Nano-kaolin/Ti(IV)/Fe3O4: a Natural Based Magnetic Nano-catalyst for the Synthesis of Coumarins

Nano-kaolin/Ti(IV)/Fe3O4 as an efficient natural based magnetic nano-catalyst was synthesized and characterized using commercial nano-kaoline. Structural properties of this catalyst were investigated by using various techniques such as fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), thermal gravimetric analysis (TGA) and energy-dispersive X-ray spectroscopy (EDX). Coumarines have shown various biological activities such as analgesic, antimicrobial, antimalarial, antioxidant, anti-inflammatory, anticancer, antituberculosis and anti-HIV properties. Nano-kaolin/Ti(IV)/Fe3O4 was used for the synthesis of coumarines via Pechmann condensation between phenols and β-ketoester under solvent-free conditions at 120 °C. In this procedure, we have used phloroglucinol, resorcinol, 1-naphthol, pyrogalol and chatechol as nucleophile and ethyl acetoacetate, ethyl 2-chloro-acetoacetate, ethyl propionylacetate, ethyl 3-oxo-hexanoate, 2-ethoxycarbonyl cyclopentanone and ethyl benzoylacetate as electrophile. The structure of coumarine products was identified by FTIR and NMR spectroscopies. This method offers has several advantages such as easy workup, short reaction times, high product yields and reusability of catalyst.