Ultrasound assisted the green synthesis of 2-amino-4H-chromene derivatives catalyzed by Fe3O4-functionalized nanoparticles with chitosan as a novel and reusable magnetic catalyst

• Ultrasonic-assisted green synthesis of 2-amino-4H-chromene derivatives.
• The effect of frequency of ultrasound irradiation on the reaction was surveyed.
• With simple precursors Fe3O4–chitosan nanoparticles were prepared under ultrasound irradiation.
• Using magnetic nanocatalyst for improvement of yields than the reported methods.

Fe3O4 nanoparticles were prepared by chemical coprecipitation method. Subsequently immobilization of chitosan on Fe3O4 nanoparticles was accomplished and afforded magnetic Fe3O4-chitosan nanoparticles. Synthesized nanoparticles was found to be a magnetic and heterogeneous catalyst for a one-pot and efficient synthesis of 2-amino-4H-chromenes by condensation of aldehydes with malononitrile and resorcinol under ultrasound irradiation as an ecofriendly method. This convenient procedure allowed us to achieve products under ultrasound irradiation in short time and excellent yield without using of harmful catalyst. The present method will permit a further increase of the diversity within the 2-amino-4H-chromene family.