Heterocyclization of N‐(Chlorosulfonyl)imidoyl Chlorides with Anilines, a New Method of Synthesis of 1,2,4‐Benzothiadiazine 1,1‐Dioxides.

N-(Chlorosulfonyl)imidoyl chlorides react regioselectively with anilines, 2-aminomethylnaphthaline, or 1,2,3,4-tetrahydroquinoline leading to derivatives of 1,2,4-benzothiadiazine 1,1-dioxide. Heterocyclization occurs at the sterically less hindered C-6 atom in the case of 3-methoxy- and 3,4-dimethoxyaniline, while the reaction with 3-methylaniline leads to a mixture of cyclization products at the C-2 and C-6 atoms of aniline.