Substituent effects in synthesis of 4H-1,3,4-benzothiadiazines from hydrazonyl halides and thioacetate ion

Abstract

The reactions of a number of new hydrazonyl halides, mainly of the type PhCBr:N·NH·C₆H₃BrZ(2,4-), with potassium thioacetate in boiling acetonitrile have been examined. 4-Acetyl-2-phenyl-7-Z-4H-1,3,4-benzothiadiazines were isolated where Z = CN or CF₃, but apart from these and previously reported cases (Z = halogen), the synthesis seems not to be generally extendable to other substituents Z. Also described are 4-acetyl-2-phenyl-4H-1,3,4-benzothiadiazine (from PhCCl:NNHC₆H₄F-o) and 4-acetyl-9-bromo-2-phenyl-4H-naphtho[1,2-e][1,3,4]thiadiazine [from PhCBr:N·NH·C₁₀H₅Br₂(2,4-)].