PRODUCTION OF OPTICALLY ACTIVE CARBOXYLIC ACID

摘要

PROBLEM TO BE SOLVED: To obtain an optically active carboxylic acid by optical resolution of the diastereomer salt from the corresponding racemic carboxylic acid by use of an optical resolution agent. SOLUTION: This optically active carboxylic acid is obtained by the following processes: (A) a racemic carboxylic acid is mixed with an optical resolution agent in an organic solvent followed by separation of the corresponding optically active carboxylic acid and the diastereomer salt of the optical resolution agent in the form of crystal by solid-liquid separation; (B) the optically antipodal, carboxylic acid and the optical resolution agent left in the organic solvent mother liquor after the solid-liquid separation are brought into contact with a chlorinating agent in the coexistence of an alcohol to separate and recover the optically antipodal carboxylic ester and optical resolution agent hydrochloride crystal from the optical resolution agent hydrochloride; (C) racemization and hydrolysis process where the optically antipodal carboxylic ester left in the mother liquor is recovered as racemic carboxylic acid; (D) the optical resolution agent is recovered as isolated state from the optical resolution agent hydrochloride; and (E) both the racemic carboxylic acid and optical resolution agent recovered is recycled to the optical resolution process A.