Highly Efficient, Reusable, Functionalized Pyridinium Salts as a Catalyst for the Simple and Cost-effective Preparation of Tetrahydro [b] Benzopyran Derivatives

Background: In this work, a series of pyridinium-based ionic liquids (PBILs) were synthesized. Methods: Pyridinium-based ionic liquids (PBILs) were synthesized through a simple method, which were initially evaluated as catalysts for the synthesis of tetrahydro[b]benzopyran derivatives via a one-pot three-component reaction involving aldehydes, malononitrile, and dimedone. Results: The PBILs perform well in this condensation reaction, especially 1-methylpyridin-1-ium dimethyl phosphate (MPDMP). Conclusion: The advantages of this procedure are good yields, short reaction time, simplicity of implementation, and inexpensive starting materials.