One-pot Synthesis of Novel Thiophene Containing Aminonaphthols using Fe3O4 Nanoparticles as a Recyclable Heterogeneous Catalyst

Background: Metal oxide itself and metal oxide nanoparticles are gaining significant importance due to their reusability and wide range of catalytic applications in many organic transformations. Objective: This study aimed to report a simple and efficient Fe3O4catalyzed one-pot fivecomponent reaction protocol for the synthesis of novel thiophene containing aminonaphthols under solvent-free conditions. Methods: To prepare the Fe3O4 nanoparticles by facile and simple co-precipitation method, surface characterization was done using FT-IR, XRD, BET, SEM, and TEM analysis techniques. Aminonaphthol derivatives bearing thiophene moiety were synthesized using Fe3O4 nanoparticles under solvent-free condition. Results: The prepared nanoparticles are smaller in size (15nm) and can be easily separated. They can be recycled and reused five times without any significant loss of catalytic activity with excellent yields in short time. The existing protocol for the synthesis of aminonaphthols becomes feasible and attractive due to reusability of catalyst, excellent catalytic performance, and eco-friendly procedure. Conclusion: In conclusion, Fe3O4 nanoparticles provide a simple, efficient and greener one-pot five component synthetic approach for the synthesis of thiophene containing aminonaphthols. Excellent catalytic activity was perceived in short reaction time without any co-catalyst or any other activator. Moreover, reusability of catalyst, high yields and environmentally benign solvent-free condition are key factors of this protocol.