Ultrasound-assisted nanoparticles catalyzed multicomponent reactions: recent progress in bioactive heterocycle synthesis

In light of growing concerns toward greener and more eco-friendly methods of organic synthesis, ultrasound-mediated nanocatalysis has emerged as a potent and robust technique in current organic chemistry, particularly for the preparation of heterocycles by means of multicomponent reactions (MCRs). The effect of ultrasonic irradiation via acoustic cavitation increases reaction rate, yield, and decreases energy input. In such circumstances, nanoparticles show increased catalytic efficiency because of improved mass transport and increased surface activity. This review offers a brief insight into recent trends in ultrasound-assisted nanoparticle-catalyzed MCRs for the synthesis of nitrogen- and oxygen-containing heterocycles in a green fashion. Particular attention will be paid to the significance of magnetic nanoparticles as catalysts for sustainable generation of various heterocyclic frameworks, namely, pyrazoles, chromenes, tetrazoles, triazoles, xanthenes, furans, imidazoles, indoles, pyridines, isooxazoles, pyrimidines, and acridines. This review discusses the latest trends in the modification of magnetic nanocatalysts reported during 2018–2026. Furthermore, a wide range of nanocatalysts–including metals, metal oxides, magnetic, and mixed nanomaterials–have been successfully employed under ultrasonic conditions to facilitate key organic transformations such as reduction, oxidation, condensation, C–C coupling, and cyclization, offering high yields, selectivity, and reusability.