Reactive intermediates. Part I. Synthesis and oxidation of 1- and 2-aminobenzotriazole

1-Aminobenzotriazole is prepared in four steps from o-nitroaniline (54%) and, directly, by the amination of benzotriazole with hydroxylamine-O-sulphonic acid. 2-Aminobenzotriazole is also formed in the latter reaction. Oxidation of 1-aminobenzotriazole with lead tetra-acetate, under very mild conditions, gives benzyne almost quantitatively which, in the absence of trapping agents, dimerises to biphenylene in unusually high yield. Trace amounts of triphenylene and 2-acetoxybiphenylene are also formed. Oxidation of 2-aminobenzotriazole with lead tetra-acetate or with iodobenzene diacetate gives cis,cis-mucononitrile in high yield.