Triazine-based porous organic polymer: a novel heterogeneous basic organocatalyst for facile one-pot synthesis of 2-amino-4H-chromenes (original) (raw)
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Molecular Catalysis, 2019
Functionalized porous organic polymers are very demanding and promising material in heterogeneous catalysis due to their convenience in synthesis and versatility in framework composition. Further, owing to the tunable porosity, high specific surface area, ease of functionalization and chemical stability, this class of porous polymers have huge potential to be employed both as catalysis and catalyst support. Herein, we report N-rich triazinethiophene based microporous polymer TrzDBTH through the Friedel-Craft alkylation reaction of tripodal building block 2,4,6-tris[4-(bromomethyl)phenyl]-1,3,5-triazine with dibenzothiophene (DBTH) and used it as a heterogeneous base catalyst for one-pot synthesis of biologically important chromene derivatives. Further, sulfonation to this TrzDBTH material yielded sulfonated hyper-crosslinked porous polymer namely STrzDBTH, which can be used as solid acid catalyst for the synthesis of valuable chemical intermediate 5-hydroxymethylfurfural (HMF) from different biomass derived carbohydrates. As a base catalyst, TrzDBTH provides chromene yields from 88 to 93% and its sulfonated derivative STrzDBTH provides the HMF yields from 57 to 97% for different carbohydrate substrates. Both the materials displayed high recycling efficiencies for several catalytic cycles. Thus, these triazine-thiophene based porous organic polymers offer very economical, scalable and recyclable routes for the synthesis chromene derivatives and HMF.
Porous organic polymer bearing triazine and pyrene moieties as an efficient organocatalyst
Molecular Catalysis, 2020
Materials with high specific surface area and bearing abundant basic sites at their pore surface are very demanding as heterogeneous catalyst for the eco-friendly base catalyzed reactions. Here we have developed a new secondary amine linked triazine and pyrene containing microporous organic polymer (TrzPyPOP) through a simple polycondensation reaction between tetramine1,4-bis(4,6-diamino-s-triazin-2-yl)-benzene (SL-1) and monoaldehyde pyrene-1-carboxaldehyde. This new porous organic polymer TrzPyPOP is very rich in N-content with high BET surface area (1016 m 2 g − 1). High surface area and N-rich surface basic sites have been explored in its potential as heterogeneous organocatalyst for the synthesis of dihydropyrimidones via Biginelli condensation involving three-component coupling reaction. Only a very little amount of catalyst was effective for the synthesis of dihydropyrimidones derivatives (yields = 88-99 %) together with high recycling efficiency under the optimum reaction conditions.
Triazine-Based Porous Organic Polymers: Synthesis and Application in Dye Adsorption and Catalysis
Polymers
The scientific community has been developing promising materials to increase the sustainability and efficiency of production processes and pollutant environmental remediation strategies. Porous organic polymers (POPs) are of special interest, as they are insoluble custom-built materials at the molecular level, endowed with low densities and high stability, surface areas, and porosity. This paper describes the synthesis, characterization, and performance of three triazine-based POPs (T-POPs) in dye adsorption and Henry reaction catalysis. T-POPs were prepared by a polycondensation reaction between melamine and a dialdehyde (terephthalaldehyde (T-POP1) or isophthalaldehyde derivatives with a hydroxyl group (T-POP2) or both a hydroxyl and a carboxyl group (T-POP3)). The crosslinked and mesoporous polyaminal structures, with surface areas between 139.2 and 287.4 m2 g−1, positive charge, and high thermal stability, proved to be excellent methyl orange adsorbents, removing the anionic dye...
ChemCatChem, 2018
Incorporation of nitrogen functionality onto the high surface area porous polymeric network are very demanding in designing suitable heterogeneous organocatalyst having surface basicity. Here we report the synthesis of a new aminal-linked triazine based microporous organic polymer (TrzMOP) through a simple and efficient condensation pathway involving the reaction between 1,4bis(4,6-diamino-s-triazin-2-yl)-benzene (SL-1) and 2,5-thiophene dicarboxaldehyde. The material has been characterized by using powder XRD, FTIR spectroscopy, solid state magic-angle spinning 13 C NMR, CHN analysis, FESEM, CO2-TPD and N2 adsorption/desorption techniques. This nitrogen-rich new porous organic polymer showed very high catalytic efficiency for one-pot proficient synthesis of polyhydroquinoline derivatives via microwave assisted condensation reaction. As little as 8 mg of catalyst was found to be effective under the optimum reaction conditions. In addition, TrzMOP catalyzed synthesis of biologically active polyhydroquinoline derivatives are very cost effective, scalable, less time consuming, and environmentally benign compared to those of currently used as heterogeneous catalysts.
Advanced Materials, 2012
Microporous organic polymers (MOPs) are exciting materials for gas adsorption, chemical separations, and heterogeneous catalysis. [1] MOPs combine chemical stability with wide synthetic diversity. [2] A range of MOPs have been developed including polymers of intrinsic microporosity (PIMs), hypercrosslinked polymers (HCPs), porous aromatic frameworks (PAFs), conjugated microporous polymers (CMPs), and covalent organic frameworks (COFs). In 2008, Kuhn et al. reported the ionothermal synthesis of covalent triazine-based frameworks (CTFs). Using molten ZnCl 2 as both molten solvent and catalyst, cheap aromatic nitriles were trimerized at high temperatures (400-700 °C) to give triazine-based network polymers with high surface areas (apparent BET surface area of more than 3000 m 2 g -1 in some cases). CTFs have high thermal stability and CTF-1 and CTF-2 showed a limited degree of crystalline order. CTFs have been explored as sorbents for gas storage and organic dyes, [5b, 11] and their relatively low potential cost and avoidance of precious metal-catalyzed coupling chemistry make them appealing candidates for scale up. As an example of introducing functionality, 2,6-dicyanopyridine was trimerized to give an efficient, heterogeneous CTF solid catalyst for the selective, low-temperature oxidation of Submitted to 2 methane to methanol after coordination of platinum. Furthermore, CTFs have been used as solid supports for palladium nanoparticles in heterogeneous catalysis, significantly increasing the catalyst stability. [13] However, while the ionothermal method is efficient for triazine (C 3 N 3 ) ring formation in these CTFs, the high temperature and long reaction times required might limit practical applications.
Applied Organometallic Chemistry
A novel inorganic-organic hybrid, [Dy 4 (PDA) 4 (H 2 O) 11 (SiMo 12 O 40)]•7H 2 O denoted as (POM@Dy-PDA), based on a lanthanide cluster, a Keggin-type polyoxomolybdate, and PDA (1,10-phenanthroline-2,9-dicarboxylic acid) was prepared and fully characterized by elemental analysis, Fourier-transform infrared and UV-Vis spectroscopies, thermogravimetric analysis, powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction. The structural analysis study showed that the [SiMo 12 O 40 ] 4− ions reside in the interspace between two cationic layers as discrete counterions and are not coordinated to the rareearth ions. Significantly, this hybrid catalyst is a rare case of an inorganicorganic hybrid polyoxometalate (POM) with a PDA ligand based on CSD search (CSD version 5.40/November2018). The hybrid catalyst was further characterized via powder X-ray diffraction (PXRD) pattern at room temperature which indicated the good phase purity of the catalyst. BET and Langmuir surface area analysis indicate surface area of POM@Dy-PDA 6.6 and 51.3 m2g-1, respectively. The catalytic activity of the hybrid catalyst was successfully examined in the synthesis of 2-amino-4H-chromene derivatives through a multicomponent reaction. A three-component, one-pot reaction involving differently substituted benzaldehydes, resorcinol/α-naphthol/β-naphthol/ 4-hydroxycoumarin/3-methyl-4H-pyrazole-5(4H)-one, and malononitrile or ethyl cyanoacetate in the presence of a catalytic quantity of the aforementioned hybrid catalyst in EtOH/H 2 O under reflux condition gave the corresponding highly functionalized 2-amino-4H-chromenes in satisfactory yields. The catalyst can be reused several times without appreciable loss in its catalytic activity.
Porous Organic Polymers Containing Active Metal Centers as Catalysts for Synthetic Organic Chemistry
ACS Catalysis, 2018
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