Schiff base ligand; (ii) refluxing the said Schiff base ligand with transition metal salt in an organic solvent such as herein described till completion of reaction under inert atmosphere; (iii) allowing the reaction mixture to cool at room temperature under aerobic conditions; (iv) adding a source of anion and recovering chiral SALEN catalyst so formed by known precipitation method.
2. A process as claimed in claim 1 wherein substituted salicylaldehydes used selected from 3-alkyl salicylaldehyde such 3 -methyl salicylaldehyde, 3 -ethyl salicylaldehyde, 3-n-propyl salicylaldehyde, 3-iso-propyl salicylaldehyde, 3-n-butyl salicylaldehyde, 3-iso-butyl salicylaldehyde, 3-rert-butyl salicylaldehyde, halo salicylaldehyde selected from 3-flouro salicylaldehyde, 3-chloro salicylaldehyde, 3-bromo salicylaldehyde, 3-iodo salicylaldehyde, 3-triflouromethyl salicylaldehyde, alkoxy salicylaldehyde such as 3-methoxy salicylaldehyde, 3-ethoxy salicylaldehyde and nitrogen containing such as 3-
3. A process as claimed in claims 1 and 2 wherein the coupling reaction is
at a
temperature in the range 50-1 50 ° C preferably at 90-95 ° C.
4. A process as claimed in claims 1 to 3 wherein the aldehyde/ketone used is selected
from formaldehyde, paraformaldehyde, trioxane, acetone, 2-butanone, 2-pentanone, 3-
pentanone preferably paraformaldehyde.
5. A process as claimed in claims 1to 4 the acid used is selected from mineral acids
selected from hydrochloric acid, sulphuric acid, carboxylic acid selected from acetic acid
and mixture thereof preferably glacial acetic acid and sulfuric acid.
6. nitro salicylaldehyde preferably 3-tert-butyl salicylaldehyde.carried
7. A process as claimed in claims 1 to 5 wherein the transition metal salt used is selected
from manganese, cobalt, nickel, chromium, ruthenium, osmium and copper.
8. A process as claimed in claims 1 to 6 wherein the organic solvent used is selected
from alcoholic solvents such as methanol, ethanol, propanol, butanol, halo solvents
selected from dichloromethane, 1,2 dichloethane, chloroform or a mixture thereof.
9. A process as claimed in claims 1 to 7 wherein reaction mixture is cooled by bubbling
air or exposed to oxygen and mixture thereof.
10. A process as claimed in claims 1 to 8 wherein the source of anion is selected from
alkali metal halide or alkali metal perchlorate or alkali metal hexaflourophosphate
preferably chloride by adding lithium chloride.
10. A process for the preparation of novel chiral SALEN transition metal catalyst useful
in enantioselective epoxidation of prochiral olefins substantially as herein described with reference to the examples of formula 1 in this specification.

Documents:

1160-del-2000-abstract.pdf

1160-del-2000-claims.pdf

1160-del-2000-correspondence-others.pdf

1160-DEL-2000-Correspondence-PO.pdf

1160-del-2000-description (complete).pdf

1160-del-2000-form-1.pdf

1160-del-2000-form-19.pdf

1160-del-2000-form-2.pdf

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Patent Number

217134

Indian Patent Application Number

1160/DEL/2000

PG Journal Number

18/2008

Publication Date

02-May-2008

Grant Date

25-Mar-2008

Date of Filing

15-Dec-2000

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	NOOR-UL HASAN KHAN	CENTRAL SALT & MARINE CHEMICALS RESEARCH INSTITUTE, GIJUBHAI BADHEKA MARG, BHAVNAGAR-364002, GUJARAT, INDIA.
2	SUNIL TRIBHOVAN DAS PATEL	CENTRAL SALT & MARINE CHEMICALS RESEARCH INSTITUTE, GIJUBHAI BADHEKA MARG, BHAVNAGAR-364002, GUJARAT, INDIA.
3	RAKSH VIR JASRA	CENTRAL SALT & MARINE CHEMICALS RESEARCH INSTITUTE, GIJUBHAI BADHEKA MARG, BHAVNAGAR-364002, GUJARAT, INDIA.
4	RUKHSANA ILYAS KURESHY	CENTRAL SALT & MARINE CHEMICALS RESEARCH INSTITUTE, GIJUBHAI BADHEKA MARG, BHAVNAGAR-364002, GUJARAT, INDIA.
5	SAYED HASAN RAZI ABDI	CENTRAL SALT & MARINE CHEMICALS RESEARCH INSTITUTE, GIJUBHAI BADHEKA MARG, BHAVNAGAR-364002, GUJARAT, INDIA.
6	PARAMESHWAR KRISHNAN IYER	CENTRAL SALT & MARINE CHEMICALS RESEARCH INSTITUTE, GIJUBHAI BADHEKA MARG, BHAVNAGAR-364002, GUJARAT, INDIA.

PCT International Classification Number

C07F 013/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA