7-Chloro-5-trifluoromethyl/7-fluoro/7-trifluoromethyl-4H-1, 4-benzothiazines have been synthesized by 2-amino-5-fluoro/5-trifluoromethyl/5-chloro-3-trifluoromethyl benzenethiols condensed with β-diketone/β-ketoesters in the presence of DMSO involving oxidative