Magnetically Nanoparticles of Antimony-Modified Nickel Ferrite: An Efficient Catalyst for Synthesis of Biscoumarins from 4-Hydroxycoumarin and Aromatic Aldehydes

4-Hydroxycoumarin and its derivatives are known for their anticoagulant [1], spasmolytic [2], antibacterial, and antifungal activities [3]. In addition, certain derivatives have also been reported as antitumor and anti-HIV agents. Besides, coumarins find diverse applications as agrochemicals. Bis (4-hydroxycoumarin-3-yl) methanes are obtained by the condensation of two molecules of 4-hydroxycoumarin with one reusable catalyst. This subject prompted us to prepare NiFe2O4/Sb as an efficient nanocatalyst toward synthesis of bis-coumarins with 4-hydroxycoumarin and aromatic aldehydes in ethylene glycol (Scheme 1). High activity and easy separation makes NiFe2O4/Sb as an ideal catalyst for this transformation. The procedure has the advantages of mild reaction conditions, high yields of products, short reaction time, and simple experimental technique, making it a useful and attractive process.