Electroxidation of ortho-substituted aromatic amines mechanistic investigation

The anodic oxidation of ortho-substituted aromatic amines has been investigated at a platinum electrode in aprotic solvent by cyclic voltammetry and controlled potential coulometry. In neutral medium, the radical cation stemming from the electron transfer undergoes deprotonation and a head-to-head coupling reaction leading to a dimer, which evolves to the corresponding azoic compounds by further oxidation at the same potential. However, in the presence of tetrabutylammonium hydroxide, the radical cation generated undergoes a head-to-tail coupling with the substrate yielding a diamine. (C) 2004 Elsevier B.V. All rights reserved.