Synthesis in the phenothiazine series

1,2-Dihydroimidazo4,5,1-n,m]phenothiazine-1-thione (III) was synthesized by the reaction of 1-aminophenothiazine (II) with sulfur and carbon disulfide or potassium ethylxanthogenate. The oxidation of III with hydrogen peroxide in alkali and acid media leads to imidazo-4,5,1-n,m]phenothiazine (I) and imidazo4,5,1-n,m]phenothiazine 6,6-dioxide (VI), respectively. Several S-alkyl and S-aralkyl derivatives of in (IVa-d) were obtained by the action of alkyl and aralkyl halides; the oxidation of IVa-d in acetic acid gave 1,2-dihydroimidazo-4,5,1-n,m]-1-phenothiazone 6,6-dioxide (VII).See 1] for communication XXXI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 770–772, June, 1971.