Synthesis of 1-methyl-3,7-disubstituted phenothiazines

Synthesis of title compounds by the Smiles rearrangement has been reported. 1-Methyl-3,7-disubstituted phenothiazines have been prepared by the: Smile s rearrangement of 2-formamido-3-methyl-2'-nitro-5,4'-disubstituted disulid es. The latter were obtained by the condensation of 2-amino-3-methyl-5-subs tituted benzenethiols with o-halonitrobenzenes. However, halonitrobenzenes containing a nitro group at both ortho positions to the reactive halogen at om on condensation with 2-amino-3-methyl-5-substituted benzenethiols direct ly yielded 9-nitrophenothiazines as Smiles rearrangement and ring closure o ccurs in situ due to combined resonance and inductive effects reinforced by two nitro groups. The IR, NMR and Mass-spectral studies are also included.