Synthesis of 1H-4,1,2-benzothiadiazines from substituted N-acetyl-N-aryl-N′-thioaroylhydrazines

Abstract

Treatment of N-acetyl-N-aryl-N′-thioaroylhydrazines, in which the N-aryl group is 2,4-disubstituted, with triethylamine in refluxing acetonitrile gives 6-substituted 1-acetyl-3-aryl-1H-4,1,2-benzothiadiazines in cases where the displaceable 2-substituent is bromine, fluorine, or iodine and the 4-substituent is electron-attracting; the synthesis fails when the 2-substituent is chlorine.