Synthesis of β-keto and α,β-unsaturated N-acetylcysteamine thioesters

Methods for the synthesis of N-acetylcysteamine thioesters of β-keto and α,β-unsaturated acids which avoid problems associated with methods requiring the intermediacy of the free acids are described, along with a convenient method for the removal of excess thiol from reaction mixtures using copper sulphate impregnated silica.