Patent ID: 6440721
Filing Date: 2002-08-27
Classification: C12P,Y02P

Abstract:
A method for preparing an R- or S-form &agr;-substituted heterocyclic carboxylic acid and a counter enantiomeric form of &agr;-substituted heterocyclic carboxylic acid ester thereto, comprising the steps of:reacting a racemic &agr;-substituted heterocyclic carboxylic acid with alcohol to give a racemic &agr;-substituted heterocyclic carboxylic acid ester having the following chemical formula 1: wherein,R1 is selected from the group consisting of substituted or unsubstituted alkyl or alkenyl containing 1 to 6 carbon atoms, benzyl, cycloalkyl containing 3 to 6 carbon atoms, substituted or unsubstituted arylalkyl, and substituted or unsubstituted heteroarylalkyl, X represents O, S or NH, and n is an integer of 1 to 3; optically resolving the racemate of the formula 1 in an aqueous solution by use of an enzyme with enantioselectivity to hydrolyze either R-form or S-form of the racemate, thereby producing an R-form or S-form of &agr;-substituted heterocyclic carboxylic acid and a counter enantiomeric form of &agr;-substituted heterocyclic carboxylic acid ester thereto, said enzyme existing as a powder or an aqueous solution; extracting the unhydrolyzed &agr;-substituted heterocyclic carboxylic acid ester of the racemate with an organic solvent, followed by recovering the &agr;-substituted heterocyclic carboxylic acid ester from the organic phase and the &agr;-substituted heterocyclic carboxylic acid from the aqueous phase, respectively; and subjecting the recovered &agr;-substituted heterocyclic carboxylic acid ester in an organic solvent to hydrogenation under a constant hydrogen partial pressure at a constant temperature in the presence of a palladium catalyst on carbon (Pd/C), followed by recovering the resulting &agr;-substituted heterocyclic carboxylic acid.