Thermal Decarboxylation of Sulfur-Containing Amino Acids in the Presence of Acetophenone,a Preparation of 3-Methylthiopropylamine Hydrochloride

3-Methylthiopropylamine hydrochloride was prepared from d,l-methionine and acetophenone in 90~92% yield by heating. Methionine sulfone was decarboxylated to γ-aminopropylmethyl sulfone, which migrated at the same rate as the authentic sample obtained from 3-methylthiopropylamine by hydrogen peroxide treatment. S-Alkylcysteines (R = methyl, ethyl, n-propyl, n-butyl and n-amyl) were also decarboxylated to give a product which showed new spots of 2-alkylthioethylamine with higher R_F values than those of the corresponding amino acids.