A magnetic nanoparticle supported dual acidic ionic liquid: a “quasi-homogeneous” catalyst for the one-pot synthesis of benzoxanthenes

Abstract

A novel magnetic nanoparticle supported dual acidic ionic liquid catalyst was synthesized by anchoring 3-sulfobutyl-1-(3-propyltriethoxysilane) imidazolium hydrogen sulfate onto the surface of silica-coated Fe 3 O 4 nanoparticles. Due to the combination of nano-support features and flexible imidazolium linkers, it acted as a "quasi-homogeneous" catalyst to effectively catalyze the one-pot synthesis of benzoxanthenes by a three-component condensation of dimedone with aldehyde and 2-naphthol under solvent-free conditions. More importantly, the catalyst could be easily recovered by an external magnet and reused six times without significant loss of catalytic activity.

Synthesis and Characterization of Fe3O4@SiO2 NPs as an Effective Catalyst for the Synthesis of Tetrahydrobenzo[a]xanthen-11-ones

“…The nanostructures involving silica-coated magnetite nanoparticles (Fe 3 O 4 @SiO 2 core-shell nanoparticles) as catalyst with many reactive portions, acidic features and high surface area do not only supply high chemical stability but are also appropriate for the many functionalizations. 6,7 Recently, functionalized magnetite nanoparticles were used as efficient catalytic systems in many chemical transformations including synthesis of α-amino nitriles, 8 1,1-diacetates from aldehydes, 9 diazepine derivatives, 10 indazolo[2,1-b]phthalazine-triones and pyrazolo [1,2-b]phthalazine-diones, 11 3,4-dihydropyrimidin-2(1H)-ones, 12 2-amino-4H-chromen-4-yl phosphonates, 13 1,4-dihydropyridines 14 and pyrrole synthesis. 15 In addition, a series of organic reactions such as Knoevenagel condensation/Michael addition, 16 Suzuki/Heck cross-coupling, 17 asymmetric aldol reaction, 18 Suzuki coupling, 19 asymmetric hydrogenation of aromatic ketones, 20 acetalization reaction, 21 Ritter reaction, 22 23 Henry reaction, 24 enantioselective directaddition of terminal alkynes to imines 25 have been done using functionalized nanostructures.…”

Facile One-Pot Synthesis of Amidoalkyl Naphthols and Benzopyrans Using Magnetic Nanoparticle-Supported Acidic Ionic Liquid as a Highly Efficient and Reusable Catalyst

“…In our previous work [38], the AIL@MNP was prepared by anchoring 3-sulfobutyl-1-(3-propyltriethoxysilane) imidazolium hydrogen sulfate onto the surface of silica-coated Fe3O4 nanoparticle (Scheme 2) and well characterized by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), elemental analysis (EA), thermogravimetric analysis (TG) and vibrating sample magnetometer (VSM). The AIL@MNP were spherical shapes with approximately 25 nm diameters.…”

“…On the other hand, magnetic nanoparticles (MNPs) have appeared as a novel type of catalyst supports because of their easy synthesis and functionalization, magnetic separation, good stability, low toxicity and cost [34]. A number of magnetically retrievable catalysts have been employed in a range of organic transformations [35][36][37] and some immobilization processes for functional ILs on MNPs supports have been developed [38][39][40]. Driven by the unique properties of magnetic nanoparticles and the potential applications of acidic ILs in catalysis, we have successfully prepared a magnetic nanoparticle supported acidic ionic liquid (AIL@MNP), which was found to be a highly efficient catalyst for the synthesis of benzoxanthenes through the MCRs [38].…”

Synthesis and Microbicidal Activity of Substituted 1,2,3-Triazoles having Amide and Hydroxy Functionality

“…in situ removal of water and moisture absorbing materials are the two options [25][26][27], which were often observed with minimum success and inconsistent yields [25][26][27]. Recent mechanism studies had suggested that moisture was not the real problem and the catalysts offering more surface area have proven to be more useful [28][29][30][31]. The use of Fe 3 O 4 @SiO 2 was first of its sort and near doubling of reaction yield is in expected lines considering our similar observation with thiophenes, terpyridine, quinazoline and isoxazole [23].…”