Cetrimide-Based DES-Mediated Synthesis, Computational and Biological Studies of Quinoline-Appended Imidazo[1,2-a]pyridines

Abstract

Deep Eutectic Solvents (DESs) derived from Cetrimide and carboxylic acids have been developed as a sustainable medium for the synthesis of quinoline-appended imidazo[1,2-a]pyridines through cyclization and C(sp³)–H functionalization. This environmentally friendly strategy promotes high atom economy, eliminates use of toxic solvents, and supports sustainable synthesis with broad substrate tolerance. Subsequent formylation via the Vilsmeier–Haack reaction further enables selective modifications under the same green conditions. The synthesized products were thoroughly characterized by NMR, HR-MS, FTIR, and single-crystal X-ray analysis. The structural properties were also validated by DFT calculations, while biological evaluations revealed notable antibacterial, anticancer, and photophysical activities. The thermal properties, stability, and reusability of the DES system were confirmed through DSC and TGA analysis, reinforcing the method's green credentials and practical relevance in sustainable organic synthesis.