GO/MNPs-TEA-CuI in water: a green and efficient catalytic system for multicomponent preparation of highly substituted imidazoles and oxazoles.

A sustainable and highly efficient catalytic protocol has been developed employing graphene oxide-supported magnetic nanoparticles functionalized with triethanolamine and copper(I) iodide (GO/MNPs-TEA-CuI) for the synthesis of functionalized imidazole and oxazole derivatives. This magnetically recoverable catalyst promotes multicomponent coupling reactions between aryl aldehydes, aryl nitriles, and terminal alkynes in aqueous media under reflux conditions, emphasizing its environmentally benign nature. The system efficiently affords a broad scope of products in excellent yields (77%-99%) within short reaction times (15-80 min for imidazoles and 1-8 h for oxazoles). The catalyst exhibits outstanding activity, attributed to the synergistic interaction between the GO surface, magnetic core, and Cu(I) active centers, resulting in high TON and TOF values. Moreover, it tolerates diverse functional groups, including electron-donating, electron-withdrawing, and heteroaromatic substituents, enabling versatility in substrate design. The catalyst can be conveniently separated using an external magnet and reused for several consecutive cycles without appreciable loss of efficiency. Overall, this green and recyclable catalytic system offers an economical and scalable approach for constructing nitrogen- and oxygen-containing heterocycles, providing a promising route for sustainable synthesis in pharmaceutical and fine chemical industries.