Triaminopyrimidine Based Porous Organic Polymers: Synthesis, Characterization and Catalytic Applications in One-pot Room Temperature Synthesis of Dihydropyranopyranes

Novel nitrogen-rich triaminopyrimidine based porous organic polymer (TAP-POP), was synthesized via a simple, cost-effective and catalyst-free Schiff base condensation between 2,4,6-triaminopyrimidine and terephthalaldehyde in N, N-dimethylformamide. The TAP-POP was characterized by FT-IR, Powder XRD, Solid-state C-13 and N-15 CP-TOSS NMR, TGA, BET, SEM and TEM analyses. This polymer containing lot of basic nitrogen sites, act as efficient heterogeneous base catalysts for the room temperature synthesis of dihydropyrano[3,2-c]chromenes and dihydropyrano[4,3-b]pyranes from aromatic aldehydes, malononitrile and 4-hydroxycoumarin/4-hydroxy-6-methyl-2H-pyran-2-one via a one-pot, three component reaction. This TAP-POP was easily recovered by simple filtration and was reused upto five times with only a marginal loss in its catalytic efficiency.