Direct access to 5,6 dihydropyrido[2',1':2,3]/pyrido fused imidazo[4,5-c]quinolines via consecutive C-N and C-C bond formations in deep eutectic solvent under microwave irradiation

Deep eutectic solvents (DESs) are a novel class of ionic liquids that have recently gained considerable attention as a sustainable, non-toxic substitute of traditional organic solvent. Recent years have seen an increasing demand for DES system to synthesize various heterocyclic moieties. However, scaffolds containing polyheterocycles in their structural framework makes them a potential therapeutic agent. Herein, we have reported a tandem methodology for synthesizing rarely explored 5,6 dihydropyrido[2',1':2,3]imidazo[4,5-c]quinolines and pyrido[2',1':2,3]imidazo[4,5-c]quinolines in a choline chloride based DES medium under microwave irradiation. This sustainable approach offers a clean, straightforward synthetic strategy with mild reaction conditions and a wide range of desired compounds are afforded in excellent yields.