SYNTHESIS OF 5,6-DICHLORO-3-METHYL-4H-1,4-BENZOTHIAZINES AND 5,7-DICHLORO-3-METHYL-4H-1,4-BENZOTHIAZINES AND THEIR CONVERSION INTO SULFONES

A one pot synthesis of 5,6- and 5,7-dichloro-3-methyl-4H-1,4-benzothia zines is reported by the condensation and oxidative cyclization of 2-a mino-3,4- and 3,5-dichlorobenzenethiols with beta-dicarbonyl compounds . The oxidation of 4H-1,4-benzothiazines by 30% hydrogen peroxide in g lacial acetic acid has provided the corresponding sulfones. The effect of the conversion of the sulfide linkage to sulfone is discussed. The structure of all the newly synthesized compounds has been confirmed b y elemental analysis and spectral studies.