Phenothiazines. III

Synthesis of Phenothiazines by Smiles Rearrangement

Abstract

Preparation of phenothiazines from diphenyl sulfides by the Smiles rearrangement was examined. Heating of 4-chloro-2-acetamido-2′-nitro- and 4-chloro-2-nitro-2′-acetamidodiphenyl sulfide in quinoline effects deacetylation together with rearrangement and cyclization to form 2- and 3-chlorophenothiazines. 4, 4′-Dichloro-2-acetamido-2′-nitrodiphenyl sulfide affords 3, 7-dichlorophenothiazine by the usual method, in the presence of alkali hydroxide.