Recent advances in magnetic nanocatalysts for synthesis of imidazo[1,2-a]pyridine frameworks

Abstract

Magnetic nanocatalysts (MNCs) have emerged as powerful and sustainable catalytic platforms for the synthesis of imidazo[1,2-a]pyridine derivatives, an important class of nitrogen-fused heterocycles with broad applications in medicinal chemistry, materials science, and agrochemistry. Their nanoscale dimensions, high surface area, and chemically tailorable surfaces provide enhanced catalytic activity, while their magnetic cores enable rapid and efficient recovery using an external magnet, eliminating the need for energy-intensive purification steps. Recent advances demonstrate that Fe₃O₄, CoFe₂O₄, γ-Fe₂O₃, and related magnetic nanomaterials—either alone or functionalized with metals, ligands, ionic liquids, or polymeric shells—can effectively promote classical condensations, Groebke–Blackburn–Bienaymé multicomponent reactions, Aldehyde–Amine–Alkyne coupling (A³-couplings), and oxidative cyclizations leading to diverse imidazo[1,2-a]pyridines under mild, green conditions. These catalysts often exhibit excellent stability, minimal metal leaching, and reusability across multiple cycles without significant loss of activity. Mechanistically, magnetic nanocatalysts facilitate carbonyl activation, imine formation, alkyne or isocyanide activation, and intramolecular cyclization, enabling high yields and broad substrate tolerance. Compared with conventional catalysts, they offer superior efficiency, selectivity, and environmental compatibility. This review summarizes key developments in magnetically recoverable catalytic systems for imidazo[1,2-a]pyridine synthesis and highlights their growing significance in advancing sustainable heterocyclic chemistry.