Synthesis of fluorophenothiazines via Smiles rearrangement and their conversion into sulfones

The synthesis of 3-fluoro-1-methylphenothiazines and 7-fluoro-9-methylnitro phenothiazines is reported. 3-Fluoro-1-methylphenothiazines have been prepa red by Smiles rearrangement of 5-fluoro-3-methyl-2-formamido-2-nitrodipheny l sulfides in alcoholic potassium hydroxide solution. The formyl derivative s were prepared by the formylation of resultant diphenyl sulfides obtained by the condensation of 2-amino-5-fluoro-3-methylbenzenethiol with o-halonit robenzenes in ethanolic sodium acetate solution. 7-Fluoro-9-methylnitrophen othiazines have been prepared by the condensation of 2-amino-5-fluoro-3-met hylbenzenethiol with o-halonitrobenzenes containing nitro group (sS) Or one nitro and halogen atom at both ortho positions to the reactive halogen ato m in ethanolic sodium hydroxide solution where Smiles rearrangement occurs in situ. Fluorinated sulfones have been synthesized by the oxidation of flu orinated phenothiazines by 30% hydrogen peroxide in glacial acetic acid, (C ) 1999 Elsevier Science S.A. All rights reserved.