Efficient on-water synthesis of novel pyrano[3,2-e][1,2,4]triazolo[1,5-a]pyrimidines via catalyst-free one-pot three-component reaction

An efficient, catalyst-free and eco-friendly synthesis of novel pyrano[3,2-e][1,2,4]triazolo[1,5-a]pyrimidines via cyclo-condensation of [1,2,4]triazolo[1,5-a]pyrimidine-5,7(4H,6H)-dione, aromatic aldehydes, and malononitrile has been described using ‘‘On-water” concept. The use of water as a clean media, catalyst-free conditions, excellent functional group acceptance, easier product isolation/purification without column chromatography, short reaction times, and good-to-excellent yields are the remarkable privileges of this protocol. Finally, ¹H, ¹³C NMR, IR, mass spectra, and elemental analyses were conducted to determine the products’ structure.