Novel nitrogen-rich triaminopyrimidine based porous organic polymer (TAP-POP), was synthesized via a simple, cost-effective and catalyst-free Schiff base condensation between 2,4,6triaminopyrimidine and terephthalaldehyde in N, N-dimethylformamide. The TAP-POP was characterized by FT-IR, Powder XRD, Solid-state 13 C and 15 N 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-2one 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. cyclization (step 3) forms the pyrano[3,2-c]chromenes/pyrano [4,3-b]pyranes as the desired product. 2 3 4 5 6 7 8
A simple and efficient route for the synthesis of 1,8‐dioxodecahydroacridine derivatives in water is described using β‐cyclodextrin monosulphonic acid (prepared readily from β‐cyclodextrin obtained by enzymatic degradation of starch and chlorosulphonic acid), as an environmentally friendly acid catalyst. In this one‐pot method, 1,8‐dioxodecahydroacridine derivatives (19 compounds) are synthesized from dimedone, ammonium chloride and aromatic aldehydes in high yields (upto 94 %). All the synthesized compounds are extensively characterized by 1H and 13C‐NMR, ESI‐MS and also by their melting points. A plausible mechanism involving a multifunctional role for β‐cyclodextrin monosulphonic acid is proposed. The other key benefits and green credentials of this protocol are nitrogen assimilation (formation of organic nitrogen compounds from ammonium chloride in laboratory), use of water which is an environmentally benign solvent, solid acid catalyst, easy workup, reusability upto five times, milder reaction conditions and broad substrate scope.
An efficient and rapid approach for the synthesis of 1amidoalkyl-2-naphthols catalyzed by b-cyclodextrin-monosulphonic acid under solvent-free conditions is described. The catalyst can be prepared easily from readily available b-cyclodextrin in a single step procedure and is characterized by ESI-Mass (Electrospray Ionization-Mass), elemental analysis and TGA (Thermogravimetric analysis). Totally 29 compounds are prepared from various aromatic aldehydes, amides and 2-naphthol using this b-cyclodextrin-monosulphonic acid indicating the broad substrate scope of this method. The key benefits of this atom economical method comprise a simple and a single step preparation of the catalyst, shorter reaction time (6-20 minutes), good to excellent yields (72-96%), mild reaction conditions, wide range of functional group tolerance, absence of any tedious workup or purification, it avoids hazardous reagents/solvents and reusable upto five runs. A suitable reaction mechanism which is supported by energy minimization studies, is proposed.[a] N.
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