Synthesis of pyranocoumarins derivative by three-component coupling reaction of aryl glyoxals, malononitrile, and 4‑hydroxycoumarin catalysed by ZrO2 nanoparticles

Multicomponent reactions (MCRs) represent a very useful tool at the interface of the fields of organic synthesis and chemical biology due to their superior atom economy, convergent nature, and straightforward experimental procedures. In addition, they are valuable in the pharmaceutical industry for the construction of low molecular weight compounds[1]. Pyrano-fused coumarins (pyranocoumarins) are natural products that exhibit important biological properties, such as antifungal, insecticidal, anticancer, anti-HIV, anti-inflammatory, and antibacterial activities[2]. Recently, the application of nanoparticles (NPs) as catalysts has attracted worldwide attention because of their high catalytic activity and improved selectivity [3]. The surface of metal oxides, such as TiO2, Al2O3, ZnO, CuO and MgO, exhibits both Lewis acid and Lewis base character [4]. They are excellent adsorbents for a wide variety of organic compounds and increase the reactivity of the reactants. here we report the results of our studies on the reaction between 4‑hydroxycoumarin1 ,aryl glyoxals2 and malononitrile3 in the presence of ZrO2 nanoparticles as an efficient, and environmentally benign catalyst under solvent-free conditions to produces pyranocoumarins derivative4 in fairly good yield.