Synthesis and Bioassay of Dihydropyrano[3,2-b]chromenediones

Ytterbium perfluorooctanoate [Yb(PFO)(3)] is found to be an efficient catalyst for the microwave-irradiated synthesis of dihydropyrano[3,2-b]chromenediones by the one-pot condensation of kojic acid, aldehydes, and 1,3-dicarbonyl compound under solvent-free conditions. This approach offers many advantages, such as excellent product yields in short reaction time, solvent-free conditions, easy isolation of products, low catalyst loading, reusability of the catalyst, and the absence of volatile and hazardous emissions. The preliminary antimicrobial results of in vitro biological studies showed that most of the newly synthesized compounds display a moderate inhibitory activity against bacteria and fungi. The complete characterization of synthesized compounds and bioassay results are provided.