Nano-ZnO Impregnated on Starch—A Highly Efficient HeterogeneousBio-Based Catalyst for One-Pot Synthesis of Pyranopyrimidinone and Xanthene Derivativesas Potential Antibacterial Agents

A new method has been proposed for the synthesis of pyranopyrimidinone and xanthene derivatives using zinc oxide–starch nanocomposite as catalyst under microwave irradiation. The ZnO–starch nanocomposite was characterized by X-ray diffraction and scanning electron microscopy data, and the size of the ZnO-starch nanocomposite particles was estimated at 70–90 nm. The catalyst was used in the three-component condensation of aromatic aldehydes with barbituric acid and malononitrile and the 1:2 condensation of aromatic aldehydes with naphthalen-2-ol to obtain pyranopyrimidinone and xanthene derivatives, respectively. The catalyst can be reused several times without loss of catalytic activity. The proposed procedure utilizes affordable and inexpensive materials, provides excellent yields in short reaction time, and is eco-friendly, which makes it more economic than conventional methods. The antibacterial activity of the synthesized compounds was evaluated against M. luteus and P. aeruginosa.