High Catalytic Ability of Fe3O4/EDTA Magnetic Nanocatalyst in Comparison with Various Deep Eutectic Solvents for One-Pot Synthesis of 4H-Pyrans

In this work, various 3-cyano-4-aryl-4H-pyran derivatives were prepared efficiently through a one-pot, multicomponent synthesis between aromatic aldehyde, malononitrile and acetophenone derivatives or ethyl acetoacetate using Fe3O4/EDTA magnetic nanocatalyst and ethanol as solvent. The reactions were completed at room temperature in 10 min using 5 mg of catalyst and 2 mL of solvent to prepare 1 mmol of the product. The employed catalyst has consisted of magnetite nanoparticles core, which coated with EDTA to modify its surface and prevent the aggregation. In addition, the catalytic abilities of different deep eutectic solvents (DESs) such as choline chloride/tin (II) chloride, choline chloride/ zinc chloride and choline chloride/urea were compared with the nanomagnetic catalyst via this synthesis. The nanomagnetic catalyst showed higher ability in comparison with various DESs for the title reaction. The employed nanomagnetic catalyst has been recycled 4 times without important loss of its activity which shows its high efficiency and small leaching.