Reactions of 1-substituted 2,4-dinitrobenzenes with diamines and anilines : the question of base catalysis by amines

Abstract

Calculated second-order rate constants for the reactions of ethane-1,2- diamine and propane-1,3-diamine with 1-chloro-2,4-dinitrobenzene in methanol and with 2,4-dinitro-1-phenoxybenzene in dioxan/water (3 : 2) are mildly dependent on amine concentration. The catalysis is no weaker than that for monoamines and this is adduced as evidence suggesting that it does not represent base catalysis in the second stage of the intermediate-complex mechanism for activated aromatic nucleophilic substitution.     The aromatic amines m-anisidine, aniline, p-toluidine and p- anisidine mildly catalyse their own aminolysis reactions with 1-fluoro- 2,4-dinitrobenzene in methanol; the catalytic effects are not significantly smaller than that for the more strongly basic aliphatic amine butylamine. Contrary to an earlier report, there is no kinetic evidence to support charge-transfer complexing in the reaction of aniline with 1-fluoro-2,4-dinitrobenzene.