A Highly Efficient and Solvent-Free Approach for the Synthesis of Quinolines and Fused Polycyclic Quinolines Catalyzed by Magnetite Nanoparticle-Supported Acidic Ionic Liquid

Abstract

Magnetite nanoparticle-supported ionic liquid (IL@Fe₃O₄) catalysts with varying anions were synthesized via step-wise functionalization of Fe₃O₄ nanoparticles. They were characterized through various analytical techniques like X-ray diffraction, transmission electron microscopy, thermal gravimetric analysis, Fourier-transform infrared spectroscopy, and energy-dispersive X-ray. Catalytic efficiency of the synthesized catalysts was evaluated through their utilization in the synthesis of biologically active substituted quinoline and fused polycyclic quinoline derivatives. The effect of varying anion on acidity of the catalyst was discussed and the mechanism has been proposed. The IL-1@Fe₃O₄ with acetate ion was found as a potential catalyst for the Friedlander reaction and gave excellent isolated yield of the targeted products under mild reaction condition. Facile catalyst separation through external magnet and its reusability up to six reaction cycles made the process environmentally benign.

Keywords:

• Friedlander reaction
• heterogeneous catalyst
• ionic liquid
• magnetic nanoparticles

Acknowledgments

Research facilities provided by Department of Chemistry, Sardar Patel University and P. D. Patel Institute of Applied Sciences, CHARUSAT is gratefully acknowledged. Authors thank CSMCRI, Bhavnagar and SICART, Vallabh Vidyanagar, for analysis at concessional rates.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

H.N.D. thanks UGC, New Delhi for fellowship under UGC BSR Scheme.