Some features of the aminolysis of benzoyl chloride catalyzed by 4-dimethylaminopyridine in low-polarity aprotic media

The reaction of p-nitroaniline with benzoyl chloride in the presence of 4-dimethylaminopyridine leads to the formation of benzoyl-4-dimethylaminopyridinium chloride. The reactivity of this intermediate and the mechanism of the nucleophilic effect of the pyridinium base are due to the nature of the complexation in the intermediate. From the kinetic data and from the results of a study of the electric conductivity of benzoyl chloride-4-dimethylaminopyridine mixtures with various compositions it was concluded that dimers and larger homoassociates are formed, in addition to the hydrogen-bonded associates of the arylamine with the salt. The results demonstrate the presence of a multitude of associated forms in the intermediate product of nucleophilic catalysis in methylene chloride and other low-polarity aprotic media.