CHAPTER 6 - Cyclic Azomethine Imines from Diazenes (Azo Compounds)

Abstract

Publisher Summary Azomethine imines are generally represented, by two closed-shell resonance structures A↔B, both with charge separation.Specifically, structure A represents an iminium imide and structure B is essentially a diazeniumylide. This chapter describes the generation of 2-thioxo-2,4-dihydro-3 H -imidazol-1-ium-1-imides, as intermediates in the course of [3+2] cycloaddition reactions of azoalkenes and thiocyanic acid, resulting in the formation of 1-aminoimidazole-2-thione derivatives. It also describes some additional reactions of these heterocycle amines. The chapter further discusses the rhodium-catalyzed intramolecular interaction of ω -diazenyl α ′-diazo ketones, essentially, giving rise to the formation of two cyclic azomethine imine isomers, with an exocyclic terminal nitrogen atom, and with all three azomethine imine atoms embedded in the heterocyclic ring. It also describes the synthetic approaches to the starting materials, ω -diazenyl α ′-diazo ketones, and provides some [3+2] cycloaddition reactions of the cyclic azomethine imines prepared.