PRODUCTION OF OPTICALLY ACTIVE AZETIDINE-2-CARBOXYLIC ACID

摘要

PROBLEM TO BE SOLVED: To obtain an optically active azetidine-2-carboxylic acid having high optical purity from an optical isomer mixture of an azetidine-2-carboxylic acid at one stage without using an expensive reagent for optical resolution. SOLUTION: In this method for obtaining an optically active azetidine-2- carboxylic acid by dissolving an optical isomer mixture of an azetidine-2- carboxylic acid of formula (1) (* is an asymmetric carbon atom) in a solvent and then cooling, the seed crystal of either of the optically active azetidine-2- carboxylic acids is added to the solution and the optical isomer is preferentially crystallized.