Polydepsipeptides. 13

Abstract
The synthesis of three collagen model analogs is described: Ac‐Ala‐Gly‐Pro‐Ala‐Gly‐Pro‐NHMe, Ac‐Ala‐Gly‐Pro‐Ala‐Glc‐Pro‐NHMe, and Ac‐Ala‐Glc‐Pro‐Ala‐Gly‐Pro‐NHMe, where Glc stands for glycolic acid. The 1H‐n.m.r. properties of these compounds in dimethylsulfoxide‐d6 and trifluoroethanol are described. While in DMSO‐d6 the compounds are random, in TFE the glycine amide protons seem to be less solvent exposed than the other amide protons. Little difference was found in the behavior of the three compounds.