Abstract
The reaction of methyl 2‐bromo‐6‐(trifluoromethyl)‐3‐pyridinecarboxylate (1) with methanesulfonamide gave methyl 2‐[(methylsulfonyl)amino]‐6‐(trifluoromethyl)‐3‐pyridine‐carboxylate (2). Alkylation of compound 2 with methyl iodide followed by cyclization of the resulting methyl 2‐[methyl(methylsulfonyl)amino]‐6‐(trifluoromethyl)‐3‐pyridinecarboxylate (3) yielded 1‐methyl‐7‐(trifluoromethyl)‐1__H__‐pyrido[2,3‐c][1,2]thiazin‐4(3__H__)‐one 2,2‐dioxide (4). The reaction of compound 4 with α,2,4‐trichlorotoluene, methyl bromopropionate, methyl iodide, 3‐trifluoromethylphenyl isocyanate, phenyl isocyanate and 2,4‐dichloro‐5‐(2‐propynyloxy)phenyl isothiocyanate gave, respectively, 4‐[(2,4‐dichlorophenyl)methoxy]‐1‐methyl‐7‐(trifluoromethyl)‐1__H__‐pyrido[2,3‐c][1,2]thiazine 2,2‐dioxide (5), methyl 2‐[[1‐methyl‐2,2‐dioxido‐7‐(trifluoromethyl)‐1__H__‐pyrido[2,3‐c][1,2]thiazin‐4‐yl]oxy]propanoate (6), 1,3,3‐trimethyl‐7‐(trifluoromethyl)‐1H‐pyrido[2,3‐c][1,2]thiazin‐4(3__H__)‐one 2,2‐dioxide (7), 4‐hydroxy‐1‐methyl‐7‐(trifluoromethyl)‐N‐[3‐(trifluoromethyl)phenyl]‐1__H__‐pyrido[2,3‐c][1,2]thiazine‐3‐carboxamide 2,2‐dioxide (8), 4‐hydroxy‐1‐methyl‐7‐(trifluoromethyl)‐N‐phenyl‐1__H__‐pyrido[2,3‐c][1,2]thiazine‐3‐carboxamide 2,2‐dioxide (9) and N‐[2,4‐dichloro‐5‐(2‐propynyloxy)phenyl]‐4‐hydroxy‐1‐methyl‐7‐(trifluoromethyl)‐1__H__‐pyrido[2,3‐c][1,2] thiazine‐3‐carboxamide 2,2‐dioxide (10).