OPTICALLY ACTIVE 3,3'-DITHIOBIS(2-AMINO-2­METHYLPROPIONIC ACID) DERIVATIVE AND PROCESS FOR PRODUCING OPTICALLY ACTIVE 2-AMINO-3-MERCAPTO-2-METHYL­PROPIONIC ACID DERIVATIVE

摘要

A useful novel intermediate and a novel synthesis method which enable an optically active (R)- or (S)-2-amino-3-mercapto-2-methylpropionic acid derivative or a salt thereof which each is useful as an intermediate for medicines, etc. to be synthesized while highly inhibiting the inclusion of various impurities. A process is provided in which an optically active (R)- or (S)-2-amino-3-mercapto-2-methyl­propionic acid derivative or a salt thereof each having a high purity can be easily and efficiently produced on an industrial scale. The process, which is for producing a 2-amino-3-mercapto-2-methylpropionic acid derivative or a salt thereof each having a high purity, is characterized in that a high-purity, optically active 3,3'-dithiobis(2-amino-2­methylpropionic acid) derivative from which impurities have been removed is used as an intermediate and the sulfur-sulfur bond of this intermediate is reductively cleaved to convert the derivative into the corresponding optically active 2-amino-3-mercapto-2-methylpropionic acid derivative without generating by-product impurities difficult to remove.