Ozonation of tertiary aromatic amines. Part I

Abstract

Dimethylaniline and its p-nitro-, p-chloro-, and p-methoxy-derivatives have been ozonised with ozone–oxygen or ozone–nitrogen in various solvents, at different temperatures and with different molar proportions of ozone to amine. We suggest that both radical and cationic intermediates result from attack at the nitrogen atom, leading to bis-(N-methylanilino)methyl peroxides and N-methylformanilides, together with other minor products, but no N-oxides. The mechanism is discussed and the results are compared with those of related reactions of dimethyl-aniline and with the results of ozonation of aliphatic tertiary amines. Cyclisation reactions with o-substituted dimethylanilines (o-NHAc and o-CO₂H) are reported and the ozonation of dimethylanilines is proposed as a synthetically useful method of demethylation.