M. Ghiaci et R. Tabrizi, NOVEL METHODS FOR THE SYNTHESIS OF 3-ARYLMETHYL-4-THIAZOLIDINE CARBOXYLIC ACID-2-THIONES AND THEIR METHYL-ESTERS, Indian journal of chemistry. Sect. B: organic chemistry, including medical chemistry, 37(1), 1998, pp. 10-14
Reductive amination, using benzaldehyde derivatives and sodium borohyd
ride, on L-cystine yields N,N'-di (arylmethyl) cystines 7a-c which can
be converted into N,N'-di(arylmethyl) cystine dimethyl esters 8a-c by
esterification. The reductive reaction by zinc, hydrochloric acid and
methanol on the derivatives 7 and 8 yields the thiols 4a-c and 5a-c,
respectively which on reaction with CS2 or EtOCS2K are further convert
ed into 3-arylmethyl-4-thiazolidine carboxylic acid-2-thiones 1a-c and
their methyl esters 2a-c. Compounds 2a-c are also produced by esterif
ication of 1a-c. Fewer reaction steps and higher yields are the advant
ages of these methods.