An efficient and green method has been developed for the synthesis of kojic acid derivatives by employing 20 mol% β-cyclodextrin in aqueous media.
In a one-pot three-component reaction, an aromatic or aliphatic aldehyde, malononitrile and 5-hydroxy-2-hydroxymethyl-4H-pyran-4-one were condensed for the synthesis of 2-amino-8-oxo-4,8-dihydropyrano[3,2- b]pyran-3-carbonitrile derivatives in the presence of nano-silica sulfuric acid (SiO2–OSO3H nanoparticles) in improved yields. The catalyst is recoverable by simple filtration and can be used in the subsequent reactions.