Studies on polypeptides. Part VII, : Synthesis of DL‐, L‐ and D‐2‐amino‐6‐dimethylamino‐4‐hexynoic acid

Abstract l‐ and D‐2‐amino‐6‐dimethylamino‐4‐hexynoic acid were synthesized, starting from L‐ and D‐propargylglycine obtained by enzymatic resolution of DL‐N‐ace‐tylpropargylglycine with acylase I. The dimethylaminomethylene group was introduced through a Mannich reaction of the N‐acetylpropargylglycine ethyl esters with formaldehyde and dimethylamine (Scheme A). By reaction of L‐ and D‐2‐amino‐6‐chloro‐4‐hexynoic acid, prepared by enzymatic resolution of the DL‐N‐acetyl compound, with dimethylamine identical end products were obtained, but in much lower yields (Scheme B).