Anodic oxidation of carboxamides. Part II. Anodic oxidation and pyridination of N-methyl-4′-methoxybenzanilide in acetonitrile

Abstract

Anodic oxidation of N-methyl-4′-methoxybenzanilide (N-methyl-MBA) was investigated by cyclic voltammetry end controlled potential electrolysis at a glassy-carbon electrode in acetonitrile- in the presence and absence of water or pyridine. In acetonitrile N-methyl-MBA showed a single anodic peak at 1.27 V versus the saturated calomel electrode with a peak height corresponding to that of a two-electron process. Added pyridine and/or water had no effect on the peak potential or peak height. On electrolysis of N-methyl-MBA in acetonitrile, p-benzoquinone, and N-methylbenzamide were mainly formed. Essentially the same results were obtained on electrolysis in the presence of added water. In the presence of excess of pyridine, electrolysis of N-methyl-MBA resulted in the formation of pyridinated N-methyl-MBA in which the pyridinium group was meta to the anilide nitrogen atom on the N-methylanisidine ring. The results were compared with those obtained on anodic oxidation of 4′-methoxybenzanilide.