Unusual reaction of 1,4-diamino-2-nitrobenzene derivatives toward nucleophiles: Catalysis by sodium sulphite

Abstract

Unusual substitution of amino group occurs by reactions of some 1,4-diamino-2-nitrobenzenes (semipermanent hair dyes) and nucleophiles (NH 3, H 2O). The reaction is catalyzed by sodium sulfite. The obtained products are suspected of being toxic substances which may be present in cosmetic matrices. Apparently, this reaction is a nucleophilic aromatic substitution but it may be explained by a mechanism involving a tautomeric form of substrate.