An Efficient Propylphosphonic Anhydride (T3P®)-Mediated MW-induced Solvent-free Rapid Synthesis of Enamino Esters and Ketones including 5,5- Dimethyl-3-aminocyclohex-2-enones

aims: This work presents a clean and convenient synthesis of various β-enaminones incuding 5,5-dimethyl-3-aminocyclohex-2-enones in good to excellent yields from the reaction of different primary amines with 1,3-dicarbonyl compounds by employing T3P® as a catalyst and performing the reaction under microwave irradiation and solvent-free conditions. background: This work presents a clean and convenient synthesis of various β-enaminones incuding 5,5-dimethyl-3-aminocyclohex-2-enones in good to excellent yields from the reaction of different primary amines with 1,3-dicarbonyl compounds by employing T3P® as a catalyst and performing the reaction under microwave irradiation and solvent-free conditions. This one-pot rapid reaction proceeded readily and tolerated a variety of functional groups. objective: A mixture of 2,5-pentandione, primary amine and T3P® (50% in AcOEt) was irradiated for appropriate time under microwave at 80 °C. method: A mixture of 2,5-pentandione, primary amine and T3P® (50% in AcOEt) was irradiated for appropriate time under microwave at 80 °C. After completing the reaction (TLC) and cooling to r.t., ethyl acetate and saturated aqueous NaHCO3 solution was added. The aqueous phase was extracted ethyl acetate. The combined organic layer washed with brine, dried over Na2SO4, filtered and solvent is removed under reduced pressure to afford the product, which recrystallized from diisopropyl ether. result: The presented results exhibit a better catalytic activity of T3P in the synthesis of enaminones. It can be concluded that T3P is the best catalyst as it took only a few minutes for completion of reaction with excellent yield of product that indicates T3P is more effective and more efficient compared to other catalysts. A comparison of efficiency of the present procedure with some of heterogeneous solid catalysts was evaluated as well. Clearly higher yield was established in this procedure compared to other catalysts. Furthermore, reaction of amines with dimedone were investigated as well, delivering excellent yields conclusion: The reaction catalyzed by T3P under microwave irradiation supplies a comprehensive method for the synthesis of enaminones. This work will find widespread application in the synthesis of these compounds. T3P is efficient and non-toxic, which makes the process economic, convenient, and benign. other: This work will find widespread application in the synthesis of these compounds. T3P is efficient and non-toxic, which makes the process economic, convenient, and benign.