Nano TiO2@KSF as a high-efficient catalyst for solvent-free synthesis of Biscoumarin derivatives

An efficient, simple and convenient route is described for the synthesis of biscoumarin (3,3'- (arylmethylene)bis(4-hydroxy-2h-chromen-2-one)) by using recyclable catalyst tio2@ksf. in this procedure, we synthesize a biscoumarin derivative via the three multi-component reactions (3mcrs) of two equivalent 4- hydroxycoumarin with one equivalent of various aromatic aldehydes in the presence of 20 mg nano tio2@ksf as homogeneous catalyst under solvent-free conditions at 100 °c for the convinced reaction times (8–15 min). the advantages of this protocol towards the synthesis of biscoumarin derivatives are: a) use of solvent-free conditions, b) inexpensive catalyst, c) using commercially available precursors, d) reusability of tio2@ksf up to four cycles without much loss in reactivity, e) simple work-up, f) high yields of pure products, g) short reaction times. the structure of all biscoumarin derivatives were confirmed by m.p., tlc, ft-ir, 1h nmr spectra and were compared with reliable references