Heterocyclic rearrangements. Part V. Rearrangement of 4-arylazo-and 4-nitroso-benzofuroxans: new syntheses of the benzotriazole and benzofurazan ring systems

Abstract

4-p-Anisylazo-5-nitrobenzofuroxan rearranges spontaneously to 2-p-anisyl-4,7-dinitrobenzotriazole, whose structure is proved by n.m.r. spectroscopy. 5-Dimethylamino-4-nitrosobenzofuroxan rearranges spontaneously to 4-dimethylamino-7-nitrobenzofurazan, whose structure was proved by independent synthesis. The preparation of some derivatives of 4-aminobenzofuroxan is reported.