Conformational flexibility of peptides containing α,β‐unsaturated amino acid residues. I. Conformational analysis of N‐acetyl‐N′‐methylamides of dehydroalanine and N‐methyldehydroalanine

Conformational energy calculations on the N‐acetyl‐N′‐methylamides of dehydroalanine and N‐methyldehydroalanine indicate that their conformational behavior is very different from that of the corresponding saturated compounds. The conformational data in the literature from x‐ray and nmr investigations on peptides containing α,β‐unsaturated residues are discussed on the basis of these theoretical results.