Aromatic nucleophilic substitution reactions of some 2-L-3-nitro-5-X-thiophenes with piperidine and aniline in methanol. Substituent constants for the thiophene system

Abstract

The rate constants for the reactions of some 2-L-3-nitro-5-X-thiophenes 1–4 with aniline and of compounds (4) with piperidine in methanol have been measured at various temperatures. By using the data obtained in this work as well as previously available data sets, a series of optimized ‘thiophene’σ_T values has been calculated. The susceptibility constants ρ(L)of the various sets have been analysed in the framework of the reactivity–selectivity principle.