Serendipitous Discovery of Peptide Dialkyl Peroxides

In an attempt to synthesize a homologous series of peptide peresters, we investigated the reaction of the oxazol-5(4H)-ones of Pht-(Aib)(n)-OH (n=2-8) and tert-butyl hydroperoxide in the presence of 4(dimethylamino)pyridine. Unexpectedly, the major product isolated in each case proved to be the peptide dialkyl peroxide. This novel class of peptide derivatives was characterized by FT-IR, H-1-NMR, MS, cyclic voltammetry, and X-ray diffraction. On the basis of the experimental data, a plausible mechanism is proposed for this reaction.