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

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.

Automated summary

This study presents a straightforward synthesis method for 4H-pyran-annulated heterocycles, which are potential drug candidates. By utilizing sodium benzoate as the catalyst under green conditions, the multicomponent reactions achieved high yields and shorter reaction times. The method is versatile, requiring no specialized devices, and offers additional advantages.