Reactions of (Aryl)(chloro)methyl p-Tolyl Sulfoxides with Tetrasulfur Tetranitride (S4N4): Formation and Characterization of 3,5-Diaryl-1,2,4,6-thiatriazine 1-Oxides

The reactions of (aryl)(chloro)methyl p-tolyl sulfoxides 2 with tetrasulfur tetranitride (S4N4) in p-dioxane at reflux gave 3,5-diaryl-1,2,4,6-thiatriazine 1-oxides, 3,5-diaryl-1,2,4-thiadiazoles, and 1-amino-3,5-diaryl-1,2,4,6-thiatriazine 1-oxides. For the first time, the structures of 3,5-diaryl-1,2,4,6-thiatriazine 1-oxides were unequivocally characterized based on X-ray crystallography of 3,5-di(3,4-dimethylphenyl)-1,2,4,6-thiatriazine 1-oxide. Treatment of the thiatriazine 1-oxides with m-CPBA gave 2,6-diaryl-4-(3-chlorophenyl)-1,3,5-triazines. Mechanisms are proposed for the formation of thiatriazine 1-oxides and 1,3,5-triazines.