Anodic Oxidation of N,N,N'-Triphenyl-o-Phenylenediamine

The anodic oxidation of N,N,N'‐triphenyl‐ o ‐phenylenediamine in acetonitrile at platinum leads to 5,10‐dihydro‐5,10‐diphenylphenazine in near quantitative yields via an intramolecular cyclization reaction. This reaction is the key intermediate step in the formation of dihydrophenazines from substituted diphenylamines. Selection rules are presented for these reactions defining the structural requirements and electrolysis conditions necessary.