DEMETHYLATION AND AUTO-OXIDATION OF DIFFERENT COBALT-BLEOMYCIN COMPLEXES

Abstract

Demethylation of Co-bleomycin A₂ by heating yields three different complexes: form I and form II and "orange" Co-bleomycin-demethyl A₂. These complexes can be separated by HPLC and show different 1H NMR spectra. Preparation of Co-bleomycin-demethyl A₂by chelation of bleomycin-demethyl A₂ with cobalt yields a Co-bleomycin-demethyl A₂, which is auto-oxidized into Co-bleomycin A₁.