Oxidative Cyclizations. V. The Oxidation of ortho-Substituted Benzenamines with Lead(IV) Tetraacetate

Abstract

Lead(IV) tetraacetate has been used to oxidize 1-aminoanthraquinone, 1-arylazonaphthalen-2-amines and benzenamines whose ortho-substitutents were arylazo, nitro, or benzopl. Only the amines with ortho-arylazo substituents underwent oxidative cyclization, to yield triazoles; the others yielded azo compounds and polymers. Experimental evidence shows that neither nitrenes nor arenamino ('anilenium') cations can be the reactive intermediates in some of these reactions. All the results can be rationalized in terms of the conjugate acid-base pair of intermediates, arenamine cation ArNH₂⁺' and arenamino ArNH.