Nano TiO۲@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 (۳,۳'-(arylmethylene) bis (۴-hydroxy-۲H-chromen-۲-one)) by using of recyclable catalyst TiO۲@KSF. In this Method, we synthesis biscoumarin derivatives via ۳multi-component reactions (۳MCRs) of two equivalent ۴-hydroxycoumarin with one equivalent of aromatic aldehydes using ۲۰ mg nano TiO۲@KSF as homogeneous catalyst under solvent-free conditions at ۶۰ °C for the required reaction times (۸–۱۵ 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 TiO۲@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, ۱H NMR spectra and compared with reliable references.

Keywords:

Aromatic Aldehydes , Biscoumarins , Nano TiO۲@KSF , Solvent-free conditions , ۴-Hydroxycoumarin