Multicomponent Synthesis of Tetrahydrobenzo[b]Pyrans, Pyrano[2,3-d]Pyrimidines, and Dihydropyrano[3,2-c]Chromenes Catalyzed by Sodium Benzoate

Abstract

This study provides straightforward synthesis of 4H-pyran-annulated heterocycles that serve as drug-like candidates for biological purposes. It was found that these multicomponent reactions performed under green conditions in the presence of sodium benzoate as an efficient, environmentally benign, and commercially available organo-salt catalyst. The target 2-amino-4-aryl-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitriles, 7-amino-5-aryl-2,4-dioxo/(4-oxo-2-thioxo)-1,3,4,5-tetrahydro-2H-pyrano[2,3-d]pyrimidine-6-carbonitriles, and 2-amino-4-aryl-5-oxo-4,5-dihydropyrano[3,2-c]chromene-3-carbonitriles, which are estimated to be important in organic synthetic and medicinal chemistry, were obtained in high yields and relatively shorter reaction times through a simple filtration. The method is versatile and amenable to many substrates, as it requires no specialized devices such as microwave, ultrasound and ball-milling. The aim of the work is the synthesis of pyran-annulated compounds in the presence of sodium benzoate as the organo-catalyst. This procedure has several further advantages, such as isolation of heterocyclic products without column chromatography or other chromatographic methods, atom-economy, step-economy, and clean reaction profiles.

Keywords:

• Aryl aldehyde
• tetrahydrobenzo[b]pyran
• pyrano[2,3-d]pyrimidine
• green medium
• dihydropyrano[3,2-c]chromene
• sodium benzoate

Acknowledgements

The authors express our thankfulness to the Damghan University Research Council. The corresponding author would also like to thank Shahrekord University.

Disclosure statement

No potential conflict of interest was reported by the author(s).