The present invention provides an improved process for the preparation of a compound of formula (I), which comprises the steps of: formula (I), (a) reacting isovaleraldehyde of formula (II) and alkyl cyanoacetate of formula (III) optionally in presence of salts of weak acid and weak base or weak base in a suitable solvent to get 2-cyano-5-methyl-hex-2-enoic acid alkyl ester of formula (IV); (b) reacting 2-cyano-5-methyl-hex-2-enoic acid alkyl ester of formula (IV) with a suitable cyanide source in water or in an organic solvent or mixture thereof to get 2-isobutylsuccinonitrile of formula (V); (c) obtaining optionally 2-isobutylsuccinonitrile of formula (V) by reacting isovaleraldehyde of formula (II) and alkyl cyanoacetate of formula (III) in presence of suitable cyanide source in water or in an organic solvent or mixture thereof in single step; (d) converting 2-isobutylsuccinonitrile of formula pa (V) to racemic 3-cyano-5-methyl-hexanoic acid or salt thereof of formula (VI) with a genetically modified nitrilase enzyme (Nit pt 9N_56_2) in water or optionally with an organic co-solvent at appropriate pH and temperature; (e) converting racemic 3-cyano-5-methyl-hexanoic acid or salt thereof of formula (VI) to racemic alkyl 3-cyano-5-methyl-hexanoate of formula (VII) by treatment with alcohol (R3OH) and acidic catalyst or alkyl halide (R3X) in presence of a base in a suitable solvent or a mixture of solvents thereof; (f) obtaining (S)-alkyl 3-cyano-5-methyl-hexanoate of formula (VIII) and (R)-3-cyano-5-methyl-hexanoic acid or salt thereof of formula (X) by enzymatic enantioselective hydrolysis in water or organic solvent or a mixture thereof from racemic alkyl 3-cyano-5-methyl-hexanoate of formula (VII); (g) obtaining optionally the compound of formula (VII) by racemizing unwanted (R)-3-cyano-5-methyl-hexanoic acid or salt thereof of formula (X) or substantially enriched (R)-3-cyano-5-methyl-hexanoic acid salt thereof of formula (X) in presence of a base in organic solvent or a mixture thereof; (h) converting (S)-alkyl 3-cyano-5-methyl-hexanoate of formula (VIII) to pregabalin of formula (I) by hydrolyzing ester group with suitable alkali or alkaline earth metal base followed by hydrogenation optionally in one pot in a solvent selected from water or other organic solvents or a mixture thereof in presence of a suitable hydrogenation catalyst.
Novel asymmetric synthesis of (S)-(+)-3-(aminomethyl)-5-methylhexanoic acid
申请人:Kansal Kumar Vinod
公开号:US20070197827A1
公开(公告)日:2007-08-23
The invention encompasses processes for the synthesis of (S)-(+)-3-(aminomethyl)-5-methylhexanoic acid, (S)-Pregabalin, and intermediates of (S)-Pregabalin.
Novel asymmetric synthesis of (S)-(+)-3-(Aminomethyl)-5-methylhexanoic acid
申请人:Kansal Vinod Kumar
公开号:US20090062562A1
公开(公告)日:2009-03-05
The invention encompasses processes for the synthesis of (S)-(+)-3-(aminomethyl)-5-methylhexanoic acid, (S)-Pregabalin, and intermediates of (S)-Pregabalin.
Synthesis of (S)-(+)-3-(aminomethyl)-5-methyl hexanoic acid
申请人:Kansal Vinod Kumar
公开号:US20080306292A1
公开(公告)日:2008-12-11
Provided are syntheses of (S)-(+)-3-(aminomethyl)-5-methylhexanoic acid, (S)-Pregabalin via a chiral intermediate of the following formula 4
wherein Ar is a C
6-10
aromatic group, R is a straight or branched C
1-4
alkyl, ester, or carboxylic acid, and R
1
is a straight or branched C
1-5
alkyl, aralkyl, or substituted aralkyl.
Novel asymmetric synthesis of (s)-(+)-3-(AMINOMETHYL)-5- methylhexanoic acid
申请人:Kansal Vinod Kumar
公开号:US20100081841A1
公开(公告)日:2010-04-01
The invention encompasses processes for the synthesis of (S)-(+)-3-(aminomethyl)-5-methylhexanoic acid, (S)-Pregabalin, and intermediates of (S)-Pregabalin.