Hydrobromic acid‐dimethyl sulfoxide reagent for dealkylation of 5,10‐dialkyl‐5,10‐dihydrophenazines: Synthesis of 10‐alkyl‐2(10H)‐phenazinones

Abstract By the reaction of 5,10‐dialkyl‐substituted 5,10‐dihydrophenazine with hydrobromic acid in dimethyl sulfoxide at 90–110°, 10‐alkyl‐2(10H)‐phenazinone was obtained as a major product. Brominated dihydrophenazine was isolated in the case of 1,6‐dichloro‐5,10‐dimethyl‐5,10‐dihydrophenazine.