The Conjugate addition of mercaptans to P-chloro-a,@-didehydroamino acids has been studied as a method for the preparation of P, P-bis (alky1thio)-a-amino acids. The addition of thioacetic acid was observed to yield P, P-bis (acetylthio)-DL-alanine derivatives. The addition of other mercaptans, such as benzyl mercaptan or appropriate cysteine derivatives, gave only the monoeubititution product, a P-(alkylthio)-a, P-didehydro-a-amino acid; ...
