Cycloaddition in Synthesis of Sulfonamide Derivatives. III. : Convenient Synthesis of 3-Alkylthio-4H-1, 2, 4-benzothiadiazine 1, 1-Dioxides

Abstract

Synthesis of 3-alkylthio-4-methyl-4H-1, 2, 4-benzothiadiazine 1, 1-dioxides was conveniently achieved by [2+2] cycloaddition reaction of S-alkyl N-methyl-N-phenyldithiocarbamates with chlorosulfonyl isocyanate with subsequent loss of carbonyl sulfide, followed by cyclization of the resulting chlorosulfonyl isothioureas under Friedel-Crafts conditions.