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

Abstract

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).