Linear oligopeptides, 48. Synthesis, characterization and conformational analysis in solution of monodisperse protected homo‐oligomers derived from L‐norleucine

Abstract

AbstractA series of N‐ and C‐protected L‐norleucine homo‐oligomers from dimer to heptamer was prepared by the dicyclohexylcarbodiimide and acyl azide coupling methods. In the course of the synthetic approach tert‐butyloxycarbonyl as the N‐protecting and methoxy as the C‐protecting end groups were employed. The monodisperse oligomers synthesized in this manner were characterized and found to be chemically pure. A polarimetric investigation in a structure disrupting solvent also indicated that all reactions proceeded with complete retention of the configuration. By UV absorption and far‐UV CD it was shown that these peptides may exist in predominantly β‐form, statistical coil, or partially folded conformation depending upon molecular weight and nature of solvent.