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 of recyclable catalyst TiO2@KSF. In this Method, we synthesis biscoumarin derivatives via 3multi-component reactions (3MCRs) of two equivalent 4-hydroxycoumarin with one equivalent of aromatic aldehydes using 20 mg nano TiO2@KSF as homogeneous catalyst under solvent-free conditions at 60 °C for the required reaction times (8–15 min). The advantages of this protocol in synthesis of biscoumarin derivatives as an solvent-free condition, using rather inexpensive catalyst, commercially available starting materials, reusability of TiO2@KSF, simple work-up due to solid phase, high yields and short reaction times. The catalyst can be recovered and reused for four times without much loss in reactivity. The structure of all biscoumarin derivatives was confirmed by FT-IR, 1H NMR spectra and compared with reliable references.