PRODUCTION OF OPTICALLY ACTIVE 2-CHLOROMANDELIC ACID AND PRODUCTION INTERMEDIATE

摘要

PROBLEM TO BE SOLVED: To obtain an optically active 2-chloromandelic acid in high yield by reacting RS-chloromandelic acid with an optically active isomer of an amine as an optical resolution agent in a reaction medium to obtain a diastereomer salt, separating a diastereomer salt and decomposing the separated salt. SOLUTION: The objective compound is produced by reacting (A) (RS)-2- chloromandelic acid with (B) an optically active isomer of an amine of formula II (R1 and R2 are each H, CH3, NO2 or the like; the atom marked with *is an asymmetric carbon atom), e.g. an optically active N-benzyl-1- phenylethylamine as an optical resolution agent in (C) a reaction medium such as water or a lower alcohol to obtain a diastereomer salt such as (R)-2- chloromandelic acid.(R)-N-benzyl-1-phenylethylamine and (S)-2-chloromandelic acid.(S)-N-benzyl-1-phenylethylamine, separating one of the diastereomer salts and decomposing the separated salt. The amount of the component C is preferably 0.3-1.0 mol based on 1 mol of the component A.