Design, synthesis and in vitro evaluation of the antibacterial and antifungal activity of some new dihydropyrano[3,2-c]chromene derivatives

An efficient synthesis of some new dihydropyrano[3,2-c]chromene derivatives 4a-r by the cyclocondensation reaction of corresponding 2-thio(oxo)-1,2-dihydroquinoline-3-carbaldehyde - 1a-f, ethylcynoacetate 2a and 4-hydroxy-2H-chromen-2-one 3a-c using piperidine as a catalyst in refluxing ethanol via a MCRs approach was used. The structures of new compounds have been characterized on the basis of elemental analysis, FT-IR, 1H-NMR and 13C-NMR spectral data. Some of the synthesized compounds exhibit excellent antimicrobial activity.