Process for separation of optical isomer of alpha-substituted carboxylic acid

PURPOSE: To obtain the subject compound of high optical purity useful as an antiinflammatory agent in high yield by allowing an α-substituted carboxylic racemic ester to react with an esterase originating from a specific bacterium that can selectively hydrolyze one enantiomer and isolating the product after the reaction. CONSTITUTION: A racemic ester of an α-substituted carboxylic acid of formula I [R is a (substituted) phenyl of formula II (R 2 and R 3 are each H, a 1-8C alkyl, a 2-4C alkenyl, phenyl, a alkoxy), a (substituted) naphthyl of formula III; R 1 and R 4 are each a 1-4C alkyl] is allowed to react with cells of a bacterium that can selectively hydrolyze one enantiomer of the starting ester as Brevibacterium, Bacteridium, Micrococcus and Bacillus or an esterase enzyme therefrom. Then, the acid in the form of one enantiomer is separated from the unreacting ester whereby the objective optical isomer of an α-substituted carboxylic acid of high optical purity corresponding to formula IV is obtained in high yield. COPYRIGHT: (C)1993,JPO