Conjugate Addition of Alkyl Mercaptans and Thioacetic Acid to β-Chloro-α,β-didehydro-α-amino Acids: Studies toward the Synthesis of β,β-Bis(alkylthio)-α-amino Acids.

Article abstract of DOI:10.1021/jo01304a020

The conjugate addition of mercaptans to β-chloro-α,β-didehydroamino acids has been studied as a method for the preparation of β,β-bis(alkylthio)-α-amino acids.The addition of thioacetic acid was observed to yield β,β-bis(acetylthio)-DL-alanine derivatives.The addition of other mercaptans, such as benzyl mercaptan or appropriate cysteine derivatives, gave only the monosubstitution product, a β-(alkylthio)-α,β-didehydro-α-amino acid; addition of a second molecule of the mercaptan failed to occur.Studies were carried out on the addition of mercaptans to β, β-dichloro-α,β-didehydro-α-amino acid derivatives.By this method the unsymmetrical α,β-bis(alkylthio)dehydroamino acid 14 was prepared, though in low yield and of undetermined configuration.