Oxidation of aromatic amines by N-chloroanilides. Direction of polarity of the nitrogen–chlorine bond

Abstract

The effect of substituents in the aromatic ring as well as in the acyl moiety of some N-chloroanilides [XC₆H₄N(Cl)COR; X =m-Cl, p-Br, H, m-Me, p-Me; R = Me, Prⁱ, Et, PhCH₂, Ph] on the kinetics of oxidation of aniline and p-toluidine has been studied in 1 : 1 ethanol–water (v/v) at various temperatures. The reactivity decreases in the following order: m-Cl > p-Br > H > m-Me > p-Me; Ph > PhCH₂ > Me > Et > Prⁱ. For p- and m-substituted N-chloroacetanilides, a correlation with the Hammett σ parameter exists. On the other hand, the Taft equation gives an excellent fit with the rate data for five N-chloroacylanilides. The results are interpreted in terms of bimolecular interaction of the positive chlorine of the N–Cl bond and the amino nitrogen.