Three component, one-pot synthesis of dihydropyrano[3,2-c]chromene derivatives in the presence of H6P2W18O62 · 18H2O as a green and recyclable catalyst

The three-component one-pot synthesis of 2-amino-5-oxo-dihydropyrano[3,2-c]chromene derivatives by condensing 4-hydroxycoumarin, aldehydes and alkylnitriles using a catalytic amount of H6P2W18O62 · 18H2O in aqueous ethanol under heating conditions is reported.