Cyclization of Some 2,3,5,6-Tetrafluorophenylhydrazine Derivatives. Use of Nuclear Overhauser Effect Measurements in Structural Assignment

Abstract

Treatment of N-(2,3,5,6-tetrafluorophenyl)-N′-thiobenzoylhydrazine and of N-benzoyl-N′-(2,3,5,6-tetrafluorophenyl)hydrazine with acetic anhydride and triethylamine proceed without rearrangement to give 4-acetyl-2-phenyl-5,6,8-trifluoro-4H-1,3,4-benzthiadiazine and -benzoxadiazine, respectively. Structures follow from 19F n.m.r. and n.O.e. data.