β‐Cyclodextrin catalyzed access to fused 1,8‐dihydroimidazo[2,3‐b]indoles via one‐pot multicomponent cascade in aqueous ethanol: Supramolecular approach toward sustainability

An eco‐friendly multicomponent synthesis of substituted imidazole derivatives catalyzed by β‐cyclodextrin (β‐CD) was scrutinized for the first time via a one‐pot three‐compound reaction of aldehyde, isatin, and ammonium acetate in H2O–EtOH at 80°C. β‐CD is a supramolecule, highly efficient, biodegradable, and recyclable catalyst used to produce high yields of desired 1,8‐dihydroimidazo[2,3‐b]indoles. The developed protocol contains number of advantages like nontoxic, inexpensive catalyst; green reaction condition; easily available starting material; shorter reaction time; and good yields.