K2CO3/TBAB, a Composite of Inorganic and Organic Salts, a Novel and Powerful Media for Regioselective Michael Addition of Dihydropyrimidinones to Acrylic Esters Under and Without Solvent Conditions

Aims: Synthesis of dihydropyrimidinones derivatives. Background: carrying out reactions in the green route and organic solvent-free conditions. Objective: Regioselective Michael addition of dihydropyrimidinones to acrylic esters. Methods: The reaction proceeded in the presence of K2CO3/TBAB, a media of inorganic base K2CO3 and organic ionic salt TBAB (tetrabutylammonium bromide) at 100°C. Results: A series of new dihydropyrimidinone derivatives using aza-Michael addition reaction were synthesized under solvent-free conditions. Conclusion: The reaction is characterized by high efficiency, relatively short reaction time, high yields, simple environmentally friendly reaction conditions. Other: The reaction of acrylic esters with dihydropyrimidinones produced N3-substituted derivative of dihydropyrimidinones with 85-95% yields in 6 h.