Electrochemical Synthesis of 2-Aryl-2H-benzotriazoles and Their N-Oxides by Controlled Potential Cathodic Electrolysis

Using a divided cell, reductive cyclizations of o-nitrophenylazo dyes (1) toward 2aryl-2H-benzotriazole-1-oxides (2) or 2-aryl-2H-benzotriazoles (3) were successfully accomplished by the controlled potential cathodic electrolysis reactions.1 was transformed to 2 under neutral conditions while 1 was transformed to 3 under basic conditions.