Preparation of Optically Active-2-Thiazolidinecarboxylic Acid by Asymmetric Transformation

Abstract

Cysteamine was condensed with glyoxylic acid monohydrate in a mixture of acetic acid and ethanol in the presence of (2R, 3R)- or (2S, 3S)-tartaric acid [(R)- or (S)-TA], as the resolving agent, to give the salt of (-)-2-thia-zolidinecarboxylic acid [(-)-2-THC] with (R)-TA or the salt of (+)-2-THC with (S)-TA. Treatment of these salts with triethylamine in methanol afforded (-)- and (+)-2-THC. The (-)- and (+)-2-THC obtained were betermined to be enantiopure forms by comparing their powder X-ray diffiraction patterns with that of (RS)-2-THC. The absolute configurations of (-)- and (+)-2-THC were estimated based on molar rotations of (2R, 4R)- and (2S, 4S)-2, 4-thiazolidinedicarboxylic acids, (R)-4-thiazolidinecarboxylic acid, and (-)- and (+)-2-THC. (-)-2-THC was determined to have the (R)-configuration, and (+)-2-THC to have the (S)-configuration.