Dehydrooligopeptides. VII. Convenient Synthesis of Various Dehydrodi- and tripeptide Esters by Using <i>N</i>-Carboxy α-Dehydroamino Acid Anhydride

Abstract

Abstract The one-pot syntheses of N-protected Δ1- and Δ2-dehydrodipeptide esters by the coupling of N-carboxy α-dehydroamino acid anhydride (ΔNCA) with several kinds of C- or N-protected l-α-amino acids are described. In addition, it was found that a similar coupling of ΔNCA with both C- and N-protected α-amino acids also took place to give Δ2-dehydrotripeptide derivatives, involving eight kinds of important C-terminal segments of antrimycins and cirratiomycins. The configurational confirmation of the α-dehydroisoleucine residue of the antibiotics is also discussed.