Solvent-free synthesis of 4-substituted coumarins using sulfonated magnetic-nanoparticle catalyst: A useful complement to the Pechmann reaction

Sulfonic acid supported carbon coated magnetic nanoparticles (Fe3O4@C@SO3H), was prepared by using low cost precursors and a facile immobilization technique. The final catalyst, which was characterized by FT -IR, vibrating, and SEM techniques, was found to be an efficient and environmentally benign solid acid for the Pechmann condensation of substituted phenols with ethyl acetoacetate leading to the formation of coumarin derivatives. This reaction was catalyzed by Fe3O4@C@SO3H under solvent-free condition at 120°C, to give the corresponding products in excellent yields. The catalyst is easily separated from the reaction condition and can be reused for several times with consistence in the activity. After the reaction, the catalyst could be effortlessly separated by external magnet. The catalytic system presented offers a useful strategy for the efficient synthesis of coumarin, simplicity in operation, and a green reaction profile by avoiding toxic conventional catalysts and solvents

کلیدواژه ها:

Heterogeneous catalyst ، Fe3O4@C@SO3H ، Coumarin ، Pechmann condensation ، Magnetic nanoparticles