HALOGENO-O-PHENYLENEDIAMINES AND DERIVED HETEROCYCLES .I. REDUCTIVE FISSION OF BENZOTRIAZOLES TO O-PHENYLENEDIAMINES

4,5,6,7-Tetrachlorobenzotriazole and its 1-hydroxy-derivative have been reduced with zinc and hydrochloric acid to give 3,4,5,6-tetrachlpro-o- phenylenediamine (II ; R = Cl) in good yield. The corresponding diamines (II; R = Me or F) were obtained similarly from 4,5,7-trichloro-6-methyl(or fluoro)benzotriazole. Alternative syntheses of the tetrachloro- and methyltrichloro-phenylenediamines are described. Benzimidazoles, quinoxalines, and other heterocycles derived from the diamines, especially from tetrachloro-o-phenylenediamine, are reported.