Substituted diphenylamines can be synthesized by Pd (0)-catalyzed N-arylation using o- nitroanilines and nitro-substituted aryl bromides for a substrate. Cyclization of the diphenylamines by various methods, including the intramolecular Pd (0)-catalyzed N- arylation, produces 2-methoxyphenazine which can easily be deprotected to give 2- hydroxyphenazine. This phenazine is required to synthesize methanophenazine, a novel ...