Three-Component Process for the Synthesis of 4H-Pyrans Using a Recyclable Ionic Liquid in Aqueous Media

In the past decade, because of various therapeutic applications of 4H-pyrans in the pharmaceuticalindustry, the different synthetic protocols for their preparation have been reported [1-3]. In this study, the 4H-pyran derivatives were synthesized via three-component reaction ofdimedone or 4-hydroxycoumarin or ethyl acetoacetate with malononitrile and various aldehydeusing a basic ionic liquid in aqueous media (Fig. 1). 4H-Pyrans were produced in excellentyields and short times. From the viewpoint of greener chemical processes, combination ofrecyclable ionic liquid and water as a green co-solvent for the synthesis of 4H-pyrans makesthis ionic liquid an attractive and eco-friendly alternative solvent and catalyst.