Biginelli Reaction of Vicinal Diols: A New Route for One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-One Derivatives

Background: 3,4-Dihydropyrimidin-2(1H)-one derivatives are an important class of nitrogen heterocycles. These compounds present a wide range of biological activities viz antibacterial, antifungal, and antidiabetic. Although many synthetic methods are available in the literature for the synthesis of these molecules, many of these methods have their own limitations such as use of excess of expensive catalyst and poor yields. Methods: The synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives is developed through the reaction of 1,2-diols, ethyl acetoacetate and urea in the presence of lead tetraacetate in dry ethanol under reflux conditions. Results: A series of 3,4-dihydropyrimidin-2(1H)-one derivatives were synthesized in good yields (82-95%) under reflux for 2-3.5 hours in ethanol solvent. The structural assignments of these compounds were made on the basis of elemental analysis and spectroscopic data. Conclusion: This protocol is an alternative to existing procedure for the synthesis of Biginelli compounds. The present methodology reduces the number of steps in total synthesis.