Preparation of 1λ4,2,4-benzothiadiazines from N-arylbenzamidines

Abstract

N-Arylbenzamidines react with sulphenyl chlorides and N-chlorosuccinimide to give the cyclic sulphimides, 1λ⁴,2,4-benzothiadiazines (7), as the major products. Two examples of the analogous 1λ⁴,2,4-benzoselenadiazine system (8) have been prepared by a similar route. When the ortho-positions of the N-aryl group are blocked, or when an arylsulphenamide is used in place of the sulphenyl chloride in the preparation, the open-chain sulphimides (1) are isolated, but 4,4′-thiobismorpholine gives 1-morpholino-1λ⁴,2,4-benzothiadiazines (2) as the major products.