FeTiO3 Catalyzed one-pot synthesis of tetrahydrobenzo[b]pyran derivatives

Multi-component metal oxides in comparison with simple metal oxides have the crystal structures and merits of tuning chemical compositions [1]. One of these multi-component metal oxides is FeTiO3 that show behavior antiferromagnetic and has a wide band gap (2.54 eV) [2]. FeTiO3 has potential applications in high temperature integrated circuits, spintronics, chemical catalysts, high power electronic devices and photocatalysts [2-4]. Benzopyrans and their derivatives have wide range of biologicaland and pharmacological properties such as diuretic, antisterility, spasmolytic, antianaphylactin and anticancer agents [5,6]. Also, this component can be used as cognitive enhancers for the therapy of neurodegenerative disease including Huntington’s disease, amyoprophic lateral sclerosis, alzheimer’s disease, Parkinson’s disease, Down’s syndrome and AIDS associated dementia [7]. In this work, a simple and efficient one-pot synthesis of tetrahydrobenzo[b]pyrans from the three-component reaction between dimedone, aldehydes, and malononitrile in the presence of FeTiO3 as a magnetic heterogeneous catalyst under microwave irradiation and solvent free conditions is described (scheme 1). The catalyst exhibits remarkable reactivity and is reusable. The final product was investigated by 1HNMR and 13CNMR spectroscopy. Advantageous features of this work including green, short reaction times, Simple work-up, easy, inexpensive and mild reaction conditions.