Catalysis in aromatic nucleophilic substitution. Part 1. Reactions of piperidine with 2,4-dinitrophenyl 4-nitrophenyl ether and 2,4-dinitrophenyl phenyl sulphone

Abstract

The rates of piperidino-substitution of 2,4-dinitrophenyl 4-nitrophenyl ether (1) and of 2,4-dinitrophenyl phenyl sulphone (2) in benzene at various piperidine concentrations and in the presence of some additives (dioxan, tetrahydrofuran, pyridine, acetonitrile, α-pyridone, methanol, and diazabicyclo [2.2.2]octane) indicate the possibility of catalytic decomposition of the reaction intermediate; e.g. clear evidence of catalysis has been obtained in the cases of piperidine and of α-pyridone. In other cases the additives seem to influence the reaction rates by affecting the nature of the solvent (tetrahydrofuran, pyridine, and acetonitrile) or giving rise to opposite, balancing effects (methanol). Dioxan does not affect the reactivity.