Cyclic Peptides with a Diversely Substituted Guanidine Bridge: Solid-Phase Synthesis and Structural Analysis

摘要

A solid solution! The solid-phase synthesis of original cyclic peptides containing a diversely substituted guanidine bridge is described (see scheme). The guanidine bridge is assumed to be able to adopt four different orientations inside the peptide cycle. NMR and modeling studies of Arg–Gly–Asp-related cyclic peptides showed that the degree of guanidine substitution (R1, R2=H, alkyl) can influence the bridge orientation and, therefore, the peptide conformation.