Ionic liquid-assisted synthesis of 2-amino-3-cyano-4H-chromenes: A sustainable overview

In advanced research, the role of ionic liquid is gradually enhanced as an alternative finding. For a long time, many strategies have been developed based on the ionic liquid conveying the role of greener solvents or catalysts. In the case of multi-component synthesis, ionic liquids have a wide range of applications to revise a method in a sustainable and greener approach. The last two decades have given a number of methods to achieve the 4H-chromene derivatives by applying different types of ionic liquids. Especially, 2-amino-3-cyano-4H-chromene moiety that exhibits pharmacological and biological activity, have been synthesized using simple or functionalized ionic liquids such as basic, acidic, neural, metal-tagged, or carbon-oriented ionic liquid. In this review, we have concised the multicomponent reactions that have been reported to synthesize the 4H-chromene derivatives following the versatility of ionic liquids.