Patent ID: 7803586

Claim:
A process for the preparation of an enantiomerically enriched compound of formula I and pharmaceutically acceptable salts thereof in which R 1 represents chloro, fluoro, or hydroxy; which comprises hydrolysing a compound of formula II in which R 1 is as initially defined; X is O or S; and, R 2 is a C 1-10 alkyl group, a C 1-6 haloalkyl, a C 2-6 alkenyl group, an aryl, or an arylC 1-6 alkylene group, with or without additional hetero substitution; with a lipase selected from the group consisting of (a) Mucor miehei lipase, Candida rugosa lipase, Candida cylindracia lipase, Thermomyces lanuginosa lipase, Mucor javanicus lipase, and Rhizopus delemar lipase, when X is O; and, (b) Pseudomonas cepacia lipase, when X is S; in the presence of a reaction medium at a temperature in the range of 10-60° C.