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 beta-cyclodextrin (beta-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 degrees C. beta-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.