DMF-dimethyl sulfate as a new reagent for the synthesis of β-lactams

A number of 2-azetidinones were synthesized in good to excellent yields by a novel reaction between Schiff bases, substituted acetic acids and alkoxymethylene-N,N-dimethyliminium salts, the adduct formed from DMF and O-alkylating agents. The advantages of this new method are mild reaction conditions, low cost, avoiding the use of chlorinating agents and easy purification of the products. The best results were obtained when DMF and dimethyl sulfate were used at room temperature.