An expeditious synthesis of novel 3,4-dihydropyrimidin-2(1H)-one derivatives has been developed using a multi-component reaction involving the in situ generation of non-commercial β-ketoesters via transesterification of tert-butyl-β-ketoester with corresponding alcohol followed by the Biginelli reaction with arylaldehyde and urea in one-pot at 110 °C under green conditions.

In this study, we present the highly efficient and rapid synthesis of substituted dihydropyrimidinone derivatives through an ultrasound-accelerated approach. We utilize copper ferrite (CuFe₂O₄) magnetic nanoparticles as heterogeneous catalysts, employing the well-known Biginelli reaction, under solvent-free conditions. The impact of the solvent, catalyst amount, and catalyst type on the reaction performance is thoroughly investigated. Our method offers several notable advantages, including facile catalyst separation, catalyst reusability for up to three cycles with the minimal loss of activity, a straightforward procedure, mild reaction conditions, and impressive yields, ranging from 79% to 95%, within short reaction times of 20 to 40 min. Furthermore, in the context of fighting COVID-19, we explore the potential of substituted dihydropyrimidinone derivatives as inhibitors of three crucial SARS-CoV-2 proteins. These proteins, glycoproteins, and proteases play pivotal roles in the entry, replication, and spread of the virus. Peptides and antiviral drugs targeting these proteins hold great promise in the development of effective treatments. Through theoretical molecular docking studies, we compare the binding properties of the synthesized dihydropyrimidinone derivatives with the widely used hydroxychloroquine molecule as a reference. Our findings reveal that some of the tested molecules exhibit superior binding characteristics compared to hydroxychloroquine, while others demonstrate comparable results. These results highlight the potential of our synthesized derivatives as effective inhibitors in the fight against SARS-CoV-2.