N-Alkylation of Imidazoles with Dialkyl and Alkylene Carbonates

The reactions of imidazoles with a series of dialkyl and alkylene carbonates afforded the corresponding N-alkyl- and N-(hydroxyalkyl)imidazoles with high yields. The reactivity of dialkyl carbonates decreases in the series dimethyl > diethyl > dibutyl carbonate. Ethylene carbonate is a more efficient alkylating agent than trimethylene carbonate. The mechanisms of alkylation of imidazole with dimethyl carbonate and ethylene carbonate were studied by DFT quantum chemical calculations at the B3LYP/6-311++G(d,p) level of theory.