Two-step reduction of the O-methyloxime group in the antibiotic cefetamet

Most oximes as well as their N-alkyl and O-alkyl derivatives are electroche mically reduced in a single four-electron step to the amine. Some exception s have been reported, where the reduction occurs in two two-electron steps. The reduction of the O-methyloxime grouping in the antibiotic cefetamet oc curs at pH 5-9 in two steps, corresponding to a reduction to the imine and amine, respectively. It has been shown that the separation of the two two-e lectron processes is caused by differences in position and rate of establis hment of acid-base equilibria resulting in protonations of the oxime and im ino grouping. (C) 2001 Elsevier Science B.V. All rights reserved.