Barium salts of dibenzylidene cystines 8a-c were obtained from the reaction of Lcystine
with benzaldehyde or its derivatives in the presence of barium hydroxide.
Their reduction with zinc and hydrochloric acid in methanol yielded the Narylmethylcysteines
?9a-c?. These can, in turn, be converted by esterification into the
methyl esters ?10 a-c. ?Reaction of N, N'-carbonyl diimidazole (Im CO) or N, N'-
thiocarbonyl diimidazole (Im Cs) with thiols 9a-c and 10a-c gave 3-arylmethy-4-
thiazolidine-carboxylic acid-2-ones 3a-c or 2-thiones la-c and their methyl esters 4ac
and 2a-c respectively. From the reaction of P S with 3-arylmethyl 4 thiazolidine
crespectively acid-2-ones 3a-c and 4a-c the derivatives of 2-thiones 2a-c and la-c were
obtained as well