- Highly active hybrid mesoporous silica-supported base organocatalysts for C–C bond formation
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New base hybrid catalysts, based on silyl-derivatives of molecules carrying amino, diamino, pyrrolidine, pyrazolium and imidazolium functionalities have been successfully achieved through post synthetic grafting onto M41S-type support. Different character
- Erigoni,Hernández-Soto,Rey,Segarra,Díaz
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- Mesoporous polymeric catalysts with both sulfonic acid and basic amine groups for the one-pot deacetalization-Knoevenagel reaction
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A one-pot cascade reaction catalyzed by multifunctional catalysts is an economical and efficient pathway in modern organic synthesis. Herein, mesoporous polymeric materials with both sulfonic acid and basic amine groups have been synthesized by solvothermal-copolymerization of divinylbenzene (DVB) and 4-styrenesulfonic sodium (StSO3-Na+) with subsequent nitration, reduction of nitro to amino groups and acidification of sulfonic sodium to obtain P(DVB-NH2-StSO3H). The mesoporous polymeric bifunctional catalyst showed excellent activity and selectivity for one-pot cascade deacetalization-Knoevenagel condensation with facile recovery due to the isolated locations of the sulfonic acid and amino groups.
- Sun, Zunming,Yang, Xinyue,Huang, Xianpei,Zhang, Mengmeng,Bian, Guomin,Qi, Yonglin,Yang, Xinlin,Zhang, Wangqing
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- H3PW12O40/mpg-C3N4 as an efficient and reusable bifunctional catalyst in one-pot oxidation-Knoevenagel condensation tandem reaction
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A single-site bifunctional catalyst for the oxidation-Knoevenagel condensation tandem reaction was prepared by the immobilization of phosphotungstic acid (HPW) on mesoporous graphitic carbon nitride (mpg-C3N4) via electrostatic interaction (HPW/mpg-C3N4). The results of Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), solid-state 31P nuclear magnetic resonance (solid-state 31P NMR), zeta potentials, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) demonstrated that HPW was successfully immobilized on the protonated mpg-C3N4 by electrostatic interaction. The acid amounts of the catalysts were determined by NH3 temperature programmed desorption (NH3-TPD). The textural properties and morphology of HPW/mpg-C3N4 were characterized by N2 adsorption-desorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). 30% HPW/mpg-C3N4 shows the best catalytic performance in the tandem reaction with 98.4% benzyl alcohol conversion and 96.2% selectivity to benzylidene malononitrile. The excellent catalytic performance of 30% HPW/mpg-C3N4 in the tandem reaction is due to the good catalytic performance of HPW in the oxidation and Knoevenagel condensation, respectively. Furthermore, protonated mpg-C3N4 not only acts as a support to facilitate good dispersion of HPW but also promotes the Knoevenagel condensation reaction effectively. Moreover, the HPW/mpg-C3N4 catalyst could be recycled easily without significant loss of catalytic activity.
- Wang, Hefang,Wang, Cunyue,Yang, Yongfang,Zhao, Meng,Wang, Yanji
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- Preparation of Nitrogen-Doped Carbon from Polyacrylonitrile and its Application as a Solid-Base Catalyst
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N-doped carbon (N carbon) materials were prepared from a commercial polyacrylonitrile (PAN) by calcination and subsequent ammoxidation and these were used for a model reaction of Knoevenagel condensation of benzaldehyde and ethyl cyanoacetate. The catalyt
- Fujita, Shin-Ichiro,Katagiri, Ayaka,Watanabe, Hiroyuki,Asano, Sayaka,Yoshida, Hiroshi,Arai, Masahiko
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- Acid-base catalysts derived from weakly acidic ion exchange resin: Efficiency in the Knoevenagel condensation
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Weakly acidic cation-exchange resins in H+ form, partially neutralized with H2N(CH2)(n)N+Me3 OH- (n = 2-5), have been shown to catalyze the Knoevenagel condensation. The efficiency of catalysis depends on the aminoalkyl chain length and extent of neutralization.
- Saito,Goto,Honda,Fujii
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- Polystyrene Nanometer-Sized Particles Supported Alkaline Imidazolium Ionic Liquids as Reusable and Efficient Catalysts for the Knoevenagel Condensation in Aqueous Phase
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Abstract: Polystyrene nanometer-sized particles supported alkaline 1-propyl imidazolium ionic liquids catalysts (nano-PS-CH2-[pIM][B]) were prepared and characterized by FT-IR, SEM, TG/DTA, BET and particle size distribution analysis. The resul
- Ma, Min,Li, Hansheng,Yang, Wang,Wu, Qin,Shi, Daxin,Zhao, Yun,Feng, Caihong,Jiao, Qingze
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- Stereodiversified Modular Synthesis of Non-planar Five-Membered Cyclic N-Hydroxylamidines: Reactivity Study and Application to the Synthesis of Cyclic Amidines
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A modular, stereodiversified and scalable synthesis of 5-membered cyclic N-hydroxylamidines endowed with three contiguous stereogenic centres is reported. The synthesis utilizes 2-cyano-3-aryl-4-nitro-alkynoates as key building blocks, which are provided by a novel 3-component Knoevenagel -Michael addition manifold carried out as an aqueous emulsion (on water). The key building blocks are obtained as separable mixtures of two series of diastereomers: 2,3,4-syn,syn and 2,3,4-syn,anti. Both series were separately transformed into the corresponding 5-membered 3,4,5-trisubstituted N-hydroxylamidines by a tandem hydrogenation cyclization reaction (stereodiversification phase). These N-hydroxylamidines are functionalized at C3-methinic position of the ring (alpha to the amidine function) by a robust and unprecedented N-amidinoxyl radical-mediated auto-oxidation process (hydroxylation), or by a diastereoselective enamine-based C?C bond forming manifold (creation of an all-carbon quaternary centre). The outcome of the latter is biased by the relative disposition of substituents in the ring, affording C3-quaternized 5-membered cyclic N-hydroxylamidines or 2,9-diazabicyclo[4.3.0]non-1-en motives. Finally, the Ti(III)-reduction of these quaternized N-hydroxylamidines generates the corresponding amidines in excellent yields. (Figure presented.).
- Prieto-Ramírez, Mary Cruz,Fernández, Israel,da Silva, Ivan,González-Platas, Javier,de Armas, Pedro,García-Tellado, Fernando
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- Efficient bifunctional reactivity of K-doped CrO(OH) nanosheets: Exploiting the combined role of Cr(iii) and surface -OH groups in tandem catalysis
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This work reports the bifunctional catalytic activity of layered K-doped α-CrO(OH). The combined action of the redox active Cr(iii) and the surface hydroxyl groups was efficiently used to carry out 2-3 oxidation reactions in tandem followed by condensation/coupling reactions in one pot. Oxidation of benzyl alcohol followed by Knoevenagel condensation or coupling reactions forming C-C and C-N linkages in one pot is demonstrated. The catalyst has been characterized using XRD, IR, TGA, CO2-TPD, cyclic voltammetry, XPS and microscopic techniques to gain insight into the nature of active sites. The role of O- and O2- on the CrO(OH) catalyst in the bifunctional activity was studied using analytical techniques. Recyclability and leaching tests confirmed that K-α-CrO(OH) is a stable and environmentally safe catalyst.
- Vernekar, Dnyanesh,Ratha, Satyajit,Rode, Chandrashekhar,Jagadeesan, Dinesh
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- Magnetic superbasic proton sponges are readily removed and permit direct product isolation
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Workup in organic synthesis can be very time-consuming, particularly when using reagents with both a solubility similar to that of the desired products and a tendency not to crystallize. In this respect, reactions involving organic bases would strongly be
- Schneider, Elia M.,Raso, Renzo A.,Hofer, Corinne J.,Zeltner, Martin,Stettler, Robert D.,Hess, Samuel C.,Grass, Robert N.,Stark, Wendelin J.
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- Synthesis of cyclopropane-1,1,2,2-tetracarboxylic acid derivatives from aldehydes and CH-acids in the K2CO3/Bun 4NPF6/toluene heterogeneous system
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A one-pot method for the synthesis of cyclopropane-1,1,2,2-tetracarboxylic derivatives was developed starting from aldehydes and cyanoacetic and 2-bromomalonic esters under heterogeneous conditions (K2CO 3/PhMe) in the presence of re
- Kryshtal, G. V.,Zhdankina, G. M.,Zlotin, S. G.
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- From Bola-Surfactant Templated Bimetal Phosphites to the Design of Crystalline Inorganic Mesoporous Frameworks
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Reproducing inorganic modules in situ for pore augmentation of pure inorganic frameworks is challenging but can be a key to rational synthesis. After the first success of using monoamines of varied lengths as a template in producing a set of building bloc
- Huang, Hui-Lin,Huang, Wen-Yen,Wang, Sue-Lein
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- Highly active zinc oxide-supported lithium oxide catalyst for solvent-free Knoevenagel condensation
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Li2O/ZnO catalyst was prepared by wet impregnation method and characterized by XRD, SEM, EDX, FTIR, BET surface area and UV-Vis diffuse reflectance spectroscopy. This study revealed a decrease in average particle size and change in the shape of
- Basude, Manohar,Bhongiri, Yadagiri,Masula, Keshavulu,Pasala, Vijay Kumar,Puppala, Veerasomaiah,Sunkara, Prasad
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- Knoevenagel Condensations Catalyzed by New Oil Shale Recyclable Catalyst at Room Temperature and Assisted by Ultrasounds Irradiations
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Functionalized alkenes were successfully synthesized via a clean procedure in a short time by using a new recycled heterogeneous catalyst prepared from Moroccan oil shale, this catalyst is characterized by different technics such XRD, BET-BJH, MEB-EDS, an
- Bazi, Fathallaah,Elkouali, M. Hammed,Ennesyry, Elmustapha,Hamza, Mohammed,Hannache, Hassan,Mounir, Bahija,Talbi, Mohammed
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p. 1295 - 1301
(2022/01/24)
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- Synthesis of lithium/cesium-Zagronas from zagrosian natural asphalt and study of their activity as novel, green, heterogeneous and homogeneous nanocatalysts in the Claisen–Schmidt and Knoevenagel condensations
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A novel, heterogeneous and homogeneous basic nanocatalysts were synthesized by grafting of lithium and cesium on zagrosian natural asphalt sulfonate (Li/Cs-Zagronas). The activity of these catalysts was examined in the Claisen–Schmidt and Knoevenagel condensations under mild reaction conditions. Li/Cs-Zagronas were characterized by FT-IR spectroscopy, scanning electron microscopy, X-ray diffraction, energy-dispersive spectroscopy, inductively coupled plasma and thermogravimetric analysis techniques. These nanocatalysts were removed by simple filtration and reused several times without any deterioration of activity.
- Soleiman-Beigi, Mohammad,Ghalavand, Saba,Venovel, Hadis Gholami,Kohzadi, Homa
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p. 3267 - 3279
(2021/06/17)
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- Scalable and Recyclable All-Organic Colloidal Cascade Catalysts
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We report on the synthesis of core–shell microparticles (CSMs) with an acid catalyst in the core and a base catalyst in the shell by surfactant-free emulsion polymerization (SFEP). The organocatalytic monomers were separately copolymerized in three synthetic steps allowing the spatial separation of incompatible acid and base catalysts within the CSMs. Importantly, a protected and thermo-decomposable sulfonate monomer was used as acid source to circumvent the neutralization of the base catalyst during shell formation, which was key to obtain stable, catalytically active CSMs. The catalysts showed excellent performance in an established one-pot model cascade reaction in various solvents (including water), which involved an acid-catalyzed deacetalization followed by a base-catalyzed Knoevenagel condensation. The CSMs are easily recycled, modified, and their synthesis is scalable, making them promising candidates for organocatalytic applications.
- Chen, Chen,Gr?schel, André H.,Gramse, Christian,Janoszka, Nicole,Weberskirch, Ralf,Wong, Chin Ken
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supporting information
p. 237 - 241
(2020/10/30)
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- MOFs assembled from C 3symmetric ligands: Structure, iodine capture and role as bifunctional catalysts towards the oxidation-Knoevenagel cascade reaction
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Three new NiII/CoII-metal organic frameworks were self-assembled by the reaction of C3 symmetric 1,3,5-tribenzoic acid (H3BTC) and 2,4,6-tris(4-pyridyl)-1,3,5-triazine (4-TPT) ligands and NiII/CoII salts under solvothermal conditions. Isomorphous MOF1 and MOF2 exhibit a 3D pillar-layer framework based on binuclear M2(OH)(COO)2 units connected by tritopic BTC3- and 4-TPT ligands with a novel (3,5)-connected topology net. MOF3 displays a 3-fold interpenetrated 3D network exhibiting a (3,4)-connected topology net. The porous MOF3 can reversibly take up I2. The activated MOFs contain both Lewis acid (NiII center) and basic (uncoordinated pyridyl or carboxylic groups) sites, and act as bifunctional acid-base catalysts. The catalytic measurements demonstrate that the activated MOF3 exhibits good activities for benzyl alcohol oxidation and the Knoevenagel reaction and can be recycled and reused for at least four cycles without losing its structural integrity and high catalytic activity. Thus, the catalytic properties for the oxidation-Knoevenagel cascade reaction have also been studied.
- Zhang, Ying-Ying,Liu, Qing,Zhang, Lin-Yan,Bao, Yu-Mei,Tan, Jing-Yi,Zhang, Na,Zhang, Jian-Yong,Liu, Zhen-Jiang
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p. 647 - 659
(2021/01/28)
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- A facile microwave-assisted Knoevenagel condensation of various aldehydes and ketones using amine-functionalized metal organic frameworks
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An amine-functionalized metal organic framework (MOF) was used as highly efficient and recyclable heterogeneous catalyst for Knoevenagel condensation of various aromatic aldehydes and ketones in ethanol. The catalytic efficiency was demonstrated by the hi
- Lee, Ik-Mo,Lumbiny, Bilkis Jahan,Taher, Abu
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- Synthesis of highly substituted tetrahydroquinolines using ethyl cyanoacetate: Via aza-Michael-Michael addition
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A three-component cascade reaction involving 2-alkenyl aniline, aldehydes, and ethyl cyanoacetate in the presence of DBU to synthesize highly substituted 1,2,3,4-tetrahydroquinolines is reported. The reaction proceeded through the Knoevenagel condensation
- Chen, Chinpiao,Lee, Gene-Hsian,Palanimuthu, Arunan
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p. 13591 - 13600
(2020/04/23)
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- A Simple and Highly Versatile Procedure for the Knoevenagel Condensation Promoted by an Efficient, Eco-Friendly, and Recyclable nano-ZnO Catalyst
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Abstract: A simple, highly versatile, and efficient protocol for the synthesis of substituted olefins from various aromatic aldehydes and active methylene compounds by Knoevenagel condensation using an efficient, eco-friendly, and recyclable nano-ZnO cata
- Alam, M. M.,Asiri, Ya. I.,Sulthana, S. Sh.,Tasqeeruddin, S.
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p. 315 - 321
(2020/04/17)
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- Chitosan nanofiber-catalyzed highly selective Knoevenagel condensation in aqueous methanol
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A chitosan nanofiber (CsNF)-catalyzed Knoevenagel reaction in green solvent, namely aqueous methanol, was investigated. CsNFs solely catalyzed the desired C-C bond formations in high yield with high selectivity, while conventional small-molecule amines, such as n-hexylamine and triethylamine, inevitably promoted transesterification to produce a large amount of solvolysis byproducts. Structural and chemical analyses of CsNFs suggested that the unique nanoarchitecture, in which chitosan molecules were bundled to ensure the high accessibility of substrates to catalytic sites, was critical to the highly efficient Knoevenagel condensation. The products were obtained in high purity without solvent-consuming purification, and the CsNF catalyst was easily removed and recycled. This study highlights a novel and promising function of CsNFs in green catalysis as emerging polysaccharide-based nanofibers.
- Hatakeyama, Mayumi,Hirayama, Yusaku,Kanomata, Kyohei,Kitaoka, Takuya
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p. 26771 - 26776
(2020/08/13)
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- Potassium Natural Asphalt Sulfonate (K-NAS): Synthesis and characterization as a new recyclable solid basic nanocatalyst and its application in the formation of carbon–carbon bonds
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In this research, we synthesized and characterized a new heterogeneous basic nanocatalyst and its catalytic application was studied in the Claisen-Schmidt and Knoevenagel condensations. In order to prepare this nanocatalyst, first, the Iranian natural asphalt was sulfonated with the concentrated sulfuric acid and then, converted to the potassium natural asphalt sulfonate (K-NAS). In order to characterization of the nanocatalyst, used of FT-IR spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), inductively coupled plasma (ICP) and thermogravimetric analysis (TGA) techniques. This new basic heterogeneous nanocatalyst have advantages such as being eco-friendly, huge specific surface area, high reactivity and recyclability.
- Falah, Saeid,Soleiman-Beigi, Mohammad,Kohzadi, Homa
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- Synthesis of structurally enhanced magnetite cored poly(propyleneimine) dendrimer nanohybrid material and evaluation of its functionality in sustainable catalysis of condensation reactions
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The conventional method of dendrimer synthesis especially poly(propyleneimine) dendrimer (PPI) involves complicated reaction workup and tedious separation strategies. Since it has greater number of nitrogen atom in their structure, its applications are in
- Kannappan, Lakshmi,Rajmohan, Rangasamy
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- Ammonium chloride: An efficient and environmentally benign catalyst for knoevenagel condensation of carbonyl and active methylene compounds
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In the present study, a rapid, simple and an efficient procedure for the Knoevenagel condensation of various carbonyl and active methylene compounds in ethanol at a moderate temperature in the presence of a catalytic amount of an efficient, environmentall
- Tasqeeruddin,Asiri, Yahya I.,Mujahid Alam
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p. 3024 - 3028
(2021/01/06)
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- Overcoming acid–base copolymer neutralization using mesoporous carbon and its catalytic activity in the tandem deacetalization–Knoevenagel condensation reaction
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Abstract: Acid–base copolymer materials are of considerable interest because of their fundamental implications for acid–base bifunctional catalysis applications. However, quenching the acid and base sites of the copolymer with each other in free radical polymerizations is still challenging. Herein, we demonstrate that the polymerization of styrenesulfonic acid-co-4-vinylpyridine into the mesoporous carbon material (i.e., CMK-3) can control the chain growth polymerization and result in decreasing the interaction of the acid–base sites. The results showed that by using CMK-3, 40% of the acid and base sites of the copolymer remain in their original form while 60% of acid and base sites convert to the pyridinium and sulfonate forms. Furthermore, it is demonstrated that this material can be processed as a heterogeneous bifunctional acid–base catalyst in the tandem one-pot acid–base reaction (i.e., deacetalization–Knoevenagel condensation reaction) with a high catalytic activity in aqueous media. Graphic abstract: [Figure not available: see fulltext.].
- Javad Kalbasi, Roozbeh,Rahmati, Fatemeh,Mazaheri, Omid
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p. 3413 - 3430
(2020/05/16)
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- Imine-bridged periodic mesoporous organosilica as stable high-activity catalytic for Knoevenagel reaction in aqueous medium
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An imine-functionalized mesoporous solid base catalyst (BA@BE-PMO) was prepared by template agent-directed self-assembly condensation of bis[3-(triethoxysilyl)propyl]amine and 1,2-bis(triethoxysilyl)ethane in acid solution. The imine groups with catalytic
- Sun, Zechun,Wang, Yiran,Zhang, Zhiruo,Zhu, Fengxia,Zhao, Pusu,Li, Guisheng,Shao, Fengfeng,Rui, Jiahui
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p. 3107 - 3121
(2019/03/13)
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- Calcined Dolomite: An Efficient and Recyclable Catalyst for Synthesis of Α, Β-Unsaturated Carbonyl Compounds
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Abstract: Calcined dolomite was utilized as a low-cost and efficient catalyst for the Knoevenagel condensation of aldehydes with active methylene compounds such as malononitrile and ethyl cyanoacetate to afford substituted α, β-unsaturated carbonyl compou
- Yang, Hongyuan,Dong, Hao,Zhang, Tengfei,Zhang, Qi,Zhang, Guangwei,Wang, Peng,Liu, Qing
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p. 778 - 787
(2019/01/04)
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- Prolinamide functionalized polyacrylonitrile fiber with tunable linker length and surface microenvironment as efficient catalyst for Knoevenagel condensation and related multicomponent tandem reactions
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A series of new prolinamide polyacrylonitrile fiber catalysts with tunable length of alkyl linker and different linker group were prepared by covalent bonding for the first time and well characterized by mechanical strength, FT-IR, XRD, EA, TGA, SEM and water contact angel. The catalytic activities of these fiber catalysts were evaluated in Knoevenagel condensation and one-pot Knoevenagel-Michael multicomponent tandem reactions to synthesize α, β-unsaturated nitrile and 2-amino-4H-chromene derivatives in water. The result show that the suitable linker length attaching amines to fiber matrix as well as the constructed hydrophobic microenvironment by linker group within the surface layers of fiber materials effectively promotes the reactions. In addition, the good swollen capacity of fiber in solvent ensure that the reaction proceed well. Fiber catalyst PANPA?2F modified by prolinamide with a C2 alkyl chain exhibited the best catalytic performance and can be easily recovered and reused for at least ten consecutive cycles without significant loss of catalytic activity and active sites leaching.
- Zhu, Hai,Xu, Gang,Du, Huimin,Zhang, Chenlu,Ma, Ning,Zhang, Wenqin
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p. 217 - 229
(2019/05/16)
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- Synthesis of multifunctional polymer containing Ni-Pd NPs via thiol-ene reaction for one-pot cascade reactions
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Recently, acid–base bifunctional catalysts have been considered due to their abilities, such as the simultaneous activation of electrophilic and nucleophilic species and their high importance in organic syntheses. However, the synthesis of acid–base catalysts is problematic due to the neutralization of acidic and basic groups. This work reports a facial approach to solve this problem via the synthesis of a novel bifunctional polymer using inexpensive materials and easy methods. In this way, at the first step, heterogeneous poly (styrene sulfonic acid-n-vinylimidazole) containing pentaerythritol tetra-(3-mercaptopropionate) (PETMP) and trimethylolpropane trimethacrylate (TMPTMA) cross-linkers were synthesized in the pores of a mesoporous silica structure using click reaction as a novel bifunctional acid–base catalyst. After that, Ni-Pd nanoparticles supported on poly (styrenesulfonic acid-n-vinylimidazole)/KIT-6 as a novel trifunctional heterogeneous acid–base-metal catalyst was prepared. The prepared catalysts were characterized by various techniques like FT-IR, TGA, ICP-AES, DRS-UV, TEM, FE-SEM, EDS-Mapping, and XRD. The synthesized catalysts were efficiently used as bifunctional/trifunctional catalysts for one-pot, deacetalization-Knoevenagel condensation and one-pot, three-step and a sequential reaction containing deacetalization-Knoevenagel condensation-reduction reaction. It is important to note that the synthesized catalyst showing high chemo-selectivity for the reduction of nitro group, alkenyl double bond and ester group in the presence of nitrile. Moreover, it was found that the different nanoparticles including Ni, Pd, and alloyed Ni-Pd showing different chemo-selectivity and catalytic activity in the reaction.
- Javad Kalbasi, Roozbeh,Mesgarsaravi, Niloofar,Gharibi, Reza
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- Amino- and sulfo-bifunctionalized hyper-crosslinked organic nanotube frameworks as efficient catalysts for one-pot cascade reactions
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In this paper, novel amino- and sulfo-bifunctionalized hyper-crosslinked organic nanotube frameworks (H-ONTFs) were directly prepared by templating core-shell bottlebrush copolymers via a Friedel-Crafts (F-C) alkylation reaction, in which the acidic sites were anchored into the wall of nanotubes and basic sites were introduced onto the inner layer wall of nanotubes through a rational molecular design strategy. The resulting acid-base bifunctionalized H-ONTFs showed excellent catalytic activities for one-pot deacetalization-Knoevenagel cascade reactions due to their open-ended structure, large surface area and good multi-porosity interconnectivity.
- Meng, Guojie,Gao, Shengguang,Liu, Ying,Zhang, Li,Song, Chunmei,Huang, Kun
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supporting information
p. 2269 - 2273
(2019/02/05)
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- Precise Control of the Oriented Layered Double Hydroxide Nanosheets Growth on Graphene Oxides Leading to Efficient Catalysts for Cascade Reactions
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In recent years, great attention has been paid to cascade reactions, which can improve efficiency and reduce waste production by implementing several consecutive reactions. Herein, two bifunctional catalysts were successfully prepared by precise control of the oriented layered double hydroxides (LDHs) growth on graphene oxides (GO) using a single-drop and co-precipitation method, respectively. The resultant Ru/LDH-GO-P and Ru/LDH-GO-V composites were characterized by EXAFS, FT-IR, XRD, TG-DTA, BET, XPS, TEM, CO2-TPD, O2-TPD, etc. The catalytic performance of Ru/LDH-GO-P and Ru/LDH-GO-V for one-pot oxidation-Knoevenagel condensation reaction showed significant difference under the same experimental conditions, in which the Ru/LDH-GO-P showed 99 % conversion and 99 % selectivity, in marked contrast of 60.7 % conversion and 47.9 % selectivity using Ru/LDH-GO-V as catalyst. The large enhancement of the catalytic performance using Ru/LDH-GO-P can be attributed to the following reasons: 1) the Co3+ centers in Ru/LDH-GO-P can promote the formation of surface oxygen vacancies that can adsorb and activate O2 to get better performance; 2) the Ru/LDH-GO-P exhibited larger BET surface and more medium-strong basic active sites than the Ru/LDH-GO-V. Moreover, the Ru/LDH-GO-P catalyst can be easily recovered from the reaction system and reused for at least five times without obvious deterioration of its catalytic activity or structural integrity.
- Zhang, Wei,Wang, Zelin,Zhao, Yufei,Miras, Haralampos N.,Song, Yu-Fei
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p. 5466 - 5474
(2019/11/13)
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- Efficient Synthesis of Branched Polyamine Based Thermally Stable Heterogeneous Catalyst for Knoevenagel Condensation at Room Temperature
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Abstract: In this paper, a new convenient strategy for the synthesis of polyethylenimine functionalized Si-MCM-41 grafted on surface modified graphene oxide has been developed. The as-synthesised catalyst exerts good catalytic activity and reusability tow
- Chaudhuri, Haribandhu,Gupta, Radha,Dash, Subhajit
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p. 1703 - 1713
(2018/04/02)
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- An efficient Knoevenagel condensation of aldehydes with active methylene compounds over novel, robust CeZrO4?δ catalyst
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Abstract: In the present work, we explored novel CeZrO4?δ as a catalyst for Knoevenagel condensation of aldehydes with reactive methylene compounds like malononitrile and ethylcyanoacetate. For the present study, ceria, zirconia and CeZrO4
- Sahani, Amber J.,Burange, Anand S.,Jayaram, Radha V.
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p. 7805 - 7814
(2018/09/12)
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- Development of Amine Functionalized Wrinkled Silica Nanospheres and Their Application as Efficient and Recyclable Solid Base Catalyst
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Abstract: Amine functionalized wrinkled silica nanospheres (WSiO2–NH2) were successfully synthesized by using a simple biphase sol–gel approach. The prepared silica nanospheres were characterized by using various techniques, such as
- Shabir, Javaid,Garkoti, Charu,Surabhi,Sah, Digvijay,Mozumdar, Subho
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p. 194 - 204
(2017/11/20)
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- DABCO-catalyzed Knoevenagel condensation of aldehydes with ethyl cyanoacetate using hydroxy ionic liquid as a promoter
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N-(2-Hydroxy-ethyl)-pyridinium chloride ([HyEtPy]Cl) was synthesized and explored as a novel promoter for 1,4-diazabicyclo [2.2.2] octane (DABCO)-catalyzed Knoevenagel condensation reactions, which showed better catalytic activity compared to other ionic liquid (IL) that had no hydroxyl group attached to the IL scaffold. The effect of hydrogen bond formation between the hydroxyl group of [HyEtPy]Cl and the carbonyl group of aldehyde played an important role in the Knoevenagel condensation reaction. In the [HyEtPy]Cl-H2O-DABCO composite system, Knoevenagel condensation reactions proceeded smoothly and cleanly, and the corresponding Knoevenagel condensation products were obtained in good to excellent yields in all cases examined. This protocol provides a versatile solvent-catalyst system, which has notable advantages such as being eco-friendly, ease of work-up and convenient reuse of the ionic liquid.
- Meng, Dan,Qiao, Yongsheng,Wang, Xin,Wen, Wei,Zhao, Sanhu
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p. 30180 - 30185
(2018/09/11)
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- Acid-base bifunctional amphiphilic organic nanotubes as a catalyst for one-pot cascade reactions in water
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A novel acid-base bifunctional amphiphilic organic nanotube (acid-base-nanotube) containing 1-(2-(prop-2-yn-1-yloxy)ethyl)-1H-imidazole (PEI) groups as basic sites on the wall and benzenesulfonic acid (BSA) groups as acidic sites on the corona of nanotubes was successfully synthesized by a combination of molecular-template core-shell bottlebrush copolymers and click reaction. Owing to the hydrophobic cavity microenvironments, a hydrophilic corona, and site-isolation features of organic tubular structures, the resultant acid-base-nanotube showed high catalytic performance for one-pot deacetalization-Knoevenagel cascade reactions in water.
- Xiong, Linfeng,Zhang, Hui,He, Zidong,Wang, Tianqi,Xu, Yang,Zhou, Minghong,Huang, Kun
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supporting information
p. 1368 - 1372
(2018/02/06)
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- Double-shelled hollow mesoporous silica nanospheres as an acid-base bifunctional catalyst for cascade reactions
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Double-shelled hollow mesoporous silica nanospheres (HMS-Al@MS-NH2) have been successfully obtained using the shell-by-shell strategy, by which the isolated acidic (-Al) and basic (-NH2) sites were spatially incorporated in different shells. The characterization results indicate that HMS-Al@MS-NH2 possesses a hollow void and mesopores in both shells, and this favors the mass transfer of the reactants and products. As a spatially isolated acid-base bifunctional catalyst, HMS-Al@MS-NH2 proved to exhibit high catalytic performances in the one-pot deacetalization-Knoevenagel cascade reaction. Under the optimized conditions, the conversion of benzaldehyde dimethyl acetal approached ca. 100% for 2 h at 110 °C, mainly attributed to the isolated acidic and basic sites and to the hollow architecture and mesopores in the shells. Notably, the catalyst could be reused up to 4 times without obvious loss of activity and selectivity, indicating the high stability of the active acidic and basic sites in the framework. Moreover, the double-shelled hollow mesoporous silica spheres are also active and selective for the other cascade sequence of the deacetalization-Henry reaction.
- You, Chunzi,Yu, Chunqi,Yang, Xiaohui,Li, Yudong,Huo, Hang,Wang, Zhe,Jiang, Yanqiu,Xu, Xianzhu,Lin, Kaifeng
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p. 4095 - 4101
(2018/03/21)
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- Efficient and recyclable novel Ni-based metal–organic framework nanostructure as catalyst for the cascade reaction of alcohol oxidation–Knoevenagel condensation
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A novel Ni-based metal–organic framework (Ni-MOF) with a Schiff base ligand as an organic linker, Ni3(bdda)2(OAc)2?6H2O (H2bdda?=?4,4′-[benzene-1,4-diylbis(methylylidenenitrilo)]dibenzoic acid), was synthesized and characterized using powder X-ray powder diffraction, thermogravimetric analysis, Brunauer–Emmett–Teller measurements, inductively coupled plasma atomic emission spectroscopy, transmission electron microscopy, elemental analysis and Fourier transform infrared spectroscopy. The synthesized Ni-MOF exhibited a high catalytic activity in benzyl alcohol oxidation using tert-butyl hydroperoxide under solvent-free conditions. Also, the efficiency of the catalyst was investigated in the cascade reaction of oxidation–Knoevanagel condensation under mild conditions. The Ni-MOF catalyst could be recovered and reused four times without significant reduction in its catalytic activity.
- Aryanejad, Sima,Bagherzade, Ghodsieh,Farrokhi, Alireza
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- Synthesis and characterization of a Ni nanoparticle stabilized on Ionic liquid-functionalized magnetic Silica nanoparticles for tandem oxidative reaction of primary alcohols
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In this research, preparation of the magnetic nanoparticle, coating by a silica shell using (3-aminopropyl) triethoxysilane and synthesis of a novel sulfonic acid-substituted imidazolium-based ionic liquid onto the surface of these particles via a multi-component reaction, is described. The functionalized nanoparticles was loaded by Ni nanoparticles and characterized by means of techniques such as XRD, FTIR, SEM, EDX, TEM, TGA and ICP-OES. The nanostructures have spherical shapes that ranged in size from 80 to 100?nm. The catalytic activity of these nanoparticles was tested in aerobic oxidation of primary alcohols that showed good performance in the wide range of primary alcohols in water at mild reaction conditions. As a second step of this work, the tandem oxidative synthesis of alkylacrylonitriles and bisindolylmethanes were investigated using primary alcohols under oxidation conditions. This catalyst system can be recovered using external magnet and reused for five consecutive cycles without significantly less of its activity.
- Hosseinzadeh-Khanmiri, Rahim,Kamel, Yaser,Keshvari, Zahra,Mobaraki, Ahmad,Shahverdizadeh, Gholam Hossein,Vessally, Esmail,Babazadeh, Mirzaagha
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- Direct synthesis and application of bridged diamino-functionalized periodic mesoporous organosilicas with high nitrogen contents
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Bridged diamino-functionalized periodic mesoporous organosilicas [BD-PMO(Et), Et = ethyl] materials were synthesized directly by co-condensation of 2-bis (triethoxysilyl)ethane (BTEE) and 1,4-bis[3-(tirmethoxysilyl)-propyl]ethylenediamino (BTMSEN) under acidic conditions with pluronic triblock copolymer P123 as a template. The nitrogen content in BD-PMO(Et) could be adjusted up to 40% without disturbing the ordered mesoporous structure. These materials were proved to be effective heterogeneous catalysts for the liquid-phase reactions such as Knoevenagel and Henry condensations as well as in the intermolecular cross-double-Michael addition reaction between α-methyl-β-nitrostyrene and α, β-unsaturated ketone. They exhibited comparable catalytic activities with homogeneous catalyst piperazine and can be reused for several times without any negative environmental impact.
- Zhu, Feng-Xia,Zhao, Pu-Su,Sun, Xiao-Jun,An, Li-Tao,Deng, Yong,Wu, Jia-Min
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- Isocyanate-functionalized starch as biorenewable backbone for the preparation and application of poly(ethylene imine) grafted starch
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Reactive supports provide versatile platforms for surface decoration, affording various functional materials widely used in chemical and biological research. Considering the biodegradability, biocompatibility, and economy, starch is a suitable support med
- Fu, Lixia,Peng, Yanqing
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p. 1547 - 1554
(2017/07/18)
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- Synthesis and characterization of bromine source supported on magnetic Fe3O4 nanoparticles: A new, versatile and efficient magnetically separable catalyst for organic synthesis
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Tribenzylammonium tribromide supported onto magnetic nanoparticles (Br3-TBA-Fe3O4) as a bromine source was successfully synthesized and characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry. The synthesized catalyst is shown to be a versatile and highly efficient heterogeneous catalyst for the Knoevenagel condensation and synthesis of 2,3-dihydroquinazolin-4(1H)-one and polyhydroquinoline derivatives. To the best of the authors' knowledge, this is the first report of the use of a bromine source immobilized on Fe3O4 nanoparticles as a magnetically separable catalyst for these reactions. The nanosolid catalyst can be magnetically recovered and reused readily several times without significant loss in catalytic efficiency.
- Shiri, Lotfi,Ghorbani-Choghamarani, Arash,Kazemi, Mosstafa
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- Magnetic Fe3O4 nanoparticles supported amine: a new, sustainable and environmentally benign catalyst for condensation reactions
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Abstract: Diethylenetriamine immobilized on magnetic Fe3O4 nanoparticles (DETA-Fe3O4) was successfully prepared as a new and well dispersed magnetically separable amine catalyst. The structure of the resulting catalyst was well characterized by a series of analysis techniques such as FT-IR, SEM, EDX, VSM, TGA and XRD. The catalytic activity of DETA-Fe3O4 was evaluated with Knoevenagel condensation of active methylene compounds with aromatic aldehydes. Interestingly, the cyclocondensation of anthranilamide and aldehydes were effectively catalyzed by DETA-Fe3O4 in water, and the desired products (2,3-dihydroquinazoline-4(1H)-ones) were afforded in admirable yields. Catalysis research under aqueous medium (water) also makes this synthetic protocol ideal and fascinating from the environmental point of view. The amine catalyst can be magnetically recovered after the reaction and can be reused many times without appreciable decrease in activity.
- Shiri, Lotfi,Kazemi, Mosstafa
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p. 4813 - 4832
(2017/07/22)
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- Phosphorous acid functionalized polyacrylonitrile fibers with a polarity tunable surface micro-environment for one-pot C-C and C-N bond formation reactions
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The preparation and application of fiber catalysts have attracted much attention. However, research on the effect of the micro-environment of fiber catalysts on the catalytic activities though of special importance is limited. In this work, a novel strategy for the synthesis of phosphoric acid-functionalized polyacrylonitrile fibers with a polarity tunable surface micro-environment by hydrophobic groups for one-pot C-C and C-N bond formation reactions is reported. The special hydrophobic surface micro-environment of the fiber catalysts is proven to promote the catalytic activities impressively in cyclocondensation of β-ketoesters with 2-aminobenzamides, the Knoevenagel condensation as well as the multi-component Biginelli reactions in green solvents. Both the surface synergy of the catalytic sites and hydrophobic auxiliary groups (benzyl or n-butyl) in the surface of fiber catalysts and interface acceleration in reaction medium play an important role in the highly efficient promotion of catalytic activity. Thereby a surface synergistic mechanism is proposed to explain the micro-environment effect. In addition, the fiber catalysts could be simply separated from the reaction system using tweezers and directly used in the next cycle without further treatment. Importantly, even after 10 reaction cycles in water or ethanol, there is no significant loss in their catalytic activity. The results indicate that the phosphoric acid functionalized fibers show green and sustainable potential for industrial production.
- Xu, Gang,Wang, Lu,Li, Mengmeng,Tao, Minli,Zhang, Wenqin
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supporting information
p. 5818 - 5830
(2017/12/26)
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- Green synthesis of a nano salt and its application as multifunctional organocatalyst for Knoevenagel condensation
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1,2-Ethanediammonium 3-hydroxypropane-1-sulfonate [(EDA)(HPS)] as a novel nano multifunctional organosalt was synthesized via a simple and green chemical route and characterized using various techniques such as proton nuclear magnetic resonance (1/s
- Honarmand, Moones
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p. 6421 - 6432
(2017/10/05)
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- Synthesis and characterization of bromine source immobilized on diethylenetriamine-functionalized magnetic nanoparticles: A novel, versatile and highly efficient reusable catalyst for organic synthesis
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Bromine source immobilized on magnetic nanoparticles functionalized with diethylenetriamine was successfully synthesized and characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometry, thermogravimetric analysis and X-ray diffraction. The catalytic activity in the synthesis of 2,3-dihydroquinazoline-4(1H)-one and polyhydroquinoline derivatives and in Knoevenagel condensation was studied. The bromine catalyst can be magnetically recovered and reused several times without significant loss of its catalytic activity. All products were obtained in high to excellent yields.
- Shiri, Lotfi,Rahmati, Sadegh,Ramezani Nejad, Zahra,Kazemi, Mosstafa
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- PhI(OAc)2 mediated an efficient Knoevenagel reaction and their synthetic application for coumarin derivatives
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A phenyliododiacetate (PhI(OAc)2) mediated an efficient and novel protocol for the Knoevenagel reaction has been successfully accomplished. A base free, simple and straightforward method afforded wide substrate scope and good functional group tolerance, having high yields (80–92%) under environmentally benign and mild reaction conditions.
- Khan, Danish,Mukhtar, Sayeed,Alsharif, Meshari A.,Alahmdi, Mohammed Issa,Ahmed, Naseem
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supporting information
p. 3183 - 3187
(2017/07/18)
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- A novel bifunctional Pd-ZIF-8/rGO catalyst with spatially separated active sites for the tandem Knoevenagel condensation-reduction reaction
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A novel bifunctional catalyst with spatially separated active sites was prepared by the immobilization of Pd nanoparticles (NPs) via covalent interaction and coordination of a zeolitic imidazolate framework (ZIF-8) on the surface of graphene oxide (GO), respectively, which was used as an efficient catalyst for the Knoevenagel condensation-reduction tandem reaction. The results of Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, UV-vis spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) demonstrated that Pd and ZIF-8 were successfully immobilized on the surface of GO, and the GO was reduced to reduced graphene oxide (rGO) using NaBH4 as the reductant in the preparation of Pd-ZIF-8/rGO. The textural properties and morphology of Pd-ZIF-8/rGO were characterized by N2 adsorption-desorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Pd-ZIF-8/rGO shows excellent catalytic performance in the tandem reaction with 100% benzaldehyde conversion and 98.3% selectivity to benzylmalononitrile. The excellent catalytic performance of Pd-ZIF-8/rGO in the tandem reaction is due to the high catalytic activities of spatially separated Pd NPs and ZIF-8 active sites and concentrated reactants on the surface of Pd-ZIF-8/rGO due to the π-π interaction between rGO and the reactants. The anchoring and stabilization effects of oxygenated groups of GO inhibit the aggregation and leakage of active sites, leading to good catalytic recyclability with almost unchanged catalytic activity for more than eight cycles in the tandem reaction.
- Wang, Hefang,Wang, Yansu,Jia, Aizhong,Wang, Cunyue,Wu, Luming,Yang, Yongfang,Wang, Yanji
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p. 5572 - 5584
(2017/12/07)
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- Amine-functionalized Metal-Organic Frameworks: An Efficient and Recyclable Heterogeneous Catalyst for the Knoevenagel Condensation Reaction
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A highly efficient and reusable catalyst based on metal-organic frameworks (MOF) has been synthesized by post-functionalization and applied in Knoevenagel condensations of various aldehydes and ketones. The catalytic efficiency was demonstrated by the hig
- Taher, Abu,Lee, Dong-Jin,Lee, Byoung-Ki,Lee, Ik-Mo
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supporting information
p. 1433 - 1437
(2016/06/01)
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- Tailoring a magnetically separable NiFe2O4nanoparticle catalyst for Knoevenagel condensation
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A magnetically separable NiFe2O4nanoparticle catalyst was prepared readily via a simple one-step hydrothermal process. The catalytic performance of this hetero-nanostructure was investigated by Kneovenagel condensation with aldehydes
- Li, Qichen,Wang, Xiaozhong,Yu, Yanyun,Chen, Yingqi,Dai, Liyan
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p. 8358 - 8363
(2016/12/02)
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- Fe3O4@UiO-66-NH2 core–shell nanohybrid as stable heterogeneous catalyst for Knoevenagel condensation
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Magnetic separation is an attractive alternative to filtration or centrifugation for separating solid catalysts from a liquid phase. Here, core-shell Fe3O4@UiO-66-NH2nanohybrids with well-defined structures were constructe
- Zhang, Yanmei,Dai, Tianlin,Zhang, Fan,Zhang, Jing,Chu, Gang,Quan, Chunshan
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p. 2106 - 2113
(2017/01/16)
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- Synthesis and characterization of ionic liquid based bifunctional periodic mesoporous organosilica supported potassium carbonate as very efficient nanocatalyst for the Knoevenagel condensation
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A novel ionic liquid based bifunctional periodic mesoporous organosilica supported potassium carbonate (BPMO-IL-KCO3) is prepared, characterized and its catalytic efficiency is studied in the Knoevenagel reaction. The BPMO-IL-KCO3 wa
- Elhamifar, Dawood,Kazempoor, Somayeh
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- Amine-functionalized ionic liquid-based mesoporous organosilica as a highly efficient nanocatalyst for the Knoevenagel condensation
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A novel amine-functionalized ionic liquid-based periodic mesoporous organosilica (PMO-IL-NH2) was prepared and characterized and its catalytic performance was investigated in the Knoevenagel reaction. PMO-IL-NH2 was prepared by simul
- Elhamifar, Dawood,Kazempoor, Somayeh,Karimi, Babak
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p. 4318 - 4326
(2016/07/06)
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- Adenine-Based Coordination Polymers: Synthesis, Structure, and Properties
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A solvothermal reaction of metal nitrate (M = Zn, Cd), cyclohexanedicarboxylic acid, and adenine resulted in the isolation of three new coordination polymers, [Zn4(1,4-CHDA)2.5(ad)3·2H2O] 7H2O 2DMA (C
- Sushrutha,Hota, Raghunandan,Natarajan, Srinivasan
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supporting information
p. 2962 - 2974
(2016/07/14)
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- Highly stable naphthalene core based novel cleft-shaped strain molecule: Influence of intermolecular H-bonding architectures
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The significance of intermolecular classical and non-classical H-bonding interactions in the stabilization of a naphthalene core based conformationally rigid cleft-shaped 1,5-dioxocin (BNAP) is presented here. The importance of H-bonding interactions to a
- Panja, Sumit Kumar,Dwivedi, Nidhi,Saha, Satyen
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p. 59574 - 59581
(2016/07/06)
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