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...