A novel synthesis of diareno-1,2-diazepines: intramolecular dehydrofluorination of 2,4,6-trimethylphenylazo-derivatives of fluoroaromatic compounds

Abstract

Formation of 1,2-diazepines via intramolecular elimination of hydrogen fluoride derived from methyl and fluorine substituents lying ortho to NN linkages occurs when the azo-compounds 2,4,6-Me₃C₆H₂NNC₆F₅, 2,4,6-Me₃C₆H₂NNC₆F₄CF₃-4, and 4-(2,4,6-Me₃C₆H₂NN)C₅F₄N are heated in organic solvents; for example, 2,3,5,6-tetrafluoro-4-(2,4,6-trimethylphenylazo)pyridine cyclizes to give 1,3,4-trifluoro-7,9-dimethyl-11H-pyrido[4,3-c]benzo[1,2]diazepine, the molecular parameters of which have been determined by X-ray crystallography.