Conformational aspects of polypeptides. XVII. Synthesis of oligomers and co‐oligomers derived from L‐alanine and L‐glutamic acid

A series of oligomers was synthesized of the form: Where Z is the benzyloxycarbonyl group and n = 2, 3, 5, 10. We encountered difficulty in dissolving the decamer in any solvent except strong organic acids. We therefore prepared co‐oligomers of the type: equation image where (a) w = x = y = 1; (b) w = 0, x = y = 3; and (c) w = x = y = 3. A series of model compounds composed of glycine L ‐alamine and γ‐methyl‐ L ‐glutamate were also prepared. We converted manyof the benzyloxycarbonyl oligopeptides into their corresponding acetyl derivatives. Some of these peptides were synthesized by mixed anhydride and active ester techniques while others were prepared via azide coupling techniques using the tert ‐butoxycarbonylhydrazide blocking group. All reactions proceeded with retention of configuration.