Studies on benzimidazoles. Part VII. Kinetics and mechanism of the reaction of thiophenoxydehalogenation of NN′-disubstituted 2-chlorobenzimidazolium perchlorates

Abstract

The kinetic behaviour of the title reaction was investigated as a function of pH, solvent and lithium perchlorate concentration. The results are mechanistically interpreted. The cleavage of the hydrogen–sulphur bond of the thiol and the formation of the linkage between sulphur and carbon in the position 2 of the benzoheterocyclic system are involved in the rate-determining step. The reactivity of the organic cation separated from its counterion is similar to that of the corresponding ion pair.