Cyclic voltammetry and controlled potential electrolysis of benzenesulfon-p-anisidide.

Anodic oxidation of benzenesulfon-p-anisidide (I) was investigated by cyclic voltammetry and controlled potential electrolysis at a glassy-carbon electrode in aqueous acetonitrile solution. I showed a single anodic wave below pH 7, and two anodic waves above pH 7.5. Electrolysis of I at pH 3.9 gave a coulometric n-value of two, and p-benzoquinone and benzenesulfonamide were obtained. Electrolysis of I at pH 10.5 and the potential of the first wave gave an n-value of about one, and N, N'-dibenzenesulfonyl-N-(4'-methoxy-phenyl)-5-methoxy-o-phenylenediamine (IV) was obtained. The formation of IV was interpreted in terms of a head-to-tail coupling of the free radical of I.