One-pot pseudo-five-component synthesis of dihydropyrano[2,3-g] chromenes using sodium phthalimide/[BMIM]BF4 as high efficient catalytic system

Abstract

An efficient route for the synthesis of dihydropyrano[2,3-g] chromenes via one-pot pseudo-five component cyclization reaction of an aldehyde, malononitrile and 2,5-dihydroxy-1,4-benzoquinone in the presence of an effective and mild catalytic system containing sodium phthalimide and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF₄) ionic liquid (SPI/IL) was studied. The reaction products were characterized using ¹H NMR, ¹³C NMR, FTIR, Mass spectroscopy and elemental analysis. Environmentally eco-friendly catalyst, clean reaction with easy work-up (through simple filtration) and high yield products with no more purification are the main merits of this protocol. Presented method can be used for the synthesis of mentioned products (with pharmacology and Biologic properties) in large scales.