Synthesis of 3-bromo-1-methylphenothiazines by smiles rearrangement

Synthesis of 3-bromo-1-methyl phenothiazines is prepared by the Smiles rear rangement of 5-bromo-2-formamido-3-methyi-2'-nitro-4'-substituted diphenyl sulfides. The formyl derivatives were prepared by the formylation of the re sultant diphenyl sulfides obtained by the condensation of 2-amino-5-bromo-3 -methylbenzenethiol with o-halonitrobenzene in ethanolic acetate solution. However, halonitrobenzenes containing a nitro group at both ortho positions to the reactive halogen atom on condensation with 2-amino-5-bromo-3-methyl benzenethiol directly yielded 9-nitrophenothiazine as Smiles rearrangement and ring closure occur simultaneously in situ due to combined resonance and inductive effects reinforced by two nitro groups. The IR, NMR and Mass-spe ctral studies are also included.