Crown ether complex cation ionic liquids: synthesis and catalytic applications for the synthesis of tetrahydro-4H-chromene and 1,4-dihydropyridine derivatives

ABSTRACT

A series of crown ether complex cation ionic liquids (CECILs) are synthesized by crown ethers chelated with sodium benzenesulfonates, and used as a green and environmental catalyst, for the synthesis of tetrahydro-4H-chromene and 1,4-dihydropyridine derivatives by three-component reactions of aromatic aldehydes and malononitrile with cyclic β-dicarbonyls or cyclic β-enaminoketones respectively, in H₂O/EtOH (1:1), at the reflux condition. CECILs, as a green and environmental catalyst, can be easily obtained and are stable. Furthermore, high conversions, short reaction times, and cleaner reaction profiles are some of the advantages of this method.

GRAPHICAL ABSTRACT

KEYWORDS:

• Crown ether complex cation ionic liquids
• crown ethers
• sodium benzenesulfonates
• tetrahydro-4H-chromene
• 1,4-dihydropyridine

Acknowledgements

The authors express their great appreciation to Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences for supporting this investigation.

Disclosure statement

No potential conflict of interest was reported by the authors.