1,2,3‐benzotriazines. II. Reactions of benzimidazo[1,2‐ c ][1,2,3]benzotriazines and naphth[1′,2′(2′,1′):4,5]imidazo[1,2‐ c ][1,2,3]benzotriazine

A number of methyl‐ and halogeno‐substituted benzimidazo[1,2‐c][1,2,3]benzotriazines were subjected to a series of hydrolytic cleavages in acid media. The reactions of these compounds with dilute sulfuric acid yielded 2‐( o ‐hydroxyphenyl)benzimidazoles. Concentrated hydrochloric acid produced a mixture of 2‐( o ‐chlorophenyl)‐ and 2‐( o ‐hydroxyphenyl)benzimidazoles. Hydrogen chloride in ethanol caused the formation of 2‐ phenylbenzimidazoles contaminated with small amounts of 2 ‐ ( o ‐chlorophenyl)benzimidazoles. The benzimidazo[1,2‐c][1,2,3]benzotriazines underwent the Sandmeyer reaction to form 2‐( o ‐chlorophenyl)‐ and 2‐( o ‐bromophenyl)benzimidazoles in excellent yields. These reactions illustrated the behavior of these 1,2,3‐triazines as internal diazonium compounds. Naphth[1′,2′(2′,1′):4,5]imidazo[1,2‐c][1,2,3]benzotriazine behaved similarly. Bromination of some benzimidazo[1, 2 ‐ c ][1,2,3]benzotriazines in aqueous medium yielded bromine‐substituted [1,2‐ c ][1,2,3]benzotriazines.