Ionic Liquid: A Review on Multicomponent Synthesis of Dihydropyrano [3,2-c] Chromenes

The development of efficient and eco-friendly synthetic processes or techniques for the synthesis of heterocyclic compounds is increasing enormously. Here, an environmentally friendly ionic liquid is used as an efficient catalyst for the synthesis of biologically important dihydropyrano [3,2- c] chromenes. This is because ionic liquids play an important role in green chemistry due to their distinctive properties, easy handling, non-toxicity, increased reaction selectivity, and low solubility. This review focuses on dihydropyrano [3,2-c] chromenes synthesis due to their great importance as natural products, pharmaceuticals, and bioactive molecules. The review summarizes the application of ionic liquids as an effective catalyst for the multicomponent synthesis of dihydropyrano [3,2-c] chromene derivatives by using aromatic aldehydes, 4-hydroxycoumarin, and malononitrile in a green chemical manner.