A practical route to azo compounds by metal-free aerobic oxidation of arylhydrazides using an NOx system

Abstract

Metal-free aerobic oxidation of arylhydrazides was developed for the environmentally friendly and practical synthesis of azo compounds. In the presence of NaNO₂, HNO₃, and O₂, various hydrazides including alkyl 2-arylhydrazinecarboxylates, 2-aryl-1-benzoylhydrazines, and symmetric hydrazines underwent aerobic oxidation to produce the corresponding azo compounds.