- Ligand-free copper nanoparticle promoted N-arylation of azoles with aryl and heteroaryl iodides
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A relatively mild, efficient, and inexpensive method for the nucleophilic aromatic substitution of the N-H heterocycles with various aryl and heteroaryl iodides using copper nanoparticles (Cu-NP) is reported. The coupling reaction has been successfully ac
- Pai, Gita,Chattopadhyay, Asoke P.
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- Visible-light-induced aerobic C3-H fluoroalkoxylation of quinoxalin-2(1: H)-ones with fluoroalkyl alcohols
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A novel and efficient method of visible-light-induced C3-H fluoroalkoxylation of quinoxalin-2(1H)-ones with fluoroalkyl alcohols is developed. This approach uses readily available fluoroalkyl alcohols as fluoroalkoxylation reagents and displays a wide substrate scope, providing the fluoroalkoxylated products in moderate to good yields. Compared with the previous method, such a transformation uses oxygen as an oxidant, which avoids the utilization of plenty of PhI(TFA)2. In addition, this strategy also gives a practical tool for the rapid synthesis of histamine-4 receptor antagonist and new N-containing bidentate ligands. A radical mechanism was suggested according to the results of control experiments.
- Xu, Xiaobo,Xia, Chengcai,Li, Xiaojun,Sun, Jian,Hao, Liqiang
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- Exploration of Catalytic Activity of Quercetin Mediated Hydrothermally Synthesized NiO Nanoparticles Towards C–N Coupling of Nitrogen Heterocycles
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Abstract: A new approach towards the preparation of phase pure NiO nanoparticles via quercetin mediated hydrothermal method is proposed in this work. The performance of quercetin as capping agent is found to be good. The XRD and SEM results confirm that the NiO nanoparticles prepared with quercetin are smaller in size and have refined morphology than that prepared without quercetin. Thermal stability, elemental composition and particle size of prepared nanoparticles have been revealed by TG-DSC, EDAX and HR-TEM analysis respectively. N2 adsorption–desorption isotherm (BET) analysis was done to reveal specific surface area. The prepared NiO nanoparticles act as cost effective, environmental friendly and efficient catalyst for the C–N cross coupling of indole and electron deficient pyrrole, under very mild reaction conditions. The catalytic system is able to tolerate many functional groups with different electronic and structural properties. Hence the present catalytic system may be possibly applied in large scale synthesis. Graphic Abstract: [Figure not available: see fulltext.].
- Krishnaveni,Lakshmi,Kadirvelu,Kaveri
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- N-substituted aminobiphenyl palladacycles stabilized by dialkylterphenyl phosphanes: Preparation and applications in C[sbnd]N cross-coupling reactions
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Neutral and cationic N-methyl- and N-phenyl-2-aminobiphenyl methanesulfonate palladacycles stabilized with dialkylterphenyl phosphanes have been prepared and characterized. Neutral structures are favored with the less bulky phosphane PMe2ArXyl2, L1, while more sterically demanding ligands PiPr2ArXyl2, L3, and PCyp2ArXyl2 (Cyp = cyclopentyl), L4, lead to cationic complexes in which the phosphane exhibits a bidentate κ1-P, η1-Carene coordination mode involving one of the ipso carbon atoms of a flanking terphenyl aryl ring. The complexes were evaluated for activity in C[sbnd]N cross-coupling reactions and [Pd(N-methyl-2-aminobiphenyl)L4](OMs) (OMs = mesylate) was identified as the most efficient precatalyst, facilitating the coupling of aryl chlorides with secondary and primary amines and indoles.
- Monti, Andrea,Rama, Raquel J.,Gómez, Beatriz,Maya, Celia,álvarez, Eleuterio,Carmona, Ernesto,Nicasio, M. Carmen
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supporting information
(2021/01/19)
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- Copper nanoparticle anchored biguanidine-modified Zr-UiO-66 MOFs: a competent heterogeneous and reusable nanocatalyst in Buchwald-Hartwig and Ullmann type coupling reactions
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We have designed a functionalized metal-organic framework (MOF) of UiO topology as a support, with an extremely high surface area, adjustable pore sizes and stable crystalline coordination polymeric structure and implanted copper (Cu) nanoparticles thereon. The core three dimensional Zr-derived MOF (UiO-66-NH2) was modified with a biguanidine moiety following a covalent post-functionalization approach. The morphological and physicochemical features of the material were determined using analytical methods such as FT-IR, SEM, TEM, EDX, atomic mapping, XRD and ICP-OES. The SEM and XRD results justified the unaffected morphology of Zr-MOF after structural modifications. The as-synthesized UiO-66-biguanidine/Cu nanocomposite was catalytically explored in the aryl and heteroaryl Buchwald-Hartwig C-N and Ullmann type C-O cross coupling reactions with excellent yields. A library of biaryl amine and biaryl ethers was synthesized over the catalyst under mild and green conditions. Furthermore, the catalyst was isolated by centrifugation and recycled 11 times with no significant copper leaching or change in its activity.
- Veisi, Hojat,Neyestani, Narges,Pirhayati, Mozhgan,Ahany Kamangar, Sheida,Lotfi, Shahram,Tamoradi, Taiebeh,Karmakar, Bikash
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p. 22278 - 22286
(2021/07/02)
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- Functionalization of superparamagnetic Fe3O4@SiO2 nanoparticles with a Cu(II) binuclear Schiff base complex as an efficient and reusable nanomagnetic catalyst for N-arylation of α-amino acids and nitrogen-containing heterocycles with aryl halides
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Fe3O4@SiO2 nanoparticles was functionalized with a binuclear Schiff base Cu(II)-complex (Fe3O4@SiO2/Schiff base-Cu(II) NPs) and used as an effective magnetic hetereogeneous nanocatalyst for the N-arylation of α-amino acids and nitrogen-containig heterocycles. The catalyst, Fe3O4@SiO2/Schiff base-Cu(II) NPs, was characterized by Fourier transform infrared (FTIR) and ultraviolet-visible (UV-vis) analyses step by step. Size, morphology, and size distribution of the nanocatalyst were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and dynamic light scatterings (DLS) analyses, respectively. The structure of Fe3O4 nanoparticles was checked by X-ray diffraction (XRD) technique. Furthermore, the magnetic properties of the nanocatalyst were investigated by vibrating sample magnetometer (VSM) analysis. Loading content as well as leaching amounts of copper supported by the catalyst was measured by inductive coupled plasma (ICP) analysis. Also, thermal studies of the nanocatalyst was studied by thermal gravimetric analysis (TGA) instrument. X-ray photoelectron spectroscopy (XPS) analysis of the catalyst revealed that the copper sites are in +2 oxidation state. The Fe3O4@SiO2/Schiff base-Cu(II) complex was found to be an effective catalyst for C–N cross-coupling reactions, which high to excellent yields were achieved for α-amino acids as well as N-hetereocyclic compounds. Easy recoverability of the catalyst by an external magnet, reusability up to eight runs without significant loss of activity, and its well stability during the reaction are among the other highlights of this catalyst.
- Sardarian,Kazemnejadi,Esmaeilpour
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- Palladium-Catalyzed Three-Component Regioselective Dehydrogenative Coupling of Indoles, 2-Methylbut-2-ene, and Carboxylic Acids
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Five-carbon (C5) structural units are the fundamental building blocks of many natural products. An unprecedented palladium-catalyzed three-component dehydrogenative cascade coupling of indoles, 2-methylbut-2-ene, and carboxylic acids has been developed. The approach enables the straightforward introduction of a C3′-bonded five-carbon structural unit with a tertiary alcohol quaternary carbon center into indoles. The protocol employs 2-methylbut-2-ene as the C5 source and is featured by a broad substrate scope, atom and step economies, and high chemo- and regioselectivies.
- Guo, Rui-Li,Jia, Qiong,Wang, Meng-Yue,Wang, Yong-Qiang,Yang, Jin-Hui,Zhang, Xing-Long,Zhao, Bao-Yin
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supporting information
p. 9574 - 9579
(2021/12/14)
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- Preparation method of N-arylindole under copper catalysis
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The invention provides a preparation method of N-arylindole under copper catalysis. The preparation method comprises the following steps: S1, selecting a proper amount of a reaction reagent, a catalyst, a solvent and the like; S2, sequentially adding the
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Paragraph 0048-0061; 0064-0066; 0083-0084
(2021/07/08)
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- Dialkylterphenyl Phosphine-Based Palladium Precatalysts for Efficient Aryl Amination of N-Nucleophiles
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A series of 2-aminobiphenyl palladacycles supported by dialkylterphenyl phosphines, PR2Ar′ (R=Me, Et, iPr, Cyp (cyclopentyl), Ar′=ArDipp2, ArXyl2f, Dipp (2,6-C6H3-(2,6-C6H3-(CHMe2)2)2), Xyl=xylyl) have been prepared and structurally characterized. Neutral palladacycles were obtained with less bulky terphenyl phosphines (i.e., Me and Et substituents) whereas the largest phosphines provided cationic palladacycles in which the phosphines adopted a bidentate hemilabile k1-P,η1-Carene coordination mode. The influence of the ligand structure on the catalytic performance of these Pd precatalysts was evaluated in aryl amination reactions. Cationic complexes bearing the phosphines PiPr2ArXyl2 and PCyp2ArXyl2 were the most active of the series. These precatalysts have demonstrated a high versatility and efficiency in the coupling of a variety of nitrogen nucleophiles, including secondary amines, alkyl amines, anilines, and indoles, with electronically deactivated and ortho-substituted aryl chlorides at low catalyst loadings (0.25–0.75 mol % Pd) and without excess ligand.
- Rama, Raquel J.,Maya, Celia,Nicasio, M. Carmen
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supporting information
p. 1064 - 1073
(2020/01/25)
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- Ligand and Cu freeN-arylation of indoles, pyrroles and benzylamines with aryl halides catalyzed by a Pd nanocatalyst
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Herein, theN-arylation of aromatic heterocycles like indoles and pyrroles is reported by a Pd nanocatalyst under ligand- and Cu-free conditions. The reaction conditions tolerate several functional groups and work very efficiently for aryl iodides and bromides. Aryl chlorides are also successful as the coupling partners albeit with lower yields. The methodology is also applicable for theN-arylation of aliphatic primary amines as demonstrated by the reactions of benzylamine with several aryl iodides as well as bromides. The recyclable Pd nanocatalyst catalyzes the reaction by a heterogeneous mechanism, which has been demonstrated by several techniques including the three phase test and thein situICP-MS analysis of the reaction mixture.
- Paul, Abhijit,Chatterjee, Debnath,Banerjee, Srirupa,Yadav, Somnath
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supporting information
p. 14447 - 14452
(2020/09/21)
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- Cu(i) based catalysts derived from bidentate ligands and studies on the effect of substituents for: N -arylation of benzimidazoles and indoles
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A family of Cu(i) complexes [Cu(L1-4)(Cl)(PPh3)] (C1-C4) were synthesized from bidentate ligands L1-L4 (where L1 = (E)-2-(2-benzylidene-1-phenylhydrazinyl)pyridine, L2 = (E)-N,N-dimethyl-4-((2-phenyl-2-(pyridin-2-yl)hydrazono)methyl)aniline, L3 = (E)-2-(2
- Kumari, Sheela,Ratnam, Anand,Mawai, Kiran,Chaudhary, Virendra Kumar,Mohanty, Aurobinda,Ghosh, Kaushik
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p. 19591 - 19597
(2020/12/05)
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- N -Arylation of (hetero)arylamines using aryl sulfamates and carbamates via C-O bond activation enabled by a reusable and durable nickel(0) catalyst
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An effective and general aryl amination protocol has been developed using a magnetically recoverable Ni(0) based nanocatalyst. This new stable catalyst was prepared on Fe3O4@SiO2 modified by EDTA and investigated by FT-IR, EDX, TEM, XRD, DLS, FE-SEM, XPS, NMR, TGA, VSM, ICP and elemental analysis techniques. The reaction proceeded via carbon-oxygen bond cleavage of (hetero)aryl carbamates and sulfamates under simple and mild conditions without the use of any external ligands. This method demonstrated functional group tolerance in the N-arylation of various nitrogen-containing compounds as well as aliphatic amines, anilines, pyrroles, pyrazoles, imidazoles, indoles, and indazoles with good to excellent yields. Furthermore, the catalyst could be easily recovered by using an external magnetic field and directly reused at least six times without notable reduction in its activity. This journal is
- Dindarloo Inaloo, Iman,Majnooni, Sahar,Eslahi, Hassan,Esmaeilpour, Mohsen
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p. 13266 - 13278
(2020/10/07)
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- Direct C3-Selective Arylation of N-Unsubstituted Indoles with Aryl Chlorides, Triflates, and Nonaflates Using a Palladium-Dihydroxyterphenylphosphine Catalyst
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A palladium-dihydroxyterphenylphosphine (DHTP) catalyst was successfully applied to the direct C3-arylation of N-unsubstituted indoles with aryl chlorides, triflates, and nonaflates. This catalyst showed C3-selectivity, whereas catalysts with other structurally related ligands exhibited N1-selectivity. Complex formation between the lithium salts of the ligand and the indole is assumed to accelerate the arylation at the C3 position. Reactions using 3-alkylindoles afforded 3,3-disubstituted indolenines, which can be further converted to the corresponding indoline derivatives.
- Yamaguchi, Miyuki,Hagiwara, Ryoya,Gayama, Kanami,Suzuki, Kohei,Sato, Yusuke,Konishi, Hideyuki,Manabe, Kei
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p. 10902 - 10912
(2020/09/23)
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- Exhaustive Reduction of Esters Enabled by Nickel Catalysis
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We report a one-step procedure to directly reduce unactivated aryl esters into their corresponding tolyl derivatives. This is achieved by an organosilane-mediated ester hydrosilylation reaction and subsequent Ni/NHC-catalyzed hydrogenolysis. The resulting conditions provide a direct and efficient alternative to multi-step procedures for this transformation that often require the use of hazardous metal hydrides. Applications in the synthesis of -CD3-containing products, derivatization of bioactive molecules, and chemoselective reduction in the presence of other C-O bonds are demonstrated.
- Cook, Adam,Prakash, Sekar,Zheng, Yan-Long,Newman, Stephen G.
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supporting information
p. 8109 - 8115
(2020/05/20)
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- Iron oxide encapsulated by copper-Apatite: An efficient magnetic nanocatalyst for: N-Arylation of imidazole with boronic acid
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N-Arylation of imidazole was carried out with various arylboronic acids on iron oxide encapsulated by copper-Apatite (Fe3O4?Cu-Apatite), producing excellent yields. Firstly, the iron nanoparticles were prepared using a solvothermal m
- Amadine, Othmane,Essamlali, Younes,Amedlous, Abdallah,Zahouily, Mohamed
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p. 36471 - 36478
(2019/11/20)
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- Ligand complex of copper (II) supported on superparamagnetic Fe3O4?SiO2 nanoparticles: an efficient and magnetically separable catalyst for N-arylation of nitrogen-containing heterocycles with aryl halides
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In this study, we introduce the ligand complex of copper (II) supported on superparamagnetic Fe3O4?SiO2 nanoparticles as a highly intriguing magnetic catalyst in N-arylation of nitrogen heterocycles with aryl halides. The present methodology offers several advantages such as; low catalyst loading, the use of magnetically recoverable and reusable catalyst, high to excellent yields without using any external ligands or additives, short reaction times and simplicity of operation. Also, the magnetic catalyst could be easily separated from the final product by an external magnet and reused up to seven times without any significant loss of activity. Therefore, this separation strategy with negligible leaching makes Fe3O4?SiO2/ligand/Cu(II) an economical catalyst to perform this transformation.
- Zahmatkesh, Saeed,Esmaeilpour, Mohsen,Mollaiy Poli, Azade
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p. 323 - 334
(2019/11/05)
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- Nickel-catalyzed decarbonylation of: N -acylated N-heteroarenes
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Nickel-catalyzed decarbonylation of N-acylated N-heteroarenes is developed. This method can be used to produce a variety of N-aryl heteroarenes, including pyrroles, indoles, carbazoles and phenoxazines, using benzoic acid derivatives as arylating reagents. Arylnickelamide intermediates that are relevant to the catalytic reaction were characterized by X-ray crystallography. When N-acylated benzimidazoles are used as substrates, decarbonylation accompanied 1,2-migration to form 2-arylated benzimidazoles.
- Morioka, Toshifumi,Nakatani, Syun,Sakamoto, Yuki,Kodama, Takuya,Ogoshi, Sensuke,Chatani, Naoto,Tobisu, Mamoru
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p. 6666 - 6671
(2019/07/17)
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- Copper-Catalyzed Decarboxylative N -Arylation of Indole-2-carboxylic Acids
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A novel decarboxylative N -arylation of indole-2-carboxylic acids with aryl halides is developed. The reaction proceeds efficiently in the presence of Cu 2 O as the catalyst to give the corresponding N -aryl indoles in high yields. This synthet
- Zhang, Yan,Hu, Zhe-Yao,Li, Xin-Chang,Guo, Xun-Xiang
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p. 1803 - 1808
(2019/04/05)
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- Preparation method of diarylamine compound
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The invention relates to a preparation method of a diarylamine compound. Specifically, under the catalysis of cuprous oxide supported by chitosan, the arylation reaction used for a nitrogen-containingheterocyclic compound is achieved, and the corresponding diarylamine compound is obtained. The preparation method of the diarylamine compound has the advantages that the process conditions are simple, the yield is good, the operability is strong, and the functional group tolerance is wide.
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Paragraph 0070; 0071; 0072
(2019/04/26)
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- Tryptamine Synthesis by Iron Porphyrin Catalyzed C?H Functionalization of Indoles with Diazoacetonitrile
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The functionalization of C?H bonds with non-precious metal catalysts is an important research area for the development of efficient and sustainable processes. Herein, we describe the development of iron porphyrin catalyzed reactions of diazoacetonitrile with N-heterocycles yielding important precursors of tryptamines, along with experimental mechanistic studies and proof-of-concept studies of an enzymatic process with YfeX enzyme. By using readily available FeTPPCl, we achieved the highly efficient C?H functionalization of indole and indazole heterocycles. These transformations feature mild reaction conditions, excellent yields with broad functional group tolerance, can be conducted on gram scale, and thus provide a unique streamlined access to tryptamines.
- Hock, Katharina J.,Knorrscheidt, Anja,Hommelsheim, Renè,Ho, Junming,Weissenborn, Martin J.,Koenigs, Rene M.
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supporting information
p. 3630 - 3634
(2019/02/13)
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- Dendrimer-encapsulated Cu(Π) nanoparticles immobilized on superparamagnetic Fe3O4@SiO2 nanoparticles as a novel recyclable catalyst for N-arylation of nitrogen heterocycles and green synthesis of 5-substituted 1H-tetrazoles
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In this study, dendrimer-encapsulated Cu(Π) nanoparticles immobilized on superparamagnetic Fe3O4@SiO2 nanoparticles were prepared via a multistep-synthesis. Then, the synthesized composite was fully characterized by various techniques such as fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS), UV-vis spectroscopy, energy dispersive X-ray analysis (EDX), thermogravimetric analysis (TGA) and vibration sample magnetometer (VSM). From the information gained by. FE-SEM and TEM studies it can be inferred that the particles are mostly spherical in shape and have an average size of 50?nm. Also, the amount of Cu is determined to be 0.51?mmol/g in the catalyst by inductively coupled plasma (ICP) analyzer. This magnetic nano-compound has been successfully applied as a highly efficient, magnetically recoverable and stable catalyst for N-arylation of nitrogen heterocycles with aryl halides (I, Br) and arylboronic acids without using external ligands or additives. The catalyst was also employed in a one-pot, three-component reaction for the efficient and green synthesis of 5-substituted 1H-tetrazoles using various aldehydes, hydroxylamine hydrochloride and sodium azide in water. The magnetic catalyst can be easily separated by an external magnet bar and is recycled seven times without significant loss of its activity.
- Esmaeilpour, Mohsen,Sardarian, Ali Reza,Firouzabadi, Habib
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- A waste-minimized protocol for copper-catalyzed Ullmann-type reaction in a biomass derived furfuryl alcohol/water azeotrope
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We report the use of biomass-derived furfuryl alcohol as an effective bidentate ligand able to promote the Ullmann-type copper-catalyzed coupling of aryl halides with heteroaromatic or aliphatic amines. Furfuryl alcohol (FA) can be mixed with water to form the corresponding azeotrope (20 wt% of FA) and therefore can be easily recovered and reused. This protocol is efficiently applied to substrates with various electronic nature and affords the expected products (27 examples) in generally good to excellent yields. It has also been demonstrated that the protocol is both chemically and environmentally effective as the azeotropic mixture can be easily and almost quantitatively recovered at the end of the process.
- Ferlin, Francesco,Trombettoni, Valeria,Luciani, Lorenzo,Fusi, Soliver,Piermatti, Oriana,Santoro, Stefano,Vaccaro, Luigi
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supporting information
p. 1634 - 1639
(2018/04/12)
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- Ultrafine hybrid Cu2O-Fe2O3 nanoparticles stabilized by hexaphenylbenzene-based supramolecular assemblies: A photocatalytic system for the Ullmann-Goldberg coupling reaction
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Ultrafine hybrid Cu2O-Fe2O3 NPs have been prepared using the supramolecular assemblies of hexaphenylbenzene (HPB) derivative 3 as nanoreactors and stabilizers. The as-prepared hybrid Cu2O-Fe2O3 NPs serve as an efficient and recyclable photocatalytic system for carrying out C-N coupling between aryl halides and various amines (aliphatic, aromatic and N-heterocyclic) at room temperature in mixed aqueous media under visible light irradiation. Amazingly, Cu2O-Fe2O3 NPs also exhibited high efficiency in the reactions involving the synthesis of biologically important N-substituted carbazole derivatives. The work being presented in this article demonstrates the preparation of a 'dip strip' coated with the as-prepared catalytic system and utilization of this paper strip as a recyclable and portable heterocatalytic system for carrying out the Ullmann-Goldberg coupling.
- Singh, Gurpreet,Kumar, Manoj,Bhalla, Vandana
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p. 5346 - 5357
(2018/12/05)
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- Unique CuI-pyridine based ligands catalytic systems for N-arylation of indoles and other heterocycles
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Two pyridine-based ligands (N-((pyridin-2-yl) methyl) pyridin-2-amine) L1 and (N-((pyridin-2-yl) methylene) pyridin-2-amine) L2 are explored in present work which are inexpensive, effective and environmentally benign in their properties. These have been utilized for C-N cross coupling reaction resulting in N-arylation. The N-arylation of indole, imidazole and triazole have been successfully carried out with different aryl and heteroaryl halides using these ligands.
- Taywade, Amol,Chavan, Snehal,Ulhe, Avinash,Berad, Baliram
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supporting information
p. 1443 - 1453
(2018/06/01)
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- Palladium-catalyzed direct C3-selective arylation of n-unsubstituted indoles with aryl chlorides and triflates
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The direct C3-arylation of N-unsubstituted indoles with aryl chlorides and triflates has been realized using a palladium-dihydroxyterphenylphosphine (DHTP) catalyst. The site selectivity is different from that obtained with other structurally related ligands. This unique feature of the DHTP ligand is attributed to complex formation between the lithium salts of the ligand and the indole. The method was applied to the late-stage derivatization of pharmaceuticals having a chloro group.
- Yamaguchi, Miyuki,Suzuki, Kohei,Sato, Yusuke,Manabe, Kei
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supporting information
p. 5388 - 5391
(2017/11/07)
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- CuI heterogenized on thiosemicarbazide modified-multi walled carbon nanotubes (thiosemicarbazide-MWCNTs-CuI): Novel heterogeneous and reusable nanocatalyst in the C-N Ullmann coupling reactions
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Herein we described the synthesis of novel thiosemicarbazide-MWCNTs-CuI nanocatalyst by covalent grafting of thiosemicarbazide on carbon nanotubes surface and subsequent coordination with CuI catalyst. The formation of nanocatalyst was analyzed by Raman spectroscopy, energy dispersive spectroscopy (EDS), wavelength-dispersive X-ray spectroscopy (WDX) and ICP analysis. The morphology of the nanocatalyst was characterized using scanning and transmission electron microscopes (SEM and TEM). Additionally, the (thiosemicarbazide-MWCNTs-CuI) nanocatalyst was successfully employed in the N-arylation of indole, amines and imidazoles through intermolecular C(aryl)-N bond formation from the corresponding aryl halides (Ar–I, Ar–Br, Ar–Cl) with amines through Ullmann-type coupling reactions. Interestingly, the novel catalyst could be recovered and recycled five times.
- Veisi, Hojat,Metghalchi, Yalda,Hekmati, Malak,Samadzadeh, Shiva
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- N-Arylation of indole and aniline by a green synthesized CuO nanoparticles mediated by Thymbra spicata leaves extract as a recyclable and heterogeneous nanocatalyst
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In a biological procedure where the aqueous leaves extract of Thymbra spicata was utilized as a reducing and capping agent, copper oxide (CuO) nanoparticles (NPs) were synthesized. These CuO NPs were characterized via Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), wavelength-dispersive X-ray spectroscopy (WDX), and UV–visible spectroscopy. The as prepared nanoparticles have been employed as an appropriate nanocatalyst for ligand-free N-arylation of indole and aniline via Ullmann-type C[sbnd]N coupling reactions. Adequate to outstanding quantities of the N-arylated products were synthesized and the nanocatalyst was retrievable and reusable seven times without noticeable decrease in catalytic performance.
- Veisi, Hojat,Hemmati, Saba,Javaheri, Hadis
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p. 3155 - 3159
(2017/07/18)
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- CopperII phthalocyanine as an efficient and reusable catalyst for the N-arylation of nitrogen containing heterocycles
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Copper phthalocyanine (CuIIPc) was found to be an efficient catalyst for the catalyzed N-arylation of N–H heterocycles with aryl iodides and bromides under mild reaction conditions. A variety of hindered and functionalized N–H heterocycles and aryl halides were successfully used as the substrates for the given catalytic reaction and were transformed in good to excellent yields.
- Yadav, Kumar Karitkey,Narang, Uma,Bhattacharya, Soumee,Chauhan, Shive M.S.
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supporting information
p. 3044 - 3048
(2017/07/17)
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- Highly reusable support-free copper(II) complex of para-hydroxy-substituted salen: Novel, efficient and versatile catalyst for C─N bond forming reactions
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An air-stable, highly active and versatile method for C─N bond forming reactions is reported. Under mild conditions using a highly reusable support-free Cu(II)–salen complex, structurally diverse N-aryl-substituted compounds were obtained via direct C─N bond forming reaction of HN-heterocycles with aryl iodides or three-component C─N bond forming reaction of 2-bromobenzaldehyde, aniline derivatives and sodium azide in good to excellent yields. C─N bond forming reaction for benzimidazole derivatives was also performed in the presence of the catalyst under ambient conditions. A series of hybrid benzimidazoles bearing morpholine, tetrazole and quinoxaline backbones were produced using this method. All reactions were performed in short times under air. The Cu(II) catalyst could be reused up to eight times in the direct cross-coupling reaction of 9H–carbazole with iodobenzene without any decrease in its catalytic activity.
- Sharghi, Hashem,Aberi, Mahdi,Shiri, Pezhman
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- Isocyanide-Induced Activation of Copper Sulfate: Direct Access to Functionalized Heteroarene Sulfonic Esters
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A novel and direct approach to alkyl/aryl heteroarene sulfonic esters using copper sulfate as the environmentally benign inorganic sulfonation reagent was first realized with the aid of isocyanide. A variety of heterocycles reacted to afford the corresponding sulfonic esters through C?H functionalization. In this transformation, the otherwise inert copper sulfate was unusually activated by an isocyanide and employed as the source of the sulfonic substituents in an unprecedented fashion. The findings suggest that an appropriate activator may liberate the chemical activities of some relatively inert inorganic salts for organic synthesis.
- Hong, Xiaohu,Tan, Qitao,Liu, Bingxin,Xu, Bin
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supporting information
p. 3961 - 3965
(2017/03/27)
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- Cu2O/Cs2CO3/DMF: An efficient catalytic system for N-arylation of imidazole with aryl halides under ligand-free conditions
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A ligand-free Cu-catalyzed protocol for the Ullmann-type N-arylation of N-containing heterocycles with aryl or heteroaryl iodides and bromides has been established. A broad range of functional groups is well tolerated on both of the cross-coupling partners, producing the desired products in good to excellent yields.
- Wang, Xiaochuang,Wang, Meiji,Xie, Jianwei
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supporting information
p. 1797 - 1803
(2017/09/22)
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- Gold-catalyzed oxidative couplings of two indoles with one aryldiazo cyanide under oxidant-free conditions
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Gold-catalyzed oxidative couplings of two indoles and one α-cyano gold carbene to form bis(indolyl)methane derivatives are described. Two different indoles are compatible with these reactions to provide reasonable yields. A plausible mechanism is postulated to rationalize the experimental data including product distributions, D2O labeling, and the significant effects of gold catalysts and cyano groups.
- Singh, Rahulkumar Rajmani,Liu, Rai-Shung
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supporting information
p. 4593 - 4596
(2017/04/28)
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- The Catalytic Properties of a Copper-Based Nanoscale Coordination Polymer Fabricated by a Solvent-Etching Top-Down Route
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Manipulating particle size is a powerful means of creating unprecedented applications in both inorganic and organic materials. Coordination polymers, which are emerging as a type of organic–inorganic hybrid materials, have attracted thriving interest in a variety of applications, but nanoscale coordination polymers have scarcely been touched. In this work, the pure-phase {Cu6[1,4-bis(imidazol-1-yl)butane]3I6}∞ coordination polymer with different sizes and morphologies was synthesized for the first time through a facile top-down route assisted by solvent etching. The size and morphology could be adjusted simply by varying the participating etching solvents. Our mechanistic investigations suggest that the bulk coordination polymer as a precursor in the etching solvents may experience a process of dispersion, dissolution, and recrystallization to generate the nanoscale counterpart. High catalytic activity of the nanoscale coordination polymer was observed in the N-arylation of imidazole aryl halides, and this was attributed to a high surface area and a low coordination number of unsaturated coordination sites. This simple and rapid preparation, requiring neither specialized equipment nor harsh conditions, suggests a wealth of potential for reducing the size of coordination polymers to comply with various practical applications.
- Cao, Xiaowei,Fang, Zhenlan,Huang, Wei,Ju, Qiang
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supporting information
p. 4803 - 4807
(2017/11/14)
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- Nickel-catalyzed cross-coupling of aryl or 2-menaphthyl quaternary ammonium triflates with organoaluminum reagents
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The cross-coupling of aryltrimethylammonium triflates with AlMe3 and β-H-containing trialkylaluminums was performed in dioxane at 110 °C under catalysis of (dppp)NiCl2 to afford alkylated arenes. The cross-coupling of 2-menaphthyltri
- He, Fang,Wang, Zhong-Xia
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p. 4450 - 4457
(2017/06/30)
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- Transition-Metal-Free C3 Arylation of Indoles with Aryl Halides
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We report an unprecedented transition metal-free coupling of indoles with aryl halides. The reaction is promoted by KOtBu and is regioselective for C3 over N. The use of degassed solvents devoid of oxygen is necessary for the success of the transformation. Preliminary studies implicate a hybrid mechanism that involves both aryne intermediates and non-propagative radical processes. Electron transfer is also a distinct possibility. These conclusions were substantiated by EPR data, isotopic labeling studies, and the use of radical scavengers and electron transfer inhibitors.
- Chen, Ji,Wu, Jimmy
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supporting information
p. 3951 - 3955
(2017/03/27)
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- A carbon nitride supported copper nanoparticle composite: a heterogeneous catalyst for the N-arylation of hetero-aromatic compounds
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A graphitic carbon nitride supported copper nanoparticle composite (Cu-gCN) has been found to be an active catalyst for the N-arylation of hetero-aromatic systems (pyrrole, pyrazole, and substituted indole) and benzamide molecules, with high product selectivity and good to excellent yields, using substituted aryl bromide as a coupling partner. The intercalated structure and the amine functional group of the carbon nitride prevent the aggregation of the catalytically active copper species during the reaction, and the recyclability study shows the stable performance of the catalyst without a significant loss of catalytic activity.
- Nandi, Debkumar,Siwal, Samarjeet,Mallick, Kaushik
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supporting information
p. 3082 - 3088
(2017/04/14)
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- Immobilized Pd nanoparticles on silica-starch substrate (PNP-SSS): Efficient heterogeneous catalyst in Buchwald–Hartwig C–N cross coupling reaction
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An immobilized Pd nanoparticle on silica-starch substrate (PNP-SSS) is introduced as an efficient heterogeneous catalyst in Pd-catalyzed Buchwald–Hartwig C–N cross coupling reaction. A range of aryl amines were synthesized using reaction of aryl halides (chloride, bromide and iodide) and amines using PNP-SSS catalyst in good to excellent yields. The PNP-SSS catalyst shows high catalytic activity in C-N bond formation reaction and it is reusable in this reaction at least for five times without significant decreasing in its catalytic activity.
- Panahi, Farhad,Daneshgar, Fatemeh,Haghighi, Fatemeh,Khalafi-Nezhad, Ali
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p. 210 - 217
(2017/10/09)
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- Three Different Reactions, One Catalyst: A Cu(I) PNP Pincer Complex as Catalyst for C-C and C-N Cross-Couplings
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An air-stable, thermally robust, and well-defined Cu(I) PNP pincer complex based on the 2,6-diaminopyridine scaffold is described. This complex is an active catalyst for the cross-couplings of a range of aryl and heteroaryl (including benzoxazole, thiazole, pyridine, and thiophene) halides with different organomagnesium reagents, alkynes, and aryl-amines giving excellent to good isolated yields.
- Mastalir, Matthias,Pittenauer, Ernst,St?ger, Berthold,Allmaier, Günter,Kirchner, Karl
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supporting information
p. 2178 - 2181
(2017/04/28)
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- Immobilized Pd(0) nanoparticles on phosphine-functionalized graphene as a highly active catalyst for Heck, Suzuki and N-arylation reactions
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In this study, a phosphine group was chemically grafted to the surface of graphene in order to prepare a reusable ligand with high surface area, incorporating a phosphine moiety. The treatment of graphene oxide (GO) with hydroxide followed by an aqueous work-up yields an OH-functionalized graphene material (GOH) via ring-opening of the epoxide groups. Reaction of GOH with chlorodiphenylphosphine (ClPPh2) gives a new material, GOPPh2 (PFG), which can be used for stabilization of metal nanoparticles or complexation of transition metals in order to prepare a reusable metal catalyst. Stabilization of palladium nanoparticles on the surface of GOPPh2 resulted in the production of an efficient heterogeneous Pd catalyst (PFG-Pd) for application in C-C and C-N bond formation reactions. The PFG-Pd catalyst was characterized using some different microscopic and spectroscopic techniques such as FT-IR, XRD, TEM, SEM, EDX, and ICP analysis. The applicability of the PFG-Pd catalyst was evaluated in Heck, Suzuki and N-arylation reactions. The catalyst system showed high catalyst activity in these processes and the target products were obtained in high isolated yields. The PFG-Pd catalyst was reusable in these reactions for at least 5 times with no significant decrease in its catalytic activity.
- Fareghi-Alamdari, Reza,Haqiqi, Mohsen G.,Zekri, Negar
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p. 1287 - 1296
(2016/02/19)
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- A triazine-phosphite polymeric ligand bearing cage-like P,N-ligation sites: An efficient ligand in the nickel-catalyzed amination of aryl chlorides and phenols
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A novel P,N-ligand was introduced for efficient Ni-catalyzed amination of aryl chlorides. Reaction of cyanuric acid (1,3,5-triazine-2,4,6-triol) and trichlorophosphine (PCl3) resulted in the production of a new porous material (TPPM) containing triazine rings with phosphite moieties in a sheet morphology. Cavities in the prepared compound create sites on the surface of the material with appropriate ligation character to coordinate with metals for catalytic purposes. The nickel-catalyzed amination of aryl chlorides and of phenols in their 2,4,6-triaryloxy-1,3,5-triazine (TAT) protected form were efficiently accomplished in the presence of this easily prepared and reusable P,N-ligand under mild reaction conditions. More importantly, TPPM was reusable for 5 iterations following this protocol without significantly decreasing in its activity.
- Panahi, Farhad,Roozbin, Fatemeh,Rahimi, Sajjad,Moayyed, Mohammadesmaeil,Valaei, Aria,Iranpoor, Nasser
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supporting information
p. 80670 - 80678
(2016/10/12)
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- Efficient and recyclable copper-based MOF-catalyzed N-arylation of N-containing heterocycles with aryliodides
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Copper-based MOF-199 was used as an efficient heterogeneous catalyst to catalyze cross-coupling reactions between N-containing heterocycles and aryliodides with high yields. The catalyst can be easily separated from the reaction mixture, and can be reused at least 5 times without significantly decreasing the activity. The XRD results showed that the crystallinity and structure of MOF-199 can be maintained well during the coupling reaction.
- Li, Zihao,Meng, Fei,Zhang, Jie,Xie, Jianwei,Dai, Bin
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supporting information
p. 10861 - 10865
(2016/12/06)
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- 1,4-Dihydroxyanthraquinone-copper(II) supported on superparamagnetic Fe3O4@SiO2: An efficient catalyst for N -arylation of nitrogen heterocycles and alkylamines with aryl halides and click synthesis of 1-aryl-1,2,3-triazole derivatives
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1,4-Dihydroxyanthraquinone-copper(ii) supported on a superparamagnetic Fe3O4@SiO2 catalyst was employed for the N-arylation of nitrogen heterocycles and alkylamines with aryl halides to afford the corresponding coupled products in good to excellent yields without using external ligands or additives as promoters. Also, we have reported this recyclable catalytic system for efficient synthesis of 1-aryl-1,2,3-triazole derivatives in excellent yields. The desired triazoles were obtained from the reaction of the corresponding aryl boronic acid derivatives, alkyne, NaN3, and 0.5 mol% catalyst in water/acetonitrile as the solvent at room temperature without the additional use of an external reducing agent. These methods show notable advantages such as the heterogeneous nature of the catalyst, low catalyst loading, easy preparation, excellent yields, short reaction times and simplicity of operation. Also, the catalyst can be separated from the reaction mixture by applying a permanent magnet externally and can be reused in six consecutive reaction cycles without significant loss of activity.
- Zahmatkesh, Saeed,Esmaeilpour, Mohsen,Javidi, Jaber
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p. 90154 - 90164
(2016/10/09)
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- Pd immobilized on modified magnetic Fe3O4 nanoparticles: Magnetically recoverable and reusable Pd nanocatalyst for Suzuki-Miyaura coupling reactions and Ullmann-type N-arylation of indoles
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The Pd supported on amidoxime (AO)-functionalized Fe3O4 (Fe3O4/AO/Pd) hybrid material was used as an effective and recyclable nanocatalyst in Suzuki-Miyaura coupling reactions. The catalyst was very effective for the Suzuki-Miyaura reaction of aryl halides (Ar–I, Ar–Br, Ar–Cl) with phenylboronic acid and conversion was excellent in most cases. The yields of the products were in the range from 7–98%. The catalyst showed good stability and could be recovered and reused for six reaction cycles without a significant loss in its catalytic activity. Also, a wide range of N-arylated indoles are selectively synthesized through intermolecular C(aryl)–N bond formation from the corresponding aryl iodides and indoles through Ullmann-type coupling reactions in the presence of the prepared catalyst. [Figure not available: see fulltext.]
- Ghorbani-Vaghei, Ramin,Hemmati, Saba,Hekmati, Malak
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p. 1157 - 1162
(2016/07/15)
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- N-Picolinamides as ligands for Ullmann-type C-N coupling reactions
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The use of N-phenyl-2-pyridincarboxamide-1-oxide as a ligand with Cu2O in Ullmann type C-N bond formations between aryl halides and N-heteroaryls in common solvents, such as MeCN, DMF, and DMSO at 82-120 °C has been successfully demonstrated. The ligand is effective when only 4% equiv is used relative to the substrate. The reaction provided the corresponding products in coupling of electron-rich, electron poor, and ortho-substituted aryl halides, including ortho aryl-chlorides, in good to very good yields. N-arylation is selectively preferred at the benzyl position when ortho-halide benzyl bromide is reacted with one equivalent of pyrazole. However, di-N-arylation is achieved in very high yields when 2.5 equiv of pyrazole is used, providing a stoichiometric control over the coupling reaction.
- Damkaci, Fehmi,Alawaed, Abdulkhaliq,Vik, Erik
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supporting information
p. 2197 - 2200
(2016/05/02)
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- C-N coupling of indoles and carbazoles with aromatic chlorides catalyzed by a single-component NHC-nickel(0) precursor
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A new and efficient nickel-based protocol for the N-arylation of indoles and carbazoles with aromatic chlorides, the least expensive of the aryl halides, is described. The procedure provides selectively N-(hetero)arylation products in good to high yields, in short reaction times and without adding an excess of ligands.
- Rull, Silvia G.,Blandez, Juan F.,Fructos, Manuel R.,Belderrain, Tomás R.,Nicasio, M. Carmen
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supporting information
p. 907 - 911
(2015/03/30)
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- Palladium nanoparticles supported on modified single-walled carbon nanotubes: A heterogeneous and reusable catalyst in the Ullmann-type N-arylation of imidazoles and indoles
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Air- and moisture-stable and recyclable palladium nanoparticles supported on modified single-walled carbon nanotubes (SWCNT-Met/Pd) behave as very efficient heterogeneous catalysts in the Ullmann coupling of imidazoles and indoles with aryl iodides to afford the corresponding C-N coupling reactions under aerobic conditions. These cross coupled products were produced in excellent yields at low palladium loading (~0.2 mol%) and the heterogeneous catalyst can be readily recovered by simple filtration and reused five times without a noticeable loss in its catalytic activity.
- Veisi, Hojat,Morakabati, Nekoo
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p. 2901 - 2907
(2015/04/14)
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- SBA-15-functionalized melamine-pyridine group-supported palladium(0) as an efficient heterogeneous and recyclable nanocatalyst for N-arylation of indoles through Ullmann-type coupling reactions
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SBA-15-functionalized melamine-pyridine group-supported palladium(0) was found to serve as a heterogeneous and recyclable nanocatalyst for N-arylation of indoles with aryl iodides under a low catalyst loading (0.3mol% of Pd) through Ullmann-type C£N coupling reactions. A variety of aryl iodides could be aminated to provide the N-arylated products in good to excellent yields without the need of an inert atmosphere. Also, this catalyst was found to be an efficient system for the N-arylation of other nitrogen-containing heterocycles with aryl iodides. The heterogeneous palladium catalyst could be recovered by simple filtration of the reaction solution and reused for six cycles without significant loss in its activity.
- Veisi, Hojat,Poor Heravi, Mohammad Reza,Hamelian, Mona
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p. 334 - 337
(2015/04/27)
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- Tamarix gallica leaf extract mediated novel route for green synthesis of CuO nanoparticles and their application for N-arylation of nitrogen-containing heterocycles under ligand-free conditions
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We report the green synthesis of CuO nanoparticles (CuO NPs) using Tamarix gallica leaf extract and their catalytic activity for N-arylation of nitrogen-containing heterocycles with aryl halides under ligand-free conditions. Tamarix gallica leaves are used as a bio-material for the first time as reducing agent. The green synthesized CuO NPs was characterized using the powder XRD, TEM, UV-vis and FT-IR. This method offers several advantages, viz. high yields, simple methodology, recyclability of the catalyst and a simple workup procedure.
- Nasrollahzadeh, Mahmoud,Sajadi, S. Mohammad,Maham, Mehdi
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p. 40628 - 40635
(2015/05/20)
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- 3-(Diphenylphosphino)propanoic acid: An efficient ligand for Cu-catalyzed N-arylations of indoles and aryl amines
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3-(Diphenylphosphino)propanoic acid (L2) was found to be an efficient ligand for the copper-catalyzed N-arylations of indoles and arylamines with aryl iodides, the C-N coupling reactions catalyzed by CuCl/L2 were smoothly carried out in DMSO at 120 °C and give the corresponding products with the yields of 25-98 %.
- Liu,Gu,Liu,Ma,Liu,Xie
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p. 1075 - 1078
(2015/02/05)
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- 2-Phenyl-2-(4-phenyl-1 H-1,2,3-triazol-1-yl)ethanol as an efficient and versatile auxiliary ligand in copper(II)-catalyzed Buchwald-Hartwig and Sharpless-Meldal C-N bond-forming reactions
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A highly active, air-stable, and versatile procedure for Buchwald-Hartwig and Sharpless-Meldal C-N bond formation is reported. Under nearly solvent-free conditions using copper(II) acetate and 2-phenyl-2-(4-phenyl-1H-1,2,3-triazol-1-yl)ethanol, a variety of N-heterocycles and various cyclic and noncyclic secondary amines were arylated to form N-aryl compounds in moderate to excellent yields. This methodology also provides rapid access to diverse 1,4-disubstituted 1,2,3-triazoles in good to excellent yields. All reactions are performed in short times under air.
- Sharghi, Hashem,Shiri, Pezhman
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p. 1131 - 1146
(2015/04/14)
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