A New Facile Ultrasound-Assisted Magnetic Nano-[CoFe2O4]-Catalyzed One-Pot Synthesis of Pyrano[2,3-c]pyrazoles

Pyrano[2,3- c ]pyrazole derivatives have been synthesized through a one-pot multicomponent condensation of various aldehydes, dialdehydes, and ketones with malononitrile, ethyl acetoacetate, hydrazine hydrate (or phenylhydrazine) in the presence of magnetic nano-[CoFe 2 O 4 ] catalyst under ultrasonic irradiation. The catalyst can be recovered using an external magnet and used repeatedly.