- Synthesis, structures and catalytic activities of half-sandwich ruthenium complexes based on Schiff Base ligands
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A series of half-sandwich ruthenium(II) complexes containing Schiff-base ligands [Ru(p-cymene)LCl] [HL = (E)-4-X-2-((phenylimino)methyl)phenol, X = H (2a); X = CH3 (2b); X = Cl (2c) and X = Br (2d)] have been synthesized and fully characterized by 1H and 13C NMR spectra, elemental analyses and infrared spectrometry. Moreover, the molecular structures of ruthenium complexes 2b and 2c were confirmed by single-crystal X-ray diffraction methods. These half-sandwich ruthenium complexes are highly catalyzed hydrogenation of nitroarenes to aromatic anilines to proceed in the presence of sodium borohydride reducing agent in ethanol solvent. Notably, complex 2c was found to be a very efficient catalyst toward reduction of nitroarene compounds with wide functional group compatibility and substrate scope.
- Jia, Wei-Guo,Zhang, Hui,Zhang, Tai,Ling, Shuo
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- Novel conversion of 3-(α-hydroxybenzyl)flavones to 3-benzoylchromones and 3-cyanoflavones with NaN3/TFA
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On treatment with NaN3/TFA, 3-(α-hydroxybenzyl)flavones are converted to 3-benzoylchromones and 3-cyanoflavones, plausible mechanisms for which have been suggested. (C) 2000 Elsevier Science Ltd.
- Mallik, Asok K.,Chattopadhyay, Falguni,Dey, Sankar P.
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- Sonication and Microwave-Assisted Primary Amination of Potassium- Aryltrifluoroborates and Phenylboronic Acids under Metal-Free Conditions
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The transition-metal-free generation of a series of primary arylamines from potassium aryltrifluoroborates and phenylboronic acids- is reported. The method uses a mild, inexpensive source of nitrogen (hydroxylamine-O-sulfonic acid) in cooperation with aqueous sodium hydroxide in acetonitrile. Both a sonication and a microwave-assisted method were developed, which are capable of converting ArBF3K functionalities into primary arylamines (ArNH2) in isolated yields of up to 78% (10 examples for each method). This report represents the first general method for the conversion of aryltrifluoroborates into primary arylamines under mild, transition-metal-free conditions in moderate to very good yields. The method is applicable to a wide array of substrates containing electron-donating, electron-neutral, or electron-withdrawing substituents. Both the sonication and microwave methods were also applied to the generation of anilines from phenylboronic acids in isolated yields of up to 96% (12 examples for each method) that were superior to existing room temperature methods in terms of yield, while also offering much shorter reaction times (15 min vs 16 h). In particular, the microwave method is the first to allow for the conversion of arylboronic acids containing strongly electron-withdrawing substituents into the corresponding anilines in good yields, along with electron-donating- substituents in very good to excellent yields.
- Kuik, Dale,McCubbin, J. Adam,Tranmer, Geoffrey K.
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- Selective Reduction of Nitroarenes Catalyzed by Sustainable and Reusable DNA-supported Nickel Nanoparticles in Water at Room Temperature
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Abstract: In this research, a novel, biodegradable and environmentally friendly catalyst composed of nickel nanoparticles supported on DNA was prepared and fully characterized by Fourier transform infrared spectroscopy, high resolution transmission electron microscopy, energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, UV–vis spectroscopy, inductively coupled plasma optical emission spectroscopy, and elemental analysis. The catalyst exhibited remarkable catalytic activity and chemoselectivity for the reduction of various substituted nitroarenes with sodium borohydride (NaBH4) as the source of inexpensive hydride in water at room temperature. High turnover frequency and selectivity were observed for the reduction of all tested substrates. Interestingly, the catalyst could be recovered conveniently for multiple recycling reactions with sustained activity. Furthermore, nearly no nickel species was leached out from the catalyst during the course of reaction, proving the true heterogeneity in the present catalytic protocol. Graphical Abstract: The reduction of various nitroaromatic compounds into their corresponding amines is achieved by DNA supported nickel nanoparticles with the sodium borohydride as the reducing agent in water at room temperature. [Figure not available: see fulltext.].
- Niakan, Mahsa,Asadi, Zahra
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- Atomically dispersed Ni as the active site towards selective hydrogenation of nitroarenes
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Rational design of heterogeneous non-noble metal catalysts as highly efficient and selective catalysts for hydrogenation of nitroarenes with hydrogen as the reducing agent is currently a great challenge, which has attracted a great deal of attention. Herein, a new strategy for achieving atomic dispersion of Ni atoms on nitrogen-doped porous carbon (Ni-N-C) with a specific surface area of up to 810 m2 g-1 and nickel loading as high as 4.4 wt% is developed, yielding high activity, chemoselectivity, and reusability of catalysts in the hydrogenation of nitroarenes using hydrogen as the reductant with a turnover of number (TON) value of 84 and a turnover of frequency (TOF) value of 8.4 h-1 for the first time. The Ni single atoms anchored on N-doped porous carbon by binding with nitrogen/carbon have been proved to be the active sites. Importantly, the Ni-N3 active species is found to contribute more activity compared with Ni-N2 and Ni-N4. Density functional theory (DFT) calculations also reveal that the Ni-N3 structure exhibits the highest activity according to the lowest adsorption energy and the longest elongation N-O bonds of nitrobenzene, which originated from the induced charge transfer. This work opens a new route for rational design and accurate modulation of nanostructured organic molecular transformation catalysts at the atomic scale.
- Yang, Fan,Wang, Minjian,Liu, Wei,Yang, Bin,Wang, Ying,Luo, Jun,Tang, Yushu,Hou, Liqiang,Li, Yun,Li, Zihui,Zhang, Bing,Yang, Wang,Li, Yongfeng
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- A new linker for anchoring/masking primary amines on solid support
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(Chemical Equation Presented) A polymer-supported diketone was synthesized and used to fully protect/mask primary amines by the formation of a pyrrole ring. Various reactions can be performed on this system which then can be cleaved with full restoration of the amine functionality. The resin can also be recycled at least once without loss of purity of the final compound.
- Paladino, Antonietta,Mugnaini, Claudia,Botta, Maurizio,Corelli, Federico
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- Controllable Synthesis of Mesoporous Iron Oxide Nanoparticle Assemblies for Chemoselective Catalytic Reduction of Nitroarenes
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Iron(III) oxide is a low-cost material with applications ranging from electronics to magnetism, and catalysis. Recent efforts have targeted new nanostructured forms of Fe2O3 with high surface area-to-volume ratio and large pore volume. Herein, the synthesis of 3D mesoporous networks consisting of 4-5 nm γ-Fe2O3 nanoparticles by a polymer-assisted aggregating self-assembly method is reported. Iron oxide assemblies obtained from the hybrid networks after heat treatment have an open-pore structure with high surface area (up to 167 m2 g-1) and uniform pores (ca. 6.3 nm). The constituent iron oxide nanocrystals can undergo controllable phase transition from γ-Fe2O3 to α-Fe2O3 and to Fe3O4 under different annealing conditions while maintaining the 3D structure and open porosity. These new ensemble structures exhibit high catalytic activity and stability for the selective reduction of aryl and alkyl nitro compounds to the corresponding aryl amines and oximes, even in large-scale synthesis.
- Papadas, Ioannis T.,Fountoulaki, Stella,Lykakis, Ioannis N.,Armatas, Gerasimos S.
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- Electrophilic amination of aromatics with sodium azide in BF3-H2O
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Boron trifluoride monohydrate is an excellent Br?nsted acid catalyst system for a wide range of reactions. It is a non-oxidizing acid catalyst prepared easily by bubbling BF3 into water. We have found boron trifluoride monohydrate/sodium azide combination to be an efficient reagent system for aromatic electrophilic amination. The present method avoids the use of expensive superacids such as trifluoromethanesulfonic acid and provides a facile access to aromatic amines directly from aromatics.
- Prakash, G.K. Surya,Gurung, Laxman,Marinez, Eric R.,Mathew, Thomas,Olah, George A.
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- Redox and acidity properties of 4-substituted aniline radical cations in water
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By means of pulse radiolysis the one-electron reduction potentials of twelve 4-substituted aniline radical cations and the pKa values of eight 4-substituted aniline radical cations have been determined. Both the potentials and the pKa values were shown to be linearly dependent on the Brown σp+ values for the 4-substituents. The one-electron reduction potentials were also compared to previously reported electrochemically determined E1/2 values resulting in good agreement between the two sets of data. By combining the one-electron reduction potentials and the pKa values the N-H bond dissociation energies of some 4-substituted anilines were calculated, also showing a linear substituent dependence. The absolute N-H bond dissociation energy of aniline found was close to a previously reported value.
- Jonsson, Mats,Lind, Johan,Eriksen, Trygve E.,Merényi, Gábor
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- Regio- and chemoselective catalytic transfer hydrogenation of aromatic nitro and carbonyl as well as reductive cleavage of azo compounds over novel mesoporous NiMCM-41 molecular sieves
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(equation presented) Regio-and chemoselective reduction of nitroarenes and carbonyl compounds and reductive cleavage of azo compounds, including bulkier molecules, was achieved by the catalytic transfer hydrogenation method (CTH) using a novel nickel-containing mesoporous silicate (NiMCM-41) molecular sieve catalyst. In addition, the catalyst was also found to behave as a truly heterogeneous catalyst as the yield was practically unaffected.
- Mohapatra, Susanta K.,Sonavane, Sachin U.,Jayaram, Radha V.,Selvam, Parasuraman
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- Palladium-catalyzed simple and efficient hydrogenative cleavage of azo compounds using recyclable polymer-supported formate
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Palladium-catalyzed room temperature transfer hydrogenation of azo compounds using recyclable polymer-supported formate as the hydrogen donor produces corresponding amine(s) in excellent yields (88%-98%). This method was found to be highly facile with selectivity over a number of other functional groups such as halogen, alkene, nitrile, carbonyl, amide, methoxy, and hydroxyl.
- Abiraj, Keelara,Srinivasa, Gejjalagere R.,Gowda, D. Channe
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- Cobalt-modified molybdenum carbide as an efficient catalyst for chemoselective reduction of aromatic nitro compounds
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This work presents a facile and clean transformation for synthesizing diverse functionalized arylamines through chemoselective reduction reaction of their corresponding substituted nitroarenes catalyzed by the supported cobalt-promoted molybdenum carbide catalyst on modified activated carbon (Co-Mo2C/AC, AC is denoted as the modified activated carbon by H 2O2 oxidation treatment). Various characterization techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma (ICP) and H2 temperature-programmed reduction (H2-TPR) were employed to reveal the relationship between catalyst nature and catalytic performance, and the plausible reaction mechanism is also proposed. The characterization results suggest that the addition of a small amount of transition metals, especially cobalt could significantly promote the formation of a perfect molybdenum carbide crystal phase, resulting in the improvement in catalytic properties of the supported molybdenum carbide catalyst. Reaction results demonstrate that the optimized Co-Mo2C/AC catalyst shows comparable catalytic performance towards precious metals for chemoselective reduction of various aromatic nitro compounds, affording 100% yield for all substrates involved in this work (99.3% of isolated yield for model substrate). Moreover, it can be found that the catalyst could be easily recovered by filtration and recycled without obvious loss in its catalytic properties. Therefore, the developed Co-Mo2C/AC catalyst in this work can be considered as an industrially viable and cheap candidate for clean and highly-efficient production of diverse functionalized arylamines.
- Zhao, Zhongkui,Yang, Hongling,Li, Yu,Guo, Xinwen
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- Combined catalytic system of scandium triflate and boronic ester for amide bond cleavage
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We have found that the combination of scandium with boronic ester enables the cleavage of amide bonds. Primary amides were converted to the corresponding esters in the presence of catalytic amounts of scandium triflate and boronic ester under mild and neutral conditions. This unique catalytic system can be applied to the deprotection of acetylaniline derivatives. In addition, control NMR experiments were carried out to examine the effect of the boronic esters. Copyright
- Kita, Yusuke,Nishii, Yuji,Onoue, Akihiro,Mashima, Kazushi
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- Onium Ions. 26. Aminodiazonium Ions: Preparation, 1H, 13C, and 15N NMR Structural Studies, and Electrophilic Amination of Aromatics
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Protonation of hydrazoic acid and alkyl azides with FSO3/SbF5, HF/SbF5, or HF/BF3 results in the formation of stable aminodiazonium ions as shown by 1H, 13C, and 15N NMR spectroscopic studies.Molecular orbital calculations of the thermodynamics of the protonation of hydrazoic acid also support preferential formation of the aminodiazonium ion.The aminodiazonium ion was also prepared in situ from NaN3/AlCl3/HCl or (CH3)3SiN3/AlCl3/HCl .Aminodiazonium salts were found to affect electrophilic amination of aromatics in high yields, with generally high regioselectivity and low substrate selectivity.
- Mertens, Alfred,Lammerstma, Koop,Arvanaghi, Massoud,Olah, George A.
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- A novel and efficient production of amines from azides using LiCl/NaBH4
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A practical and efficient reagent system LiCl/NaBH4 is used for the production of amines from azides is described.
- Raja Ram,Purushothama Chary,Iyengar
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- Synthesis of ruthenium/reduced graphene oxide composites and application for the selective hydrogenation of halonitroaromatics
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Reduced graphene oxide (RGO) supported ruthenium (Ru) catalyst was prepared by an impregnation method using RuCl3 as a precursor and RGO as a support. The catalyst Ru/RGO was used for the selective hydrogenation of p-chloronitrobenzene (p-CNB)
- Fan, Guang-Yin,Huang, Wen-Jun
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- Electrophilic Amination of Higher Order Cuprates with N,O-Bis(trimethylsilyl)hydroxylamine
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In the reaction of higher order cyanocuprates with N,O-bis(trimethylsilyl)hydroxylamine delivery of the NHSiMe3 moiety to one of the anionic ligands in the cuprate takes place even in the absence of external bases according to an "electrophilic amination" protocol.Details of the methodology are given, and the reaction mechanism is analyzed in terms of interception by a mixed bis-metal cluster of a lithium N-silyl-N-siloxyamide, followed by intramolecular C-N coupling.This method is applicable to cyanocuprates bearing aromatic, heteroaromatic, and saturated aliphatic ligands.A number of 2-amino-substituted heterocycles, not easily accesible by normal routes, can be obtained with the aid of a stabilizing silylation at the nitrogen atom.
- Casarini, Antonella,Dembech, Pasquale,Lazzari, Dario,Marini, Elisabetta,Reginato, Gianna,et al.
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- Palladium-modified functionalized cyclodextrin as an efficient and recyclable catalyst for reduction of nitroarenes
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A palladium-modified functionalized cyclodextrin (DACH-Pd-β-CD) catalytic system was synthesized and characterised. It showed high catalytic performance in the reduction of different nitroarenes to the corresponding anilines with the presence of sodium borohydride in water at room temperature. The yields of the desired products are up to 99%. Furthermore, the catalyst can be easily separated and still could maintain high catalytic activity after five cycles and no leaching of Pd into solution occurred.
- Guo, Yafei,Li, Jiuling,Zhao, Fen,Lan, Guineng,Li, Liang,Liu, Yuqi,Si, Yunsen,Jiang, Yubo,Yang, Bo,Yang, Rui
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- An ammonia equivalent for the palladium-catalyzed amination of aryl halides and triflates
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Commercially available benzophenone imine serves as a convenient ammonia equivalent in the palladium-catalyzed amination of aryl halides and triflates. The benzophenone imine adducts can be cleaved directly to the corresponding primary anilines by catalytic hydrogenation or treatment with hydroxylamine hydrochloride or a catalytic amount of HCl in wet THF.
- Wolfe, John P.,Ahman, Jens,Sadighi, Joseph P.,Singer, Robert A.,Buchwald, Stephen L.
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- Highly dispersed Pt in MIL-101: An efficient catalyst for the hydrogenation of nitroarenes
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Homogeneously dispersed Pt adatoms were fabricated in ordered mesoporous metal-organic framework (MIL-101) through a simple colloid method. N 2-adsorpton and time-resolved HRTEM analysis disclosed that Pt dispersed highly in the pores and/or ou
- Du, Weichen,Chen, Gongzhou,Nie, Renfeng,Li, Yingwei,Hou, Zhaoyin
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- Photochemical Beckmann Rearrangements. Correspondence between Substituent Effect in Oximes and Oxaziridines
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The relative migratory tendencies of hydrogen and aryl groups in the photochemical Beckmann rearrangement of benzaldoximes 2a-c were compared with those in the photochemical rearrangement of 2-alkyl-3-aryloxaziridines 3a-f.The migratory tendencies depended on the nature of the aryl substituent and were similar in 2a-c and 3a-c, implying that the photochemical Beckmann rearrangement proceeds through an oxaziridine intermediate.A similar order of migratory tendencies was not found in the tert-butyloxaziridines 3d-f, presumably because of steric effects.
- Ogata, Yoshiro,Tagaki, Katsuhiko,Mizuno, Kiyohiko
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- An abnormal N-heterocyclic carbene based nickel complex for catalytic reduction of nitroarenes
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Herein we report the synthesis of a nickel(ii) dichloro complex bearing an abnormal N-heterocyclic carbene (aNHC). The NiCl2(aNHC)2 complex has been used as an efficient catalyst for the reduction of nitroarenes with hydrosilanes to give aromatic amines in good to excellent yields. This catalytic protocol can tolerate functional groups such as halides, alkenes or nitriles. Furthermore, the longevity of the catalyst was tested in successive catalytic cycles, which indicates a sustained catalytic activity over multiple catalytic cycles.
- Vijaykumar, Gonela,Mandal, Swadhin K.
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- Palladium catalyzed activation of borane-amine adducts: Rate enhancement of amine-borane methanolysis in the reduction of nitrobenzenes to anilines
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Hydrolytically stable borane-amines can be activated in situ through palladium catalysis and perform reductions not possible otherwise. Hence, borane-trimethylamine is an efficient hydrogen-transfer reagent for the open vessel reduction of nitroaryls to anilines. Likewise, the palladium catalyzed methanolysis/decomplexation of stable borane-amine adducts is accelerated by the action of nitrobenzene.
- Couturier, Michel,Tucker, John L.,Andresen, Brian M.,Dubé, Pascal,Brenek, Steven J.,Negri, Joanna T.
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- Simple and efficient CuI/PEG-400 system for amination of aryl halides with aqueous ammonia
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The cross-coupling reaction between aryl halides with aqueous ammonia was efficiently catalyzed in CuI/PEG-400 System with high yield. A range of electron-withdrawing or electron-donating aryl iodides and bromides were found to be applicable to the environmentally benign system. The process allows assembly of primary arylamines in great diversity which bear a wide range of functional groups including cyano, nitro, acetyl, ether, or amino moiety.
- Chen, Junmin,Yuan, Tangjun,Hao, Wenyan,Cai, Mingzhong
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- Large-scale preparation of B/N co-doped graphene-like carbon as an efficient metal-free catalyst for the reduction of nitroarenes
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Boron and nitrogen co-doped graphene-like carbon (BNG) is a metal-free catalyst that has been synthesized by combining ball-milling with thermal treatment. Firstly, the edge-selectively-functionalized graphene nanoplatelets (EFGnPs) were prepared by ball
- Yang, Fan,Cao, Yan,Chen, Zhuo,He, Xing,Hou, Liqiang,Li, Yongfeng
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- Synthesis, characterization, and catalytic activity of half-sandwich ruthenium complexes with pyridine/phenylene bridged NHC = E (NHC = N-heterocyclic carbene, E = S, Se) ligands
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Three half-sandwichruthenium(II) complexes with pyridine/phenylene bridged NHC = E (NHC = N-heterocyclic carbene, E = S, Se) ligands [Ru(p-cymene)L](PF6)1–2 (1a–1c, L = ligand) were synthesized and characterized. All ruthenium complexes were fully characterized by 1H and 13C NMR spectra, mass spectrometry, and single-crystalX-ray diffraction methods. Moreover, the half-sandwich ruthenium complexes with NHC = E ligands showed highly catalytic activities towards to the tandem dehydrogenation of ammonia borane (AB) and hydrogenation of R–NO2 to R–NH2 at 353 K in water.
- Jia, Wei-Guo,Du, Teng-Teng,Gao, Li-Li,Du, Jun
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- Accessing Multiple Classes of 2 H-Indazoles: Mechanistic Implications for the Cadogan and Davis-Beirut Reactions
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The Cadogan cyclization is a robust but harsh method for the synthesis of 2H-indazoles, a valuable class of nitrogen heterocycles. Although nitrene generation by exhaustive deoxygenation is widely accepted as the operating mechanism in the reductive cyclization of nitroaromatics, non-nitrene pathways have only been theorized previously. Here, 2H-indazole N-oxides were synthesized through an interrupted Cadogan/Davis-Beirut reaction and are presented as direct evidence of competent oxygenated intermediates; mechanistic implications for both reactions are discussed. Isolation and characterization of these N-oxides enabled a formal Cadogan cyclization at room temperature for 2H-indazole synthesis.
- Zhu, Jie S.,Li, Clarabella J.,Tsui, Ka Yi,Kraemer, Niklas,Son, Jung-Ho,Haddadin, Makhluf J.,Tantillo, Dean J.,Kurth, Mark J.
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- Manganese Catalyzed Hydrogenation of Azo (N=N) Bonds to Amines
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We report the first example of homogeneously catalyzed hydrogenation of the N=N bond of azo compounds using a complex of an earth-abundant-metal. The hydrogenation reaction is catalyzed by a manganese pincer complex, proceeds under mild conditions, and yields amines, which makes this methodology a sustainable alternative route for the conversion of azo compounds. A plausible mechanism involving metal-ligand cooperation and hydrazine intermediacy is proposed based on mechanistic studies. (Figure presented.).
- Ben-David, Yehoshoa,Das, Uttam Kumar,Diskin-Posner, Yael,Kar, Sayan,Milstein, David
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- Synthesis and Reactions of Trimethylsilylmethyl Azide
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Trimethylsilylmethyl azide, prepared quantitatively from trimethylsilylmethyl chloride and sodium azide, could be used for the amination of aryl Grignard reagents or aryl-lithium compounds.
- Nishiyama, Kozaburo,Tanaka, Nobuko
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- RATES AND MECHANISM OF SOLVOLYSIS OF N-PHENYLCYCLOSILAZOXANES
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The rates of solvolysis of some N-phenyl-1-aza-3,5-dioxa-2,4,6-tris(dimethylsilyl)cyclohexanes, substituted in the benzene ring, have been measured spectrophotometrically in methanol containing a small quantity of water.The reaction is subject to general acid catalysis and is inhibited by weak bases.Electron-donating substituents accelerate the solvolysis.The ρ-constant, derived from the linear relation between the logarithms of the rate constants and Hammett ? constants is -1.2 (ρ = -1.0 in a neutral medium).A reverse deuterium isotope effect has been found(kH/kD = 0.82).The proposed mechanism for the Si-N bond cleavage, and the associated ring-opening, involves simultaneous nucleophilic attack of a solvent molecule on silicon and electrophilic assistance by proton transfer from the catalysing acid to the nitrogen.
- Lasocki, Zygmunt,Witekowa, Malgorzata
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- Sodium hydroxide-catalyzed transfer hydrogenation of carbonyl compounds and nitroarenes using ethanol or isopropanol as both solvent and hydrogen donor
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The development of a clean and renewable energy carrier has become a subject of high priority, and new catalytic system that involves both abundant and cheap catalysts and green solvents is highly desirable in terms of practical and sustainable chemistry. In this spirit, sodium hydroxide-catalyzed transfer hydrogenation of carbonyl compounds using ethanol as both hydrogen source and solvent is developed in this report. The process is successfully utilized in the hydrogenation of various ketones and aldehydes, and the corresponding primary and secondary alcohols are synthesized with excellent conversions. Furthermore, sodium hydroxide also smoothly promotes the transfer hydrogenation of nitroarenes providing anilines and azobenzenes. For both carbonyl compounds and nitroarenes, results in ethanol and isopropanol are compared, and a remarkable change of selectivity between these two solvents is disclosed for the NaOH-catalyzed transfer hydrogenation to nitroarenes.
- Wang, Dong,Deraedt, Christophe,Ruiz, Jaime,Astruc, Didier
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- Urea-based porous organic frameworks: Effective supports for catalysis in neat water
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Two urea-based porous organic frameworks, UOF-1 and UOF-2, were synthesized through a urea-forming condensation of 1,3,5-benzenetriisocyanate with 1,4-diaminobenzene and benzidine, respectively. UOF-1 and UOF-2 possess good hydrophilic properties and high scavenging ability for palladium. Their palladium polymers, PdII/UOF-1 and PdII/UOF-2, exhibit high catalytic activity and selectivity for Suzuki-Miyaura cross-coupling reactions and selective reduction of nitroarenes in water. The catalytic reactions can be efficiently performed at room temperature. Palladium nanoparticles with narrow size distribution were formed after the catalytic reaction and were well dispersed in UOF-1 and UOF-2. XPS analysis confirmed the coordination of the urea oxygen atom with palladium. SEM and TEM images showed that the original network morphology of UOF-1 and UOF-2 was maintained after palladium loading and catalytic reactions. Feeling supportive? Two urea-based porous organic frameworks were prepared by a facile urea-forming condensation and can serve as effective supports in palladium-catalyzed Suzuki-Miyaura cross-coupling reactions and reduction of nitroarenes in water. The reactions can even be efficiently performed at room temperature. The original morphology of the urea-based frameworks was maintained after the catalytic reactions.
- Li, Liuyi,Chen, Zhilin,Zhong, Hong,Wang, Ruihu
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- Conventional and microwave assisted hydrogenolysis using zinc and ammonium formate
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The selective deprotection of several N-Bzl amino derivatives to the corresponding amines and the removal of S-Bzl and O-Bzl groups from the protected amino acids with ammonium formate and commercial zinc dust are reported. Many other reducible or hydrogenolysable substituents such as halogens, methoxy, phenol, ester, acid, ethene, and Boc groups are unaffected.
- Srinivasa,Babu, S. N. Narendra,Lakshmi,Gowda, D. Channe
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- Novel and efficient hydrogenative cleavage of azo compounds to amine(s) using chitosan-supported formate and magnesium
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A convenient and efficient method for the hydrogenative cleavage of azo compounds to corresponding amine (s) using chitosan-supported formate as hydrogen donor in conjunction with low-cost magnesium powder is reported. This method was found to be highly facile with selectivity over several other functional groups, such as halogen, alkene, nitrile, carbonyl, ether, amide, methoxy, and hydroxyl groups. Furthermore, this mild, exceedingly efficient, and highly chemoselective method simplifies the handling and separation procedures. Copyright
- Yu,Ma,Jin,Zhen
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- Eco-friendly hydrogenation of aryl azides to primary amines on graphene oxide-decorated bimetallic Rh-Pt nanoparticles (RhPt@GO NPs)
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Graphene oxide-supported rhodium/platinum (Rh-Pt) nanoparticles (Rh-Pt@GO NPs) are a promising catalyst for the reduction of aryl azides to primary amines. Rh-Pt@GO NPs have been produced by the microwave-assisted sonochemical method. This catalyst showed superior catalytic activity to afford quantitative yields of primary amines under an extremely mild condition in the presence of sodium borohydride. The synthesized novel catalyst was easily recovered by centrifugation and reused without loss of its catalytic activity. The spectroscopic analyses of the RhPt@GO NPs indicated the formation of highly crystalline, monodisperse, and colloidally stable RhPt@GO NPs.
- Kilbas, Benan,Kara, Belguzar Yasemin
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- PdCu nanoparticles supported on graphene: An efficient and recyclable catalyst for reduction of nitroarenes
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Graphene supported PdCu bimetallic nanoparticles were synthesized through coreduction of PdCl2and CuCl2·H2O. X-ray diffraction (XRD), X-ray photoelectron (XPS) and transmission electron microscopy (TEM) were performed to characterize the structures. The complex could be used as an efficient catalyst for reduction of nitroarenes to the corresponding anilines in the presence of NaBH4and recycled up to six runs without significant loss of activity.
- Feng, Yi-Si,Ma, Jing-Jing,Kang, Yu-Mei,Xu, Hua-Jian
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- The Reductive Potential of Dodecacarbonyltri-iron on Basic Alumina
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Dodecacarbonyltri-iron on basic alumina constitutes a simple, mild, and convenient method for reducing nitroarenes to aromatic amines.
- Alper, Howard,Gopal, Madhuban
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- Regioselective Synthesis of 5-Trifluoromethyl Pyrazoles by the [1+4] Cyclization of Phenylhydrazones with N-Aryl Trifluoroacetimidoyl Iodides
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Treatment of the phenylhydrazone of a methyl ketone (2) or cyclohexanone (3) with N-aryl trifluoroacetimidoyl iodide (1) in the presence of excess sodium hydride resulted in a [1+4] cyclization to give 5-trifluoromethyl pyrazoles (4, 5) regioselectively. The structure of products 4 or 5 was confirmed by the 13C NMR spectra.
- Yu, Hong-Bin,Huang, Wei-Yuan
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- Highly active and selective catalysis of bimetallic Rh3Ni 1 nanoparticles in the hydrogenation of nitroarenes
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Because of the requirements of sustainable development as well as the desirability of using molecular hydrogen as a chemical reagent, it is of paramount importance and great challenge to develop highly active and selective catalysts for the hydrogenation
- Cai, Shuangfei,Duan, Haohong,Rong, Hongpan,Wang, Dingsheng,Li, Linsen,He, Wei,Li, Yadong
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- Inhibition of Acid-induced decomposition of diphenyltriazenes by complexation with cyclodextrins
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Acid-promotedN Nbond cleavage in 1,3-diphenyltriazenes (X-Ph-N=N-NH-Ph-X X = H, 4-OCH3), leading to formation of diazonium ions and anilines, is strongly inhibited in aqueous solutions in the presence of cyclodextrins (CDs). The inhibition is ascribed to the formation of inclusion complexes that render the guest diphenyltriazene significantly less basic as a result of the less polar nature of the CD cavity (amicrosolvent effect). Association equilibrium constants for 1:1 host-guest complexes increase in the order α-CD 3 being larger than those for X = H. In the case of α-CD, formation of 2:1 host-guest complexes is also involved.
- Xu, Tingting,Asadi, Atefeh Vaez-Zadeh,Barra, Monica
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- Sustainable Protocol for the Reduction of Nitroarenes by Heterogeneous Au@SBA-15 with NaBH4 under Flow Conditions
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A gold-incorporated SBA-15 catalyst was prepared by a solvent-free ball-milling approach. The catalyst showed high reactivity and selectivity in the reduction of a variety of nitroarenes to anilines operating in absolute EtOH with NaBH4 as reducing agent. The catalyst was reused in batch conditions over five consecutive runs without any losses of activity or selectivity. Considering the high chemical stability and reusability of the catalytic system, a continuous-flow protocol was also investigated and defined to minimize the generation of waste and optimize the continuous reuse of the catalyst. Benefits of flow conditions were proven by turnover numbers that increased from 47.5 to 1902 and also by the minimization of both leaching (9.5 vs. 1 ppm) and E-factor values (8 vs. 23 in batch).
- Ferlin, Francesco,Giannoni, Tommaso,Zuliani, Alessio,Piermatti, Oriana,Luque, Rafael,Vaccaro, Luigi
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- Chemoselective hydrogenation of functionalized nitroarenes and imines by using carbon nanofiber-supported iridium nanoparticles
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The reaction of three types of carbon nanofibers (CNFs; platelet: CNF-P, tubular: CNF-T, herringbone: CNF-H) with Ir4(CO)12 in mesitylene at 165 °C provided the corresponding CNF-supported iridium nanoparticles, Ir/CNFs (Ir content=2.3-2.6 wt. %). Transmission electron microscopy (TEM) studies of these Ir/CNF samples revealed that size-controlled Ir nanoparticles (average particle size of 1.1-1.5 nm) existed on the CNFs. Among the three Ir/CNF samples, Ir/CNF-T showed an excellent catalytic activity and chemoselectivity towards hydrogenation of functionalized nitroarenes and imines; the corresponding aniline derivatives were obtained with high turnover numbers at ambient temperature under 10 atm of H2, and the catalyst is reusable. Ir/CNF-T was also effective for the reductive N-alkylation of anilines with carbonyl compounds.
- Motoyama, Yukihiro,Taguchi, Masahiro,Desmira, Nelfa,Yoon, Seong-Ho,Mochida, Isao,Nagashima, Hideo
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- Electrochemical technique and copper-promoted transformations: Selective hydroxylation and amination of arylboronic acids
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An efficient and selective electrosynthesis of phenols and anilines from arylboronic acids in aqueous ammonia is achieved in an undivided cell. By simply changing the concentration of aqueous ammonia and the anode potential, good yields of phenols and anilines can be obtained chemoselectively with high reaction rates. We propose that anodic oxidation could have played an important role in these transformations.
- Qi, Hong-Lin,Chen, Dong-Song,Ye, Jian-Shan,Huang, Jing-Mei
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- Superior activity and selectivity of heterogenized cobalt catalysts for hydrogenation of nitroarenes
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The development of improved catalysts for highly selective hydrogenation of nitroarenes is described. For this purpose Co nanoparticles were supported on ordered mesoporous carbon CMK-3 and characterized in detail. The optimal CMK-3-CoPc catalyst exhibits excellent hydrogenation activity for several (hetero)aromatic nitro compounds and yielded the corresponding anilines under mild conditions (40 °C, 20 bar H2).
- Li, Wu,Artz, Jens,Broicher, Cornelia,Junge, Kathrin,Hartmann, Heinrich,Besmehn, Astrid,Palkovits, Regina,Beller, Matthias
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- A convenient and general ruthenium-catalyzed transfer hydrogenation of nitro- and azobenzenes
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An easily accessible in situ catalyst composed of [{RuCl 2(p-cymene)}2] and terpyridine has been developed for the selective transfer hydrogenation of aromatic nitro and azo compounds. The procedure is general and the selectivity of the catalyst has been demonstrated by applying a series of structurally diverse nitro and azo compounds (see scheme).
- Jagadeesh, Rajenahally V.,Wienhoefer, Gerrit,Westerhaus, Felix A.,Surkus, Annette-Enrica,Junge, Henrik,Junge, Kathrin,Beller, Matthias
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- Nickel Boride Catalyzed Reductions of Nitro Compounds and Azides: Nanocellulose-Supported Catalysts in Tandem Reactions
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Nickel boride catalyst prepared in situ from NiCl2 and sodium borohydride allowed, in the presence of an aqueous solution of TEMPO-oxidized nanocellulose (0.01 wt%), the reduction of a wide range of nitroarenes and aliphatic nitro compounds. Here we describe how the modified nanocellulose has a stabilizing effect on the catalyst that enables low loading of the nickel salt pre-catalyst. Ni-B prepared in situ from a methanolic solution was also used to develop a greener and facile reduction of organic azides, offering a substantially lowered catalyst loading with respect to reported methods in the literature. Both aromatic and aliphatic azides were reduced, and the protocol is compatible with a one-pot Boc-protection of the obtained amine yielding the corresponding carbamates. Finally, bacterial crystalline nanocellulose was chosen as a support for the Ni-B catalyst to allow an easy recovery step of the catalyst and its recyclability for new reduction cycles.
- Proietti, Giampiero,Prathap, Kaniraj Jeya,Ye, Xinchen,Olsson, Richard T.,Dinér, Peter
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supporting information
p. 133 - 146
(2021/11/04)
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- C-Nitrosothioformamide: A Donor Template for Dual Release of HNO and H2S
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C-Nitrosothioformamide was demonstrated to be a donor template for dual release of HNO and COS triggered by a retro-Diels-Alder reaction. COS is an H2S precursor in the presence of carbonic anhydrase. This process produces HNO and H2S in a slow but steady manner. As such, the direct reaction between HNO and H2S under this situation appears to be minor. This may provide a useful tool for studying the synergistic effects of HNO and H2S.
- Kelly, Shane S.,Ni, Xiang,Radford, Miles N.,Xian, Ming,Yuen, Vivian
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- Chemo-, site-selective reduction of nitroarenes under blue-light, catalyst-free conditions
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The tandem reaction of photoinduced double hydrogen-atom transfer and deoxygenative transborylation for chemo- and site-selective reduction of nitroarenes into aryl amines under catalyst-free, room temperature conditions was disclosed in excellent yields. In this reaction, isopropanol (iPrOH) was used as hydrogen donor and tetrahydroxydiboron [B2(OH)4] as deoxygenative reagent with green, cheap, and commercially available credentials. In particular, a wide range of reducible functional groups such as halogen (-Cl, -Br and even -I), alkenyl, alkynyl, aldehyde, ketone, carboxyl, and cyano are all tolerated. Moreover, the reaction preferentially reduces the nitro group at the electron-deficient site over another nitro group in the same molecule. A detailed mechanistic investigation in combination of experiments and theoretical calculations gave a reasonable explanation for the reaction pathway.
- Liang, Yong,Lu, Changsheng,Lu, Shuo,Ma, Jiawei,Ren, Hongyuan,Wang, Bin,Xu, Jingkai,Yan, Hong
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supporting information
p. 2420 - 2424
(2021/12/13)
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- Rhodium nanoparticles supported on 2-(aminomethyl)phenols-modified Fe3O4 spheres as a magnetically recoverable catalyst for reduction of nitroarenes and the degradation of dyes in water
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A magnetic nanostructured catalyst (Fe3O4@SiO2-Amp-Rh) modified with 2-(aminomethyl)phenols (Amp) was designed and prepared, which is used to catalyze the reduction of aromatic nitro compounds into corresponding amines and the degradation of dyes. The 2-aminomethylphenol motif plays a vital role in the immobilization of rhodium nanoparticles to offer extraordinary stability, which has been characterized by using various techniques, including transmission electron microscopy (TEM), thermal gravimetric analyzer (TGA), X-Ray Diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). A variety of nitroaromatic derivatives have been reduced to the corresponding anilines in water with up to yields of 99% within 1?h at room temperature. In addition, the catalyst system is effective in catalyzing the reduction of toxic pollutant 4-nitrophenol and the degradation of MO, MB and RhB dyes. Importantly, this catalyst Fe3O4@SiO2-Amp-Rh can be easily recovered by an external magnetic field because of the presence of magnetic core of Fe3O4, and the activity of Fe3O4@SiO2-Amp-Rh does not decrease significantly after 7 times’ recycling, which indicates that the catalyst performed high reactivity as well as stability. Graphical abstract: [Figure not available: see fulltext.]
- Chen, Tian,Chen, Zhangpei,Hu, Jianshe,Lv, Kexin,Reheman, Aikebaier,Wang, Gongshu
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- Synthesis and characterization of chitosan pyridyl imine palladium (CPIP) complex as green catalyst for organic transformations
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In this work, the modification of chitosan using 2-acetyl pyridine has been used to prepare an intermediate, chitosan pyridyl imine (CPI), in first step and then in second step it is further reacted with Pd(OAc)2 to develop chitosan pyridyl imine palladium (CPIP) complex catalyst in a very simplistic way. The formed CPIP has been extensively characterized with respect to raw chitosan utilizing methods including FT-IR, pyrolysis GC–MS, XRD, XPS, FE-SEM, EDS, TGA-DTG and DSC. TG-DSC study suggested that the catalyst is thermally stable up to 300?°C. This catalyst shows an excellent activity in the reduction of toxic pollutant nitrobenzene to less toxic aniline. CPIP complex has also been found to give magnificent results in Suzuki–Miyaura and Heck cross-coupling reactions, and therefore, using this green catalyst, the toxic phosphine ligand can be excluded from cross-coupling reactions. This study furnishes an economic and eco-friendly catalyst for organic transformation in sustainable chemistry.
- Chundawat, Narendra Singh,Pathan, Sultan,Singh, Girdhar Pal,Deuri, Arup Saha,Zarrintaj, Payam,Chauhan, Narendra Pal Singh
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p. 2835 - 2850
(2021/02/11)
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- Development and Application of Efficient Ag-based Hydrogenation Catalysts Prepared from Rice Husk Waste
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The development of strategies for the sustainable management and valorization of agricultural waste is of outmost importance. With this in mind, we report the use of rice husk (RH) as feedstock for the preparation of heterogeneous catalysts for hydrogenation reactions. The catalysts were prepared by impregnating the milled RH with a silver nitrate solution followed by carbothermal reduction. The composition and morphology of the prepared catalysts were fully assessed by IR, AAS, ICP-MS, XPS, XRD and STEM techniques. This novel bio-genic silver-based catalysts showed excellent activity and remarkable selectivity in the hydrogenation of nitro groups in both aromatic and aliphatic substrates, even in the presence of reactive functionalities like halogens, carbonyls, borate esters or nitriles. Recycling experiments showed that the catalysts can be easily recovered and reused multiple times without significant drop in performance and without requiring re-activation.
- Unglaube, Felix,Kreyenschulte, Carsten Robert,Mejía, Esteban
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p. 2583 - 2591
(2021/04/09)
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- A novel water-dispersible and magnetically recyclable nickel nanoparticles for the one-pot reduction-Schiff base condensation of nitroarenes in pure water
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In this work, a heterogeneous nanocatalyst called Ni-Fe3O4@Pectin~PPA ~ Piconal was first synthesized, which was investigated as a bifunctional catalyst containing nickel functional groups. On the other hand, this Ni-Fe3O4@Pectin~PPA ~ Piconal catalyst in aqueous solvents shows a very effective performance at ambient temperature for the nitroarene reduction reaction with sodium borohydride, for which NaBH4 is considered as a reducing agent. This is a novelty magnetic catalyst that was approved by various methods, including Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), Dynamic light scattering (DLS), Transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Inductively coupled plasma (ICP), Energy-dispersive X-ray spectroscopy (EDX), and Field emission scanning electron microscopy (FESEM) analyses. From the satisfactory results obtained from the reduction of nitrogen, this catalytic system is used for a one-pot protocol containing a reduction-Schiff base concentration of diverse nitroarenes. It was corroborated with the heterogeneous catalytic experiments on the one-pot tandem synthesis of imines from nitroarenes and aldehydes. Finally, the novel Ni-Fe3O4@Pectin~PPA ~ Piconal catalyst could function as a more economically desirable and environmentally amicable in the catalysis field. The favorable products are acquired in good to high performance in the attendance of Ni-Fe3O4@Pectin~PPA ~ Piconal as a bifunctional catalyst. This catalyst can be recycled up to six steps without losing a sharp drop.
- Ghamari Kargar, Pouya,Ravanjamjah, Asiye,Bagherzade, Ghodsieh
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p. 1916 - 1933
(2021/07/10)
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- UiO-66/btb/Pd as a stable catalyst reduction of 4-nitrophenol into 4-aminophenol
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In order to synthesize highly sparse nanoparticles, UiO-66-NH2 can be utilized as an appropriate support. It has great surface area, which is functionalized by 1,3-bis(dimethylthiocarbamoyloxy)benzene compounds that can act as the powerful performers, hence, the Pd (II) is a complex without aggregate over the UiO-66-NH2 microspheres structures (UiO-66/btb/Pd). Nitro-aromatic pollution in industrial waste streams threat wellbeing of water resources. The produced UiO-66/btb/Pd nanocatalyst showed appropriate catalytic activity for reduce nitro-aromatic compounds in aqueous solution. XRD, EDS, SEM, FT-IR, and TEM were utilized for characterizing the nanostructures UiO-66/btb/Pd.
- Kiani, Zahra,Zhiani, Rahele,Khosroyar, Susan,Motavalizadehkakhky, Alireza,Hosseiny, Malihesadat
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- Rhodium-terpyridine Catalyzed Transfer Hydrogenation of Aromatic Nitro Compounds in Water
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A rhodium terpyridine complex catalyzed transfer hydrogenation of nitroarenes to anilines with i-PrOH as hydrogen source and water as solvent has been developed. The catalytic system can work at a substrate/catalyst (S/C) ratio of 2000, with a turnover frequency (TOF) up to 3360 h?1, which represents one of the most active catalytic transfer hydrogenation systems for nitroarene reduction. The catalytic system is operationally simple and the protocol could be scaled up to 20 gram scale. The water-soluble catalyst bearing a carboxyl group could be recycled 15 times without significant loss of activity.
- Liu, Yuxuan,Miao, Wang,Tang, Weijun,Xue, Dong,Xiao, Jianliang,Wang, Chao,Li, Changzhi
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supporting information
p. 1725 - 1729
(2021/06/01)
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- Room-temperature copper-catalyzed electrophilic amination of arylcadmium iodides with ketoximes
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We started our study by preparation two ketoximes. Later, there were studies to reveal these ketoximes' effects in the electrophilic amination reaction with organocadmium reagents. Primarily, it was observed that arylcadmium iodides could not be reacted with ketoximes at room temperature in the absence of a catalyst. CuCN was a suitable catalyst for this electrophilic amination reaction of arylcadmium iodides and allowed the preparation of functionalized aniline derivatives in good yields under mild reaction conditions. We obtained the results indicated that the yield of primary arylamines was strongly dependent on the steric and electronic effects of organocadmium reagent and amination agent. In the case of both amination reagents, meta-substituted arylamines were obtained in higher yields than para-substituted arylamines. We observed that acetone O-(4-chlorophenylsulfonyl)oxime, 1, as an aminating agent, was more successful than acetone O-(2-Naphthylsulfonyl)oxime, 2, in the synthesis of functionalized arylamines by electrophilic amination of corresponding aryl cadmium iodides. In this method, there is no cadmium release to the environment.
- Korkmaz, Adem
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p. 3119 - 3125
(2021/05/10)
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- High yielding electrophilic amination with lower order and?higher order organocuprates: Application of acetone O-(4-Chlorophenylsulfonyl)oxime in the construction of the C?N bond at room temperature
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Electrophilic amination reaction was performed with lower order and?higher order organocuprates using acetone O-(4-Chlorophenylsulfonyl)oxime (1). It was proceeded smoothly at room temperature in the presence of organocuprates to provide the corresponding primary amines in good yields with 10 and 60 min, respectively. The primary amine yields of the electrophilic amination of bromomagnesium organocyanocuprates and dibromomagnesium diorganocyanocuprates were obtained 52–72% and 58–83%, respectively. We observed that higher order organocuprates were more successful than lower order organocuprates in the synthesis of functionalized arylamines by electrophilic amination.
- Duran, Serdar,Korkmaz, Adem
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p. 2077 - 2087
(2021/05/27)
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- Ligand compound for copper catalyzed aryl halide coupling reaction, catalytic system and coupling reaction
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The invention provides a ligand compound capable of being used for copper catalyzed aryl halide coupling reaction, the ligand compound is a three-class compound containing a 2-(substituted or non-substituted) aminopyridine nitrogen-oxygen group, and the invention also provides a catalytic system for the aryl halide coupling reaction. Thecatalytic system comprises a copper catalyst, a compound containing a 2-(substituted or non-substituted) aminopyridine nitrogen-oxygen group adopted as a ligand, alkali and a solvent, and meanwhile, the invention also provides a system for the aryl halide coupling reaction adopting the catalyst system. The compound containing the 2-(substituted or non-substituted) aminopyridine nitrogen oxygen group can be used as the ligand for the copper catalyzed aryl chloride coupling reaction, and the ligand is stable under a strong alkaline condition and can well maintain catalytic activity when being used for the copper-catalyzed aryl chloride coupling reaction. In addition, the copper catalyst adopting the compound as the ligand can particularly effectively promote coupling of copper catalyzed aryl chloride and various nucleophilic reagents which are difficult to generate under conventional conditions, C-N, C-O and C-S bonds are generated, and numerous useful small molecule compounds are synthesized. Therefore, the aryl halide coupling reaction has a very good large-scale application prospect by adopting the copper catalysis system of the ligand.
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Paragraph 0111-0119
(2021/05/29)
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- Iridium-Triggered Allylcarbamate Uncaging in Living Cells
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Designing a metal catalyst that addresses the major issues of solubility, stability, toxicity, cell uptake, and reactivity within complex biological milieu for bioorthogonal controlled transformation reactions is a highly formidable challenge. Herein, we report an organoiridium complex that is nontoxic and capable of the uncaging of allyloxycarbonyl-protected amines under biologically relevant conditions and within living cells. The potential applications of this uncaging chemistry have been demonstrated by the generation of diagnostic and therapeutic agents upon the activation of profluorophore and prodrug in a controlled fashion within HeLa cells, providing a valuable tool for numerous potential biological and therapeutic applications.
- Gupta, Ajay,Gupta, Shalini,Mahawar, Pritam,Prasad, Puja,Sasmal, Pijus K.,Singh, Neelu
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supporting information
p. 12644 - 12650
(2021/09/06)
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- Porous polymeric ligand promoted copper-catalyzed C-N coupling of (hetero)aryl chlorides under visible-light irradiation
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A porous polymeric ligand (PPL) has been synthesized and complexed with copper to generate a heterogeneous catalyst (Cu@PPL) that has facilitated the efficient C-N coupling with various (hetero)aryl chlorides under mild conditions of visible-light irradiation at 80 °C (58 examples, up to 99% yields). This method could be applied to both aqueous ammonia and substituted amines, and is compatible to a variety of functional groups and heterocycles, as well as allows tandem C-N couplings with conjunctive dihalides. Furthermore, the heterogeneous characteristic of Cu@PPL has enabled a straightforward catalyst separation in multiple times of recycling with negligible catalytic efficiency loss by simple filtration, affording reaction mixtures containing less than 1 ppm of Cu residue. [Figure not available: see fulltext.]
- Wang, Erfei,Chen, Kaixuan,Chen, Yinan,Zhang, Jiawei,Lin, Xinrong,Chen, Mao
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- Crystallography-guided discovery of carbazole-based retinoic acid-related orphan receptor gamma-t (RORγt) modulators: insights into different protein behaviors with “short” and “long” inverse agonists
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A series of 6-substituted carbazole-based retinoic acid-related orphan receptor gamma-t (RORγt) modulators were discovered through 6-position modification guided by insights from the crystallographic profiles of the “short” inverse agonist 6. With the increase in the size of the 6-position substituents, the “short” inverse agonist 6 first reversed its function to agonists and then to “long” inverse agonists. The cocrystal structures of RORγt complexed with the representative “short” inverse agonist 6 (PDB: 6LOB), the agonist 7d (PDB: 6LOA) and the “long” inverse agonist 7h (PDB: 6LO9) were revealed by X-ray analysis. However, minor differences were found in the binding modes of “short” inverse agonist 6 and “long” inverse agonist 7h. To further reveal the molecular mechanisms of different RORγt inverse agonists, we performed molecular dynamics simulations and found that “short” or “long” inverse agonists led to different behaviors of helixes H11, H11’, and H12 of RORγt. The “short” inverse agonist 6 destabilizes H11’ and dislocates H12, while the “long” inverse agonist 7h separates H11 and unwinds H12. The results indicate that the two types of inverse agonists may behave differently in downstream signaling, which may help identify novel inverse agonists with different regulatory mechanisms.
- Yu, Ming-cheng,Yang, Feng,Ding, Xiao-yu,Sun, Nan-nan,Jiang, Zheng-yuan,Huang, Ya-fei,Yan, Yu-rong,Zhu, Chen,Xie, Qiong,Chen, Zhi-feng,Guo, Si-qi,Jiang, Hua-liang,Chen, Kai-xian,Luo, Cheng,Luo, Xiao-min,Chen, Shi-jie,Wang, Yong-hui
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p. 1524 - 1534
(2020/12/01)
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- A Metal-Free Direct Arene C?H Amination
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The synthesis of aryl amines via the formation of a C?N bond is an essential tool for the preparation of functional materials, active pharmaceutical ingredients and bioactive products. Usually, this chemical connection is only possible by transition metal-catalyzed reactions, photochemistry or electrochemistry. Here, we report a metal-free arene C?H amination using hydroxylamine derivatives under benign conditions. A charge transfer interaction between the aminating reagents TsONHR and the arene substrates enables the chemoselective amination of the arene, even in the presence of various functional groups. Oxygen was crucial for an effective conversion and its accelerating role for the electron transfer step was proven experimentally. In addition, this was rationalized by a theoretical study which indicated the involvement of a dioxygen-bridged complex with a “Sandwich-like” arrangement of the aromatic starting materials and the aminating agents at the dioxygen molecule. (Figure presented.).
- Wang, Tao,Hoffmann, Marvin,Dreuw, Andreas,Hasagi?, Edina,Hu, Chao,Stein, Philipp M.,Witzel, Sina,Shi, Hongwei,Yang, Yangyang,Rudolph, Matthias,Stuck, Fabian,Rominger, Frank,Kerscher, Marion,Comba, Peter,Hashmi, A. Stephen K.
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supporting information
p. 2783 - 2795
(2021/04/05)
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- The graphite-catalyzed: ipso -functionalization of arylboronic acids in an aqueous medium: metal-free access to phenols, anilines, nitroarenes, and haloarenes
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An efficient, metal-free, and sustainable strategy has been described for the ipso-functionalization of phenylboronic acids using air as an oxidant in an aqueous medium. A range of carbon materials has been tested as carbocatalysts. To our surprise, graphite was found to be the best catalyst in terms of the turnover frequency. A broad range of valuable substituted aromatic compounds, i.e., phenols, anilines, nitroarenes, and haloarenes, has been prepared via the functionalization of the C-B bond into C-N, C-O, and many other C-X bonds. The vital role of the aromatic π-conjugation system of graphite in this protocol has been established and was observed via numerous analytic techniques. The heterogeneous nature of graphite facilitates the high recyclability of the carbocatalyst. This effective and easy system provides a multipurpose approach for the production of valuable substituted aromatic compounds without using any metals, ligands, bases, or harsh oxidants.
- Badgoti, Ranveer Singh,Dandia, Anshu,Parewa, Vijay,Rathore, Kuldeep S.,Saini, Pratibha,Sharma, Ruchi
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p. 18040 - 18049
(2021/05/29)
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- The benzyl can be selectively removed by visible light or near visible light. Method for protecting allyl and propargyl group
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The invention provides a method for selectively removing benzyl, allyl and propargyl protecting groups by visible light or near visible light, namely a substrate containing benzyl, allyl or propargyl protecting groups. The method has the advantages of simple operation, safe and clean visible light or near visible light as excitation conditions, cheap and easily available reagents, high reaction yield, high reaction chemistry and regional selectivity, and is suitable for selective removal of benzyl, allyl and propargyl protecting groups in various substrates.
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Paragraph 0016
(2021/10/16)
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- Reductive Formylation of Nitroarenes using HCOOH over Bimetallic C?N Framework Derived from the Integration of MOF and COF
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CoZn embedded C?N framework is prepared by the carbonization of CoZn containing MOF integrated with COF porous architecture in Ar atmosphere. The graphitic nature of porous carbon is confirmed from Raman analysis. The porosity and nanostructure information are retrieved from N2-sorption and transmission electron microscopic analysis, respectively. The incorporation of different metals and their oxidation states and types of nitrogen present in the C?N framework are confirmed from X-ray photoelectron spectroscopy. The basicity of the materials is determined from a CO2-temperature programmed desorption. ZnCo embedded C?N framework exhibits excellent activity in the selective reductive formylation using HCOOH. For comparison, more than 15 materials are prepared, and their activities are compared. Several control experiments are performed to establish a structure-activity relation. The recycling experiment, hot-filtration test, and poisoning experiment demonstrate the metal embedded porous C?N framework‘s recyclability and stability. A reaction mechanism for the reductive N-formylation of nitroaromatics is presented based on structure-activity relationship, control reactions, and physicochemical characterizations. The development of interesting MOF-COF-derived metal nanoclusters embedded C?N framework for selective reductive formylation of nitroaromatics using formic acid will be highly attractive to catalysis researchers and industrialists.
- Kumar Kar, Ashish,Srivastava, Rajendra
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p. 3174 - 3183
(2021/05/27)
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- Catalytic Hydrogenation of Urea Derivatives and Polyureas
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We present herein the catalytic hydrogenation of various urea derivatives to amines and methanol. The reaction is catalyzed by a ruthenium or an iridium Macho pincer complex and produces amine and methanol in very good to excellent yields. Moreover, we also expand this concept to demonstrate the first example of the hydrogenative depolymerization of polyureas to produce diamines and methanol in moderate yields.
- Kumar, Amit,Luk, James
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supporting information
p. 4546 - 4550
(2021/08/30)
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- Indirect reduction of CO2and recycling of polymers by manganese-catalyzed transfer hydrogenation of amides, carbamates, urea derivatives, and polyurethanes
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The reduction of polar bonds, in particular carbonyl groups, is of fundamental importance in organic chemistry and biology. Herein, we report a manganese pincer complex as a versatile catalyst for the transfer hydrogenation of amides, carbamates, urea derivatives, and even polyurethanes leading to the corresponding alcohols, amines, and methanol as products. Since these compound classes can be prepared using CO2as a C1 building block the reported reaction represents an approach to the indirect reduction of CO2. Notably, these are the first examples on the reduction of carbamates and urea derivatives as well as on the C-N bond cleavage in amides by transfer hydrogenation. The general applicability of this methodology is highlighted by the successful reduction of 12 urea derivatives, 26 carbamates and 11 amides. The corresponding amines, alcohols and methanol were obtained in good to excellent yields up to 97%. Furthermore, polyurethanes were successfully converted which represents a viable strategy towards a circular economy. Based on control experiments and the observed intermediates a feasible mechanism is proposed.
- Liu, Xin,Werner, Thomas
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p. 10590 - 10597
(2021/08/20)
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- Selective Carbon-Carbon Bond Amination with Redox-Active Aminating Reagents: A Direct Approach to Anilines?
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Amines are among the most fundamental motifs in chemical synthesis, and the introduction of amine building blocks via selective C—C bond cleavage allows the construction of nitrogen compounds from simple hydrocarbons through direct skeleton modification. Herein, we report a novel method for the preparation of anilines from alkylarenes via Schmidt-type rearrangement using redox-active amination reagents, which are easily prepared from hydroxylamine. Primary amines and secondary amines were prepared from corresponding alkylarenes or benzyl alcohols under mild conditions. Good compatibility and valuable applications of the transformation were also displayed.
- Qiu, Xu,Wang, Yachong,Su, Lingyu,Jin, Rui,Song, Song,Qin, Qixue,Li, Junhua,Zong, Baoning,Jiao, Ning
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supporting information
p. 3011 - 3016
(2021/09/13)
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- Iron-Catalyzed Hydrogen Transfer Reduction of Nitroarenes with Alcohols: Synthesis of Imines and Aza Heterocycles
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A straightforward and selective reduction of nitroarenes with various alcohols was efficiently developed using an iron catalyst via a hydrogen transfer methodology. This protocol led specifically to imines in 30-91% yields, with a good functional group tolerance. Noticeably, starting from o-nitroaniline derivatives, in the presence of alcohols, benzimidazoles can be obtained in 64-72% yields when the reaction was performed with an additional oxidant, DDQ, and quinoxalines were prepared from 1,2-diols in 28-96% yields. This methodology, unprecedented at iron for imines, also provides a sustainable alternative for the preparation of quinoxalines and benzimidazoles.
- Wu, Jiajun,Darcel, Christophe
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supporting information
p. 1023 - 1036
(2021/01/09)
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- Selective Reduction of Nitroarenes to Arylamines by the Cooperative Action of Methylhydrazine and a Tris(N-heterocyclic thioamidate) Cobalt(III) Complex
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We report an efficient catalytic protocol that chemoselectively reduces nitroarenes to arylamines, by using methylhydrazine as a reducing agent in combination with the easily synthesized and robust catalyst tris(N-heterocyclic thioamidate) Co(III) complex [Co(κS,N-tfmp2S)3], tfmp2S = 4-(trifluoromethyl)-pyrimidine-2-thiolate. A series of arylamines and heterocyclic amines were formed in excellent yields and chemoselectivity. High conversion yields of nitroarenes into the corresponding amines were observed by using polar protic solvents, such as MeOH and iPrOH. Among several hydrogen donors that were examined, methylhydrazine demonstrated the best performance. Preliminary mechanistic investigations, supported by UV-vis and NMR spectroscopy, cyclic voltammetry, and high-resolution mass spectrometry, suggest a cooperative action of methylhydrazine and [Co(κS,N-tfmp2S)3] via a coordination activation pathway that leads to the formation of a reduced cobalt species, responsible for the catalytic transformation. In general, the corresponding N-arylhydroxylamines were identified as the sole intermediates. Nevertheless, the corresponding nitrosoarenes can also be formed as intermediates, which, however, are rapidly transformed into the desired arylamines in the presence of methylhydrazine through a noncatalytic path. On the basis of the observed high chemoselectivity and yields, and the fast and clean reaction processes, the present catalytic system [Co(κS,N-tfmp2S)3]/MeNHNH2 shows promise for the efficient synthesis of aromatic amines that could find various industrial applications.
- Ioannou, Dimitris I.,Gioftsidou, Dimitra K.,Tsina, Vasiliki E.,Kallitsakis, Michael G.,Hatzidimitriou, Antonios G.,Terzidis, Michael A.,Angaridis, Panagiotis A.,Lykakis, Ioannis N.
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supporting information
p. 2895 - 2906
(2021/02/27)
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- Method for synthesizing heteroatom- substituted aromatic compound from styrene compound
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The invention discloses a method for synthesizing a heteroatom-substituted aromatic compound from a styrene compound, which comprises the following steps of: mixing a styrene compound with a general formula (I) and a heteroatom-containing compound with a general formula (II), and reacting in the presence of an acid additive and an organic solvent to obtain a heteroatom-substituted compound with ageneral formula (III). According to the synthesis method disclosed by the invention, a large amount of styrene compounds are used as raw materials and react to generate aromatic amine or phenol compounds under the action of no metal catalysis; and compared with the traditional aromatic amine and phenol synthesis method, the method has the advantages of high yield, simple conditions, low waste discharge amount, no metal participation, simple reaction equipment, easiness in industrial production and the like.
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Paragraph 0156-0160
(2021/02/06)
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- Minimization of Back-Electron Transfer Enables the Elusive sp3 C?H Functionalization of Secondary Anilines
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Anilines are some of the most used class of substrates for application in photoinduced electron transfer. N,N-Dialkyl-derivatives enable radical generation α to the N-atom by oxidation followed by deprotonation. This approach is however elusive to monosubstituted anilines owing to fast back-electron transfer (BET). Here we demonstrate that BET can be minimised by using photoredox catalysis in the presence of an exogenous alkylamine. This approach synergistically aids aniline SET oxidation and then accelerates the following deprotonation. In this way, the generation of α-anilinoalkyl radicals is now possible and these species can be used in a general sense to achieve divergent sp3 C?H functionalization.
- Zhao, Huaibo,Leonori, Daniele
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supporting information
p. 7669 - 7674
(2021/03/08)
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- Methoxy aniline compound and synthesis method thereof
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The invention mainly relates to a preparation method of anisidine. According to the technical scheme, under the promotion of the photocatalyst and blue light, in the argon atmosphere, nitro compounds and methanol generate methoxyaniline, wherein products and additional products with stable molecular structures and excellent chemical properties are prepared, wherein a photocatalyst and a blue light source are used in the method, and a new path is provided for synthesis of methoxyaniline compounds. The method has the characteristics of mild reaction conditions, simple reaction system, less reaction equipment, simplicity and convenience in experimental operation and the like. The methoxyaniline derivative and the synthetic method thereof can be applied to a plurality of industrial production fields of dyes, pesticides, medicines, rubber additives and the like. The method is particularly suitable for scientific research, development and utilization of efficient and selective synthesis of methoxyaniline compounds by a one-pot method.
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Paragraph 0027; 0030-0032; 0041-0042
(2021/05/19)
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- A convenient Hofmann reaction of carboxamides and cyclic imides mediated by trihaloisocyanuric acids
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A simple, efficient and pot-economic approach in a single vessel has been developed for conversion of aromatic and aliphatic carboxamides into primary amines with one fewer carbom atom (Hofmann reaction) in 38–89 % yield by reacting with trichloro- or tribromoisocyanuric acid and sodium hydroxide in aqueous acetonitrile. Under the same reaction conditions, cyclic imides gave amino acids (69–83 %). The role of the trihaloisocyanuric acids is the in situ generation of N-haloamides, key-intermediates for the Hofmann reaction. The scalability of the methodology was demonstrated by a multigram-scale transformation of phthalimide into anthranilic acid in 77 % yield.
- Bastos, Gustavo A.,de Mattos, Marcio C.S.
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- Unlocking Amides through Selective C–N Bond Cleavage: Allyl Bromide-Mediated Divergent Synthesis of Nitrogen-Containing Functional Groups
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We report a new set of reactions based on the unlocking of amides through simple treatment with allyl bromide, creating a common platform for accessing a diverse range of nitrogen-containing functional groups such as primary amides, sulfonamides, primary amines, N-acyl compounds (esters, thioesters, amides), and N-sulfonyl esters. The method has potential industrial applicability, as demonstrated through gram-scale syntheses in batch and in a continuous flow system.
- Govindan, Karthick,Chen, Nian-Qi,Chuang, Yu-Wei,Lin, Wei-Yu
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p. 9419 - 9424
(2021/11/30)
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- Anhydrous Hydrogen Iodide-Mediated Reductive Indolization of in Situ-Generated Cyclopropyl Hydrazones
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Fischer-type indolization of N-aryl-C-cyclopropyl hydrazones generated in situ followed by chemoselective reduction using tert-butyl iodide as an anhydrous HI generator was developed. This protocol provides indoles bearing carboxylic acid derivative units. A series of control experiments indicated the HI-mediated formation and reduction of spirocyclopropyl indolenines. Anhydrous HI functions as a Br?nsted acid as well as a reducing agent, facilitating the successful conversion of unstable reaction intermediates and iodinated mixtures in equilibrium.
- Fujioka, Hiroki,Takeda, Norihiko,Ueda, Masafumi,Yasui, Motohiro
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supporting information
(2021/12/17)
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- A polyamine dendritic polymer-copper complex: A reusable catalyst for the additive-free amination of aryl bromides, and iodides
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A porphyrin-initiated amine-functionalized polyepichlorohydrin dendritic polymer (PPECH-Amine) was effectively synthesized, and its water-soluble copper complex (PPECH-Amine-Cu) was developed by treating it with copper acetate. PPECH-Amine and PPECH-Amine-Cu were characterised by different spectroscopic and microscopic techniques. PPECH-Amine-Cu was identified as a reusable catalyst for the amination of bromo- and iodo-benzene derivatives in aqueous media. Due to the presence of residual amino groups in the PPECH-Amine-Cu catalyst, the protocol does not need any additional base additive, as ammonia itself acts as a base and a coupling partner. Due to the good water-soluble nature of this catalyst, it can be easily separated and reused up to six reaction cycles without any loss in its activity.
- Avudaiappan,Palmurukan,Unnikrishnan,Sreekumar
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p. 1477 - 1484
(2020/02/05)
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- Copper and L-(?)-quebrachitol catalyzed hydroxylation and amination of aryl halides under air
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L-(?)-Quebrachitol, a natural product obtained from waste water of the rubber industry, was utilized as an efficient ligand for the copper-catalyzed hydroxylation and amination of aryl halides to selectively give phenols and aryl amines in water or 95percent ethanol. In addition, the hydroxylation of 2-chloro-4-hydroxybenzoic acid was validated on a 100-g scale under air.
- Bao, Xuefei,Chen, Guoliang,Dong, Jinhua,Du, Fangyu,Li, Hui,Liang, Xinjie,Wu, Ying,Zhang, Yongsheng
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supporting information
(2020/08/03)
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- A new ligand for copper-catalyzed amination of aryl halides to primary(hetero)aryl amines
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N,N′-Bis(3,5-dimethoxyphenyl)cyclopentane-1,1-dicarboxamide was found as a new ligand for copper-catalyzed amination of aryl iodides, bromides and chlorides to afford various primary (hetero)aryl amines. These reactions proceeded efficiently under mild conditions when inexpensive aqueous ammonia (28% NH3 in H2O) was used as the amino source.
- Chen, Dong,Dong, Xinrui,Jiang, Shang,Jiang, Sheng,Qiu, Yatao,Wu, Xiaoxing
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supporting information
(2020/02/11)
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- Atomically Dispersed Co Catalyst for Efficient Hydrodeoxygenation of Lignin-Derived Species and Hydrogenation of Nitroaromatics
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Single-atom catalysts (SACs) have attracted much attention due to their outstanding catalytic performance in heterogeneous catalysis. Here, we report a template sacrificial method to fabricate an atomically dispersed Co catalyst; three kinds of silica templates with different microstructures (MCM-41, SBA-15, and FDU-12) were employed and the effect of pore structure of the templates on the dispersity of Co was investigated. The catalysts fabricated with different templates presented different Co dispersities, leading to distinguishing catalytic performance. The optimized Co1?NC-(SBA) catalyst with atomically dispersed Co displayed outstanding catalytic activity for the hydrodeoxygenation (HDO) of lignin-derived species as well as the hydrogenation of various nitroaromatics. The reaction mechanism of the HDO of vanillin was investigated by using density functional theory calculations as well.
- Du, Congcong,Gao, Shutao,Gao, Yongjun,Huang, Jianyu,Meng, Tao,Qiao, Yuqing,Shang, Ningzhao,Shen, Tongde,Wang, Chun,Wang, Haijun,Wang, Junmin,Wang, Zhi,Wu, Qiuhua,Zhang, Longkang
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p. 8672 - 8682
(2020/09/18)
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- Method for reducing aromatic nitro compounds into aromatic amine compounds
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The invention discloses a method for reducing aromatic nitro compounds into aromatic amine compounds. The aromatic nitro compounds are reacted at a temperature of 110-130 DEG C in an inert or air atmosphere under the action of a rhodium catalyst by using water as a solvent, isopropanol as a hydrogen source and potassium phosphate or sodium carbonate as an alkali to obtain the aromatic amine compounds. The method has the advantages of simplicity in operation, greenness, environmental friendliness, reduction of environmental pollution, high reaction yield, amplified gram-scale preparation of theamine compounds, high catalyst activity, recyclability and low industrial production cost.
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Paragraph 0018-0019
(2020/03/25)
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- A Pd confined hierarchically conjugated covalent organic polymer for hydrogenation of nitroaromatics: Catalysis, kinetics, thermodynamics and mechanism
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Herein, we propose a fast and scalable synthesis of a triazine based hierarchically conjugated covalent organic polymer under solvent and additive free conditions through a single step process. The synthesized material CCTP (Cyanuric Chloride-Thiourea-Polymer) was thoroughly characterized by various physicochemical techniques. The CCTP exhibited regular sponginess and excellent chemical as well as thermal stability. The solvent and additive free approach for CCTP synthesis provides a sustainable alternative for classical solvothermal methods. The CCTP was immobilized with Pd (0) and subsequently a heterogeneous material Pd&at;CCTP was obtained, which was used as an efficient catalyst for the hydrogenation of nitroarenes. The rate constant and Ea were measured to be 2.08 × 10-2 s-1 and 15.67 kJ mol-1 respectively and thereafter other thermodynamic parameters like ΔH, ΔS and ΔG for the hydrogenation of p-nitrophenol were also calculated. The obtained results indicate that the catalytic hydrogenation of p-nitrophenol is a non-spontaneous and endothermic process. We have also investigated the effect of surfactants (NH4OH, FA, and N2) on the reaction performance, and consequently NH4OH and FA both slow down the reaction while N2 doesn't affect the reaction medium. Further, we calculated the rate constant for the hydrogenation of 2,4-dinitrophenol and 2,4,6-trinitrophenol. An array of nitroarenes were further reduced to extend the substrate scope at RT; high TOFs were observed. Besides, Pd&at;CCTP showed excellent reusability in hydrogenation reactions without evident performance falloff.
- Awasthi, Satish Kumar,Yadav, Deepika
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p. 4295 - 4303
(2020/07/30)
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- Immobilization of Au nanoparticles on poly(glycidyl methacrylate)-functionalized magnetic nanoparticles for enhanced catalytic application in the reduction of nitroarenes and Suzuki reaction
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We report a novel strategy for the synthesis of magnetic nanocomposite for highly efficient catalysis. Poly(glycidyl methacrylate) (PGMA) chains were grafted to the surface of magnetic nanoparticles (MNPs) through surface-initiated reversible addition-fragmentation chain transfer polymerization. Then, the oxirane rings in the PGMA chains were opened with 2,6-diamino pyridine (DAP) molecules as ligands to prepare the solid support. Finally, this magnetic nanocomposite was used for the immobilization of gold nanoparticles. Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, transmission electron microscopy, scanning electron microscopy, gel permeation chromatography, vibrating sample magnetometry, and atomic absorption spectroscopy were used for characterization of the catalyst. The loading of gold nanoparticles on the solid support was 0.52 mmol/g. The catalytic activity of the prepared catalyst (MNP@PGMA@DAP@Au) was evaluated for the reduction of nitro compounds and C–C coupling reaction in water. The catalyst can be easily recovered and reused seven times without significant loss of catalytic activity.
- Pourjavadi, Ali,Kohestanian, Mohammad,Keshavarzi, Nahid
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- Tandem selective reduction of nitroarenes catalyzed by palladium nanoclusters
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We report a catalytic tandem reduction of nitroarenes by sodium borohydride (NaBH4) in aqueous solution under ambient conditions, which can selectively produce five categories of nitrogen-containing compounds: anilines, N-aryl hydroxylamines, azoxy-, azo- and hydrazo-compounds. The catalyst is in situ-generated ultrasmall palladium nanoclusters (Pd NCs, diameter of 1.3 ± 0.3 nm) from the reduction of Pd(OAc)2 by NaBH4. These highly active Pd NCs are stabilized by surface-coordinated nitroarenes, which inhibit the further growth and aggregation of Pd NCs. By controlling the concentration of Pd(OAc)2 (0.1-0.5 mol% of nitroarene) and NaBH4, the water/ethanol solvent ratio and the tandem reaction sequence, each of the five categories of N-containing compounds can be obtained with excellent yields (up to 98%) in less than 30 min at room temperature. This tunable catalytic tandem reaction works efficiently with a broad range of nitroarene substrates and offers a green and sustainable method for the rapid and large-scale production of valuable N-containing chemicals.
- Yan, Ziqiang,Xie, Xiaoyu,Song, Qun,Ma, Fulei,Sui, Xinyu,Huo, Ziyu,Ma, Mingming
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supporting information
p. 1301 - 1307
(2020/03/11)
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- Synthesis and characterization of a novel TEMPO?FeNi3/DFNS-laccase magnetic nanocomposite for the reduction of nitro compounds
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Water is an essential substance for life on earth and for all living things. Plants and animals need almost pure water to live; if it is contaminated with harmful chemicals and micro organisms, it will be impossible for them to survive. This study has tried to investigate the performance of catalyst to reduce nitro-aromatic combinations in the attendance of NaBH4 solution duo to the hydrogen source. TEMPO?FeNi3/DFNS-laccase MNPs was prepared, and its features were reviewed using SEM, TEM, XRD, TGA, VSM, AFM, and FTIR. Then, its strength as a nanocatalyst for removal of nitro-aromatic combinations was tested in contact time, initial concentration, the effects of pH and nanocatalyst amount was study. The results of this research proved that TEMPO?FeNi3/DFNS-laccase MNPs has a good return in removal of nitro-aromatic combinations, as its easy synthesis and reliable recovery.
- Mehrzad, Jamshid,Motavalizadehkakhky, Alireza,Saberi, Shima,Zhiani, Rahele
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p. 27297 - 27304
(2020/09/01)
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- Cycloglutaramide-based ligand, synthetic method of ligand, application of ligand in coupling reaction for synthesizing arylamine derivative and catalytic system
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The invention discloses a cycloglutaramide-based ligand having a general formula I shown in the specification, a synthetic method of the ligand, an application of the ligand in a coupling reaction forsynthesizing an arylamine derivative, and a catalytic system. The compounds represented by the formula I can be used as a ligand in the coupling reaction of synthesizing the arylamine derivative by using an aryl halide under catalysis of copper, especially the coupling reaction of aryl halide and an amine source to form a C-N bond under catalysis. Under mild reaction conditions, the high-yield arylamine derivative is obtained, and the ligand has a simple structure, convenient preparation and a less use amount.
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Paragraph 0106; 0107; 0108; 0109; 0110; 01111
(2020/03/12)
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- Heterogeneous photocatalysis of azides: Extending nitrene photochemistry to longer wavelengths
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The photodecomposition of azides to generate nitrenes usually requires wavelengths in the 300 nm region. In this study, we show that this reaction can be readily performed in the UVA region (368 nm) when catalyzed by Pd-decorated TiO2. In aqueous medium the reaction leads to amines, with water acting as the H source; however, in non-protic and non-nucleophilic media, such as acetonitrile, nitrenes recombine to yield azo compounds, while azirine-mediated trapping occurs in the presence of nucleophiles. The heterogeneous process facilitates catalyst separation while showing great chemoselectivity and high yields.
- Argüello, Juan E.,Lanterna, Anabel E.,Lemir, Ignacio D.,Scaiano, Juan C.
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supporting information
p. 10239 - 10242
(2020/10/02)
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- Copper catalyzed reduction of azides with diboron under mild conditions
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We report herein the first Cu catalyzed reduction of azides with B2pin2 (pin = pinacolato) as the reductant under very mild conditions. A series of primary amines and amides were obtained in moderate to excellent yields with high chemoselectivity and good functional group tolerance. This reaction can be performed with a cheap copper salt, a simple NHC ligand and a diboron reagent.
- Chen, Yang,Deng, Shengqi,Gao, Yihua,Liu, Liwen,Liu, Yu,Lu, Da,Wang, Qianwen,Zhang, Xiao
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supporting information
(2020/02/27)
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- C-H Amination of Arenes with Hydroxylamine
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This Letter describes the development of a TiIII-mediated reaction for the C-H amination of arenes with hydroxylamine. This reaction is applied to a variety of electron-rich (hetero)arene substrates, including a series of natural products and pharmaceuticals. It offers the advantages of mild conditions (room temperature), fast reaction rates (30 min), compatibility with ambient moisture and air, scalability, and the use of inexpensive commercial reagents.
- See, Yi Yang,Sanford, Melanie S.
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supporting information
p. 2931 - 2934
(2020/04/09)
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- Selective Photoinduced Reduction of Nitroarenes to N-Arylhydroxylamines
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We report the selective photoinduced reduction of nitroarenes to N-arylhydroxylamines. The present methodology facilitates this transformation in the absence of catalyst or additives and uses only light and methylhydrazine. This noncatalytic photoinduced transformation proceeds with a broad scope, excellent functional-group tolerance, and high yields. The potential of this protocol reflects on the selective and straightforward conversion of two general antibiotics, azomycin and chloramphenicol, to the bioactive hydroxylamine species.
- Kallitsakis, Michael G.,Ioannou, Dimitris I.,Terzidis, Michael A.,Kostakis, George E.,Lykakis, Ioannis N.
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supporting information
p. 4339 - 4343
(2020/06/08)
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- P-nitroanisole synthesis method
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The invention relates to a synthetic method of p-nitroanisole, which can effectively reduce the generation of by-products, avoid the refining process of the by-product p-nitrophenol and greatly improve the yield of p-nitroanisole; besides, a small amount of p-nitrophenol can be further reused in the synthetic steps of the invention in the subsequent wastewater treatment process. In addition, the p-nitroanisole obtained by the method disclosed by the invention has higher product quality.
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- Sulfuryl Fluoride Mediated Synthesis of Amides and Amidines from Ketoximes via Beckmann Rearrangement
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A metal-free and redox-neutral method for Beckmann rearrangement employing inexpensive and readily available SO2F2 gas is described. The reported transformation proceeds at ambient temperature and is compatible with a wide range of sterically and electronically diverse aromatic, heteroaromatic, aliphatic and lignin-like oximes providing amides in good to excellent yields. The reaction proceeds through the formation of an imidoyl fluoride intermediate that can also be used for the synthesis of amidines.
- Gurjar, Jitendra,Fokin, Valery V.
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p. 10402 - 10405
(2020/07/25)
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- Selective Room-Temperature Hydrogenation of Amides to Amines and Alcohols Catalyzed by a Ruthenium Pincer Complex and Mechanistic Insight
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We report a room-temperature protocol for the hydrogenation of various amides to produce amines and alcohols. Compared with most previous reports for this transformation, which use high temperatures (typically, 100-200 °C) and H2 pressures (10-100 bar), this system proceeds under extremely mild conditions (RT, 5-10 bar of H2). The hydrogenation is catalyzed by well-defined ruthenium-PNNH pincer complexes (0.5 mol %) with potential dual modes of metal-ligand cooperation. An unusual Ru-amidate complex was formed and crystallographically characterized. Mechanistic investigations indicate that the room-temperature hydrogenation proceeds predominantly via the Ru-N amido/amine metal-ligand cooperation.
- Ben-David, Yehoshoa,Kar, Sayan,Kumar, Amit,Leitus, Gregory,Milstein, David,Rauch, Michael
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p. 5511 - 5515
(2020/07/21)
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- Electronic Structures and Reactivity Profiles of Aryl Nitrenoid-Bridged Dicopper Complexes
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Dicopper complexes templated by dinucleating, pacman dipyrrin ligand scaffolds (Mesdmx, tBudmx: Dimethylxanthine-bridged, cofacial bis-dipyrrin) were synthesized by deprotonation/metalation with mesitylcopper (CuMes; Mes: Mesityl) or by transmetalation with cuprous precursors from the corresponding deprotonated ligand. Neutral imide complexes (Rdmx)Cu2(μ2-NAr) (R: Mes, tBu; Ar: 4-MeOC6H4, 3,5-(F3C)2C6H3) were synthesized by treatment of the corresponding dicuprous complexes with aryl azides. While one-electron reduction of (Mesdmx)Cu2(μ2-N(C6H4OMe)) with potassium graphite initiates an intramolecular, benzylic C-H amination at room temperature, chemical reduction of (tBudmx)Cu2(μ2-NAr) leads to isolable [(tBudmx)Cu2(μ2-NAr)]-product salts. The electronic structures of the thermally robust [(tBudmx)Cu2(μ2-NAr)]0/-complexes were assessed by variable-temperature electron paramagnetic resonance spectroscopy, X-ray absorption spectroscopy (Cu L2,3/K-edge, N K-edge), optical spectroscopy, and DFT/CASSCF calculations. These data indicate that the formally Class IIIA mixed valence complexes of the type [(Rdmx)Cu2(μ2-NAr)]-feature significant NAr-localized spin following reduction from electronic population of the [Cu2(μ2-NAr)] ? manifold, contrasting previous methods for engendering iminyl character through chemical oxidation. The reactivity of the isolable imido and iminyl complexes are examined for prototypical radical-promoted reactivity (e.g., nitrene transfer and H-atom abstraction), where the divergent reactivity is rationalized by the relative degree of N-radical character afforded from different aryl substituents.
- Carsch, Kurtis M.,Lukens, James T.,Dimucci, Ida M.,Iovan, Diana A.,Zheng, Shao-Liang,Lancaster, Kyle M.,Betley, Theodore A.
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supporting information
p. 2264 - 2276
(2020/02/18)
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