Synthesis in the phenothiazine series
A new condensed system — imidazo[4,5,1-k,l]phenothiazine — was synthesized by the reaction of 1-aminophenothiazine with formic acid. The reaction of 1-aminophenothiazine with trifluoroacetic acid resulted in the formation of 1-trifluoromethylimidazo[4,5,1-k, l]phenothiazine. The cyclization of 1-acetamido- and 1-benzamidophenothiazines in the presence of hydrochloric acid gave 1-methyl- and 1-phenylimidazo[4,5,1-k, l]phenothiazines.