Conformational Study of Structurally Constrained 18-Membered Cyclic Peptide Containing N,N′-Ethylene-Bridged-(S)-Phenylalanyl-(S)-Phenylalanine

Abstract

The conformation of cyclo[(2S,3′S)-2-(3′-benzyl-2′-oxopiperazin-1′-yl)-3-phenyl-propanoyl-glycyl]₂ crystallized with two water molecules (C₄₄H₄₆N₆O₆ 2H₂O) is compared with its solution structure and those of cyclo[(2S, 3′S)-2-(3′-methyl-2′-oxopiperazin-1′-yl)-propanoyl-glycyl]₂.