Ion exchange resins as recyclable and heterogeneous solid acid catalysts for the Biginelli condensation: An improved protocol for the synthesis of 3,4-dihydropyrimidin-2-ones

Silty Clay-Containing Soil Catalyzed Microwave Assisted Multicomponent Synthesis of Octahydroquinazolinone Derivatives

“…1 Octahydroquinazolinone have been synthesized using aromatic aldehydes, dimedone and urea/thiourea in presence of various catalysts such as montmorillonite, 7 zeolites, 8 boron compounds, 9 Zn(OTf)2, 3 conc. H2SO4, 10 ionic liquids, 11 ion exchange resins, 12 Trimethyl silyl chloride, 13 Nafion-H, 14 VOSO4, 15 conc. HCl, 16 Fe(NO3).9H2O, 17 silica sulfuric acid, 18 t-BuOK, 19 TiO2, 20 ammonium metavanadate, 21 Cu(OTf)2, 22 phosphotungstic acid nanoclusters, 23 BMI.InCl4, 24 SiO2-NaHSO4, 25 ZnO2 nanoparticles, 26 phytic acid, 27 lanthanum oxide, 28 Naion-Ga, 29 CuS QDs, 30 ZrOCl2.8H2O, 31 Cu/SiO2, 32 β-cyclodextrin, aqueous hydrotropic solution of Na-p-Toluene sulfonic acid under microwave irradiation (MW), 33 BF3.SiO2, 34 Aluminate Sulfonic Acid Nanoparticles, 35 Ion exchange resin Nafion 12 H4CuPW11O39, 36 polyvinyl polyvinylpolypyrrolidine supported chlorosulfonic acid, 37 and molybdenum based heterogeneous catalysts (MoO2(acac)2 on zeolite) 38 under MW irradiation.…”

Valorization of Different Wastes and Their Use for the Design of Multifunctional Eco-catalysts

“…Some of these methods use homogeneous catalysis, such as ZrCl 4 [34], SbCl 3 [35] and various HPAs such as H 4 PMo 11 VO 40 [36], H 3 PMo 12 O 40 [37]. For heterogeneous catalysis, ionic exchange resins [38], different ionic liquids [39], supported heteropolyacids [40] and zeolites [41] have been studied. Finally, several catalysts, in solvent-free conditions, have been investigated: Y(NO 3 ) 3 Á6H 2 O [42], chloroacetic acid [43], KAl(SO 4 ) 2 Á12H 2 O supported on silica gel [44], TaBr 5 [45], and alumina-supported MoO 3 [46].…”

Titanium dioxide supported on MWCNTs as an eco-friendly catalyst in the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones accelerated under microwave irradiation

“…16 3,4-DHPM scaffolds have been also suggested as valuable building blocks to synthesize versatile heterocyclic derivatives. [17][18][19] Due to the importance of the Biginelli reaction products (DHPMs), numerous modifications and improvements have been developed to perform the Biginelli reaction with different types of catalysts such as ionic liquids, 20 phase-transfer catalysis, 21 Brønsted acids, 22 Brønsted bases, 23 Lewis acids, 24 heterogeneous catalysts, 25 ion-exchange resins, 26 polymer supported catalysts 27,28 and solid phase reagents, 29,30 and various conditions such as solvent-free, 31 ultrasound, 32 microwave synthesis, 33 green approach synthesis 34 and the grindstone technique. 35 The replacement of conventional toxic and polluting reagents with environmentally benign and reusable catalysts and using cleaner, safer and eco-friendly technologies are an active area of research.…”