Cyclization reactions of 2-methylbenzenesulfonamides using N,N-dimethylcarbamoyl chloride, N,N-dimethyl-thiocarbamoyl chloride, and N,N-dimethylsulfamoyl chloride

Generation of C,N-dianions (2) of 2-methylbenzenesulfonamides (1) followed by addition of N,N-dimethylcarbamoyl chloride gave 2-(N,N-dimethylcarbamoyl )methylbenzenesulfonamides (3), which were cyclized to 3,4-dihydro-2H-1,2-b enzo[e]thiazin-3-one 1,1-dioxides (5). 3-Dimethylamino-2H-1,2-benzo)[e]thia zine. 1,1-dioxides (7) were obtained in one step by the reaction of 2 with N,N-dimethylthiocarbamoyl chloride. On the other hand, the reaction of 2 wi th N,N-dimethylsulfamoyl chloride yielded 2,2 ' -ethylene-bis(benzenesulfon amide)s (10) and / or 2,3-dihydro-1,2-benzothiazole 1,1-dioxides (11).