General Synthesis Method of Hantzsch dihydropyridine Using Scrap Automobile Catalyst (SAC)

English (OpenAlex)

1,4-Dihydropyridine (DHP) derivatives are an important class of organic compounds known for their broad biological and pharmacological activities, particularly as calcium channel blockers, which make them valuable in medicinal chemistry. Given their significance, developing efficient and sustainable synthetic methods for these derivatives is crucial. In this study, we present a green, one-pot Hantzsch synthesis of 1,4-dihydropyridines using a Scrap Automobile Catalyst (SAC) as a sustainable and reusable heterogeneous catalyst. The multicomponent reaction was carried out under mild conditions using ammonium acetate in ethanol (EtOH) with various aldehydes and 1,3-diketones. The results demonstrate that the SAC-catalysed reaction proceeds efficiently, with electron-withdrawing substituents accelerating the reaction, achieving completion in just 1.5–2 hours. In contrast, reactions involving benzaldehyde required longer reaction times (up to 4 hours) but still afforded a high yield of 88%. This approach not only offers a rapid, high-yielding, and environmentally benign synthetic route but also provides an innovative solution for the valorisation of difficult-to-recycle automotive waste, aligning with the principles of green chemistry. The SAC catalyst proved to be reusable, further enhancing the sustainability of the process. This study highlights the potential of waste-derived catalysts in organic synthesis, offering a cost-effective and eco-friendly alternative to conventional method.