Studies on benzimidazoles. Part VI. Reactivity of some NN′-disubstituted 2-chlorobenzimidazolium perchlorates with thiophenol

Abstract

The reactivity of several 2-chloro-N-methyl- and 2-chloro-NN′-dimethyl-benzimidazolium perchlorates with thiophenol in acidic medium has been kinetically investigated. The effect on reactivity of structural changes in benzimidazole and in thiophenol has been correlated by the use of Hammett-type equations. The reactivity of 2-chloro-NN′-dimethylbenzimidazolium perchlorates is affected by substitution in benzimidazole more than has been observed for the corresponding protonated N-methyl derivatives. On the other hand NN′-dimethylbenzimidazoles react more quickly with thiophenol than the protonated benzimidazoles. The overall results are discussed on the basis of solvation effects.