[Ch][TAPSO] As an Efficient Ionic Liquid Catalyst for One‐Pot Synthesis ofTetrahydro‐4H‐chromenes and 3,4‐Dihydropyrano[c]chromenes

Abstract

Cholinium N‐Tris(hydroxymethyl)methyl‐3‐amino‐2‐hydroxypropanesulfonate [Ch][TAPSO] has been found as an efficient ionic liquid catalyst for the synthesis of tetrahydro‐4H‐chromenes and 3,4‐dihydropyrano[c]chromenes in water and EtOH : Water (3 : 2) respectively. [Ch][TAPSO] being a basic IL has also been observed to extract acidic compounds such as rhodamine B from IL‐ immiscible organic solvent such as acetone through acid‐base interaction. The extraction process of fluorescent dye rhodamine B was determined by ultraviolet‐visible (UV‐Vis) spectroscopy. The observed percentage extraction rate is 100 % upto 6 mM solution of rhodamine in acetone. This method results in faster reaction with operational simplicity and excellent yields of the products. Furthermore, the catalyst has a great capacity for reutilisation.