Reactivity of pyridines and pyridine N-oxides toward benzoyl chloride in acetonitrile

The kinetics of hydrolysis of benzoyl chloride in acetonitrile at 25 degreesC, catalyzed by substituted pyridines and pyridine N-oxides, were studied by the conductometric method. A nucleophilic mechanism of the catalysis was proposed, and the rate constants for nucleophilic attack by the catalyst on the substrate were determined. The reactivity of pyridine N-oxides with respect to benzoyl chloride is higher by 3-6 orders of magnitude than the reactivity of pyridines with the same basicity. Differences in the reactivity of pyridines and pyridine N-oxides toward various electrophilic substrates are discussed.