Efficient and Convenient Synthesis of N3-(Acyloxymethyl)dihydropyrimidinones by a One-Pot Two-Step Method

3,4-Dihydropyrimidinones modified with N3-(acetoxymethyl) and (aroyloxymethyl) groups can be regioselectively obtained in good yields by reactions of 3,4-dihydropyrimidinones with paraformaldehyde and substituted benzoic acids/acetic acid, by a one-pot two-step strategy in the presence of chlorotrimethylsilane. The advantages of this method are the simple procedure, the high regioselectivity of the products, shorter reaction time and the mild reaction conditions. Additionally, this method directly uses acid as acylation reagents and needs not acid anhydride or acyl chloride.