Mechanism of the reaction of 1,3-diaryltriazenes with tetracyanoethylene in the presence of acetic acid

Abstract

The mechanism for the reaction of 1,3-diaryltriazenes with tetracyanoethylene (TCNE) in the presence of acetic acid, giving Schiff's bases and arylhydrazonomalononitriles, has been investigated. The intermediacy of arylazomalononitriles was confirmed by crossover experiments using an arylamine different from the component of the triazene. The route to the azo compounds via TCNE–triazene adducts had already been established by a tracer experiment using an ¹⁵N-labelled triazene. However, the crossover experiments, as well as the result of the reaction of a triazene with the TCNE–2,6-dimethylaniline adduct, revealed an alternative route via TCNE–ArNH₂ adducts in the presence of acetic acid.