- Ionic liquids as new media for electrophilic trifluoromethylation reactions
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The electrophilic trifluoromethylation of aniline with a range of trifluoromethyl sulfonium salts has been studied in ionic liquids as solvent. The best ionic liquid for this reaction was identified after extensive scrutiny of the influence of the cation's nature (imidazolium or pyridinium salts), the effect of the alkyl side chain length of the cation, as well as that of the counter anion. Recycling experiments have demonstrated that the purification protocol was greatly simplified over conventional reactions performed in DMF and that the solvent could be reused five times without significant loss of activity.
- Pégot, Bruce,Macé, Yohan,Urban, Céline,Diter, Patrick,Blazejewski, Jean-Claude,Magnier, Emmanuel
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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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- 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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- Highly efficient N-doped carbon supported FeSx-Fe2O3 catalyst for hydrogenation of nitroarenes via pyrolysis of sulfurized N,Fe-containing MOFs
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Integrating MOFs as precursor, especially for employing N-containing organic linkers, with sulfides is an effective method to prepare the highly efficient N-doped carbon supported metal-based catalysts for hydrogenation of nitroarenes. In this work, a N,Fe-containing metal organic frameworks (MOFs; termed as MIL88-HMTA) with spindle-like structure was prepared via self-assembly method, in which hexamethylenetetramine (HMTA) linker was introduced as N source. Subsequently, N-doped carbon supported FeSx-Fe2O3 catalyst (named FeSx-Fe2O3@CN) was fabricated upon the pyrolysis of sulfurized MIL88-HMTA. Catalytic experiments reveal that the FeSx-Fe2O3@CN delivered excellent performance for hydrogenation of nitroarenes in comparison with those of catalyst without sulfidation process (Fe2O3@CN) and conventional MIL88 derived catalyst (Fe2O3@C). The XRD, TEM, SEM/EDX, Raman, UV, and XPS analyses have revealed that the developed FeSx-Fe2O3@CN catalyst exhibited outstanding catalytic efficiency was ascribed to synergistic effect between FeSx and Fe2O3 species, abundant structural defects, more Fe-Nx species, and strengthened decomposition ability of hydrazine hydrate (N2H4?H2O). Furthermore, the effect of sulfidation ratio (the mass ratio between thioacetamide and MIL88-HMTA) towards preparation of the developed FeSx-Fe2O3@CN on the catalytic activity of hydrogenation reaction was also systematically performed. Notably, the optimized catalyst (denoted as FeSx-Fe2O3@CN-8) exhibited unexpected performance and recyclability for hydrogenation of nitroarenes under mild condition. The pyrolysis of sulfurized N-containing MOFs may present a facile approach for fabricating MOFs-derived N-doped carbon supported catalysts, which provides a potential application in heterogeneous catalytic reactions.
- Li, Xuewei,She, Wei,Wang, Jing,Li, Weizuo,Li, Guangming
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- Photocatalytic reduction of nitroaromatics into anilines using CeO2-TiO2 nanocomposite
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The reduction of nitro compounds into amines is an important approach for synthetic and pharmaceutical chemistry. The reduced compounds are used as synthetic intermediates in the synthesis of therapeutic molecules. In the present work, we have fabricated cerium dioxide decorated TiO2 nanoparticles using a sol-gel-hydrothermal method. The synthesized nanocomposite was effectively reduced various nitro-compounds, specifically aromatic nitro compounds, into amines in visible light. All the nitro compounds screened in the photoreduction reaction showed >90% conversion with >96% selectivity. Chromatographic techniques confirmed the products obtained. The nanocomposite photocatalyst has excellent stability under the experimental condition and exhibited up to five cycles with no loss of metal content. The nanomaterials were characterized using various spectroscopic techniques.
- Chen, Changdong,Lu, Caiyun,Sun, Chengxin,Wang, Fangfang,Yin, Zhengfeng
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- Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
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Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
- Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 1618 - 1629
(2021/01/25)
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- A highly efficient LaOCl supported Fe-Fe3C-based catalyst for hydrogenation of nitroarenes fabricated by coordination-assisted pyrolysis
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Bi-metal-organic framework (bi-MOF) derived carbon-based catalysts have exhibited considerable potential for hydrogenation reactions; however, designing suitable bi-MOFs to fabricate highly efficient catalysts is still a great challenge. Herein, an efficient LaOCl supported Fe-Fe3C-based carbon-nitrogen catalyst (Fe-Fe3C-LaOCl/CN-hmta) was first prepared by bi-MOF (La-salenFe@HMTA)-templated pyrolysis. La-salenFe@HMTAwas synthesizedviathe coordination-assisted method,e.g., it is prepared by the coordination of N from the rich free imine (-CHN-) groups located on the La-salen complex to the Fe3+ions from Fe@HMTA. Catalytic experiments reveal that Fe-Fe3C-LaOCl/CN-hmta as a hydrogenation catalyst exhibits excellent performance for hydrogenation of nitroarenes in comparison with catalysts derived from Fe-urea MOFs (Fe-Fe3C-LaOCl/CN-urea) and Fe(NO3)3·9H2O derived catalysts (Fe-Fe3C-LaOCl/CN). On the basis of the nature of Fe-Fe3C-LaOCl/CN-hmta and the reaction results, it is concluded that the unique catalytic efficiency of Fe-Fe3C-LaOCl/CN-hmta depends significantly on the synergistic effect of Fe and Fe3C, large specific surface area and abundant structural defects. This piece of research provides a new approach for preparing highly efficient and stable Fe-Fe3C-based catalysts for hydrogenation of nitroarenesviathe coordination-assisted pyrolysis (CAP) method.
- Li, Guangming,Li, Weizuo,Li, Xuewei,She, Wei,Wang, Jing
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p. 4627 - 4635
(2021/07/12)
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- Sustainable and recyclable palladium nanoparticles–catalyzed reduction of nitroaromatics in water/glycerol at room temperature
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Palladium nanoparticles with unique catalytic activity and high stability are synthesized. These nanoparticles exhibit excellent catalytic reduction activity for nitroaromatics in green solvents in the presence of H2 at ambient pressure and temperature. The prominent advantages of this nanotechnology include low consumption of catalyst, excellent chemoselectivity, high reusability of the catalyst, and environmentally green solvents.
- Chen, Jin,Dai, Bencai,Liu, Changchun,Shen, Zhihao,Zhao, Yongde,Zhou, Yang
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p. 540 - 544
(2020/07/14)
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- Efficient hydrogenation catalyst designing via preferential adsorption sites construction towards active copper
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Based on the experimental and DFT calculation results, here for the first time we built preferential adsorption sites for nitroarenes by modification of the supported Cu catalysts surface with 1,10-phenathroline (1,10-phen), by which the yield of aniline via reduction of nitroarene is enhanced three times. Moreover, a macromolecular layer was in-situ generated on supported Cu catalysts to form a stable macromolecule modified supported Cu catalyst, i.e., CuAlOx-M. By applying the CuAlOx-M, a wide variety of nitroarene substrates react smoothly to afford the desired products in up to > 99% yield with > 99% selectivity. The method tolerates a variety of functional groups, including halides, ketone, amide, and C = C bond moieties. The excellent catalytic performance of the CuAlOx-M can be attributed to that the 1,10-phen modification benefits the preferential adsorption of nitrobenzene and slightly weakens adsorption of aniline on the supported nano-Cu surface.
- Dai, Xingchao,He, Dongcheng,Li, Teng,Shi, Feng,Wang, Hongli,Wang, Tao,Wang, Xinzhi
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p. 397 - 406
(2021/07/21)
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- Cu-Catalyzed Cross-Coupling of Nitroarenes with Aryl Boronic Acids to Construct Diarylamines
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The development and study of a simple copper-catalyzed reaction of nitroarenes with aryl boronic acids to form diarylamines that uses phenyl silane as the stoichiometric terminal reductant is described. This cross-coupling reaction requires as little as 2 mol % of CuX and 4 mol % of diphosphine for success and tolerates a broad range of functional groups on either the nitroarene or the aryl boronic acid to afford the amine in good yield. Mechanistic investigations established that the cross-coupling reaction proceeds via a nitrosoarene intermediate and that copper is required to catalyze both the deoxygenation of the nitroarene to afford the nitrosoarene and C-NAr bond formation of the nitrosoarene with the aryl boronic acid.
- Guan, Xinyu,Zhu, Haoran,Driver, Tom G.
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p. 12417 - 12422
(2021/10/12)
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- Selective primary aniline synthesis through supported Pd-catalyzed acceptorless dehydrogenative aromatization by utilizing hydrazine
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By utilizing hydrazine (N2H4) as the nitrogen source in the presence of a hydroxyapatite-supported Pd nanoparticle catalyst (Pd/HAP), various primary anilines can be selectively synthesized from cyclohexanonesviaacceptorless dehydrogenative aromatization. The strong nucleophilicity of N2H4and the stability of the hydrazone intermediates can effectively suppress the formation of the undesired secondary aniline byproducts.
- Lin, Wei-Chen,Yamaguchi, Kazuya,Yatabe, Takafumi
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supporting information
p. 6530 - 6533
(2021/07/07)
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- A Unified and Practical Method for Carbon–Heteroatom Cross-Coupling using Nickel/Photo Dual Catalysis
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While carbon–heteroatom cross-coupling reactions have been extensively studied, many methods are specific and limited to a particular set of substrates or functional groups. Reported here is a general method that allows for C?O, C?N and C?S cross-coupling reactions under one general set of conditions. We propose that an energy transfer pathway, in which an iridium photosensitizer produces an excited nickel(II) complex, is responsible for the key reductive elimination step that couples aryl bromides, iodides, and chlorides to 1° and 2° alcohols, amines, thiols, carbamates, and sulfonamides, and is amenable to scale up via a flow apparatus.
- Escobar, Randolph A.,Johannes, Jeffrey W.
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supporting information
(2020/04/17)
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- Commercially Available CuO Catalyzed Hydrogenation of Nitroarenes Using Ammonia Borane as a Hydrogen Source
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Tandem ammonia borane dehydrogenation and nitroarenes hydrogenation has been reported as a novel strategy for the preparation of aromatic amines. However, the practical application of this strategy is subjected to the high-cost and tedious preparation of supported noble metal nanocatalysts. The commercially available CuO powder is herein demonstrated to be a robust catalyst for hydrogenation of nitroarenes using ammonia borane as a hydrogen source under mild conditions. Numerous amines (even sterically hindered, halogenated, and diamines) could be obtained through this method. This monometallic catalyst is characteristic of support-free, excellent chemoselectivity, low-cost, and high recyclability, which will favor its future utilization in preparative reduction chemistry. Mechanistic studies are also carried out to clarify that diazene and azoxybenzene are key intermediates of this heterogeneous reduction.
- Du, Jialei,Chen, Jie,Xia, Hehuan,Zhao, Yiwei,Wang, Fang,Liu, Hong,Zhou, Weijia,Wang, Bin
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p. 2426 - 2430
(2020/03/30)
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- Insights into the Mechanism of Thiol-Triggered COS/H2S Release from N-Dithiasuccinoyl Amines
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The hydrolysis of carbonyl sulfide (COS) to form H2S by carbonic anhydrase has been demonstrated to be a viable strategy to deliver H2S in a biological system. Herein, we describe N-dithiasuccinoyl amines as thiol-triggered COS/H2S donors. Notably, thiol species especially GSH and homocysteine can trigger the release of both COS and H2S directly from several specific analogues via an unexpected mechanism. Importantly, two representative analogues Dts-1 and Dts-5 show intracellular H2S release, and Dts-1 imparts potent anti-inflammatory effects in LPS-challenged microglia cells. In conclusion, N-dithiasuccinoyl amine could serve as promising COS/H2S donors for either H2S biological studies or H2S-based therapeutics development.
- Zhou, Shengchao,Mou, Yujie,Liu, Miao,Du, Qian,Ali, Basharat,Ramprasad, Jurupula,Qiao, Chunhua,Hu, Li-Fang,Ji, Xingyue
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p. 8352 - 8359
(2020/09/07)
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- Synthesis of azobenzenes with high reactivity towards reductive cleavage: Enhancing the repertoire of hypersensitive azobenzenes and examining their dissociation behavior
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Trifluoromethyl (CF3), cyano (CN), and nitro (NO2) groups were demonstrated to be effective acceptors in the molecular design of triple-donor/acceptor-based hypersensitive azobenzenes. The synthesis of these reactive scaffolds requires only two steps with overall yields ranging from 70 to 73percent. UV–Vis absorption spectroscopy indicated that in all cases, a few seconds of exposure to mild reducing conditions is sufficient for complete cleavage of the azo bond. Liquid chromatography coupled with mass spectrometry (LC-MS) established the formation of two aniline fragments in the case of the CF3 and CN-substituted azobenzenes. In the case of the NO2-substituted compound, however, partial reduction of the nitro group results in the formation of three different anilines.
- Eom, Taejun,Khan, Anzar
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supporting information
(2020/05/19)
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- o-aminotrifluorotoluene synthesis method
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The invention discloses an o-aminotrifluorotoluene synthesis method, wherein trifluorotoluene is used as a raw material, and a target compound is obtained through two-step reaction of nitration and reduction. Compared with the method in the prior art, the method of the invention has the following characteristics that trifluorotoluene is used as the raw material, so that the source is wide, and thepreparation is convenient; the nitration reaction is carried out at a normal pressure and a low temperature, so that the corrosion of the material to the pipeline and the equipment is small, and thenitration reaction is safe and reliable to the environment and operators; and the cheap nickel catalyst is used for replacing the common noble metal catalysts such as palladium, platinum and the like,so that the production cost is reduced, the methanol as the solvent is convenient to recover and can be recycled, and the emission of organic matters in the production process is reduced.
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Paragraph 0006; 0013-0021
(2020/01/25)
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- Transition metal-free direct C–H trifluoromethyltion of (hetero)arenes with Togni's reagent
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A new transition-metal-free direct C–H trifluoromethylation reaction of (hetero)arenes with Togni's reagent was developed. This transformation proceeded smoothly under mild conditions and exhibited good tolerance of many synthetically relevant functional groups. It provided an alternative approach for the synthesis of trifluoromethylated (hetero)arenes.
- Chen, Xiaoyu,Ding, Licheng,Li, Linlin,Li, Jingya,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
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supporting information
(2019/12/30)
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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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- Electrochemically Driven, Ni-Catalyzed Aryl Amination: Scope, Mechanism, and Applications
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C-N cross-coupling is one of the most valuable and widespread transformations in organic synthesis. Largely dominated by Pd- and Cu-based catalytic systems, it has proven to be a staple transformation for those in both academia and industry. The current study presents the development and mechanistic understanding of an electrochemically driven, Ni-catalyzed method for achieving this reaction of high strategic importance. Through a series of electrochemical, computational, kinetic, and empirical experiments, the key mechanistic features of this reaction have been unraveled, leading to a second generation set of conditions that is applicable to a broad range of aryl halides and amine nucleophiles including complex examples on oligopeptides, medicinally relevant heterocycles, natural products, and sugars. Full disclosure of the current limitations and procedures for both batch and flow scale-ups (100 g) are also described.
- Kawamata, Yu,Vantourout, Julien C.,Hickey, David P.,Bai, Peng,Chen, Longrui,Hou, Qinglong,Qiao, Wenhua,Barman, Koushik,Edwards, Martin A.,Garrido-Castro, Alberto F.,Degruyter, Justine N.,Nakamura, Hugh,Knouse, Kyle,Qin, Chuanguang,Clay, Khalyd J.,Bao, Denghui,Li, Chao,Starr, Jeremy T.,Garcia-Irizarry, Carmen,Sach, Neal,White, Henry S.,Neurock, Matthew,Minteer, Shelley D.,Baran, Phil S.
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supporting information
p. 6392 - 6402
(2019/04/17)
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- Hydrogenation of Functionalized Nitroarenes Catalyzed by Single-Phase Pyrite FeS2 Nanoparticles on N,S-Codoped Porous Carbon
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Catalytic hydrogenation of nitroarenes is an industrially very important and environmentally friendly process for the production of anilines; however, highly chemoselective reduction of nitroarenes decorated with one or more reducible groups in a nitroarene molecule remains a challenge. Herein, a novel hybrid non-noble iron-based nanocatalyst (named as FeS2/NSC) was developed, which was prepared from biomass as C and N source together with inexpensive Fe(NO3)3 as Fe source through high-temperature pyrolysis in a straightforward and cost-effective procedure. Comprehensive characterization revealed that single-phase pyrite FeS2 nanoparticles with precisely defined composition and uniform size were homogeneously dispersed on N,S-codoped porous carbon with large specific surface area, hierarchical porous channels, and high pore volume. The resultant catalyst FeS2/NSC demonstrated good catalytic activity for hydrogenation of functionalized nitroarenes with good tolerance of various functional groups in water as a sustainable and green solvent. Compared with bulk pyrite FeS2 and other non-noble metal-based heterogeneous catalysts reported in the literature, a remarkably enhanced activity was observed under mild reaction conditions. More importantly, FeS2/NSC displayed exclusive chemoselectivity for the reduction of nitro groups for nitroarenes bearing varying readily reducible groups.
- Duan, Yanan,Dong, Xiaosu,Song, Tao,Wang, Zhaozhan,Xiao, Jianliang,Yuan, Youzhu,Yang, Yong
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- Catalytic hydrogenation of carbonyl and nitro compounds using an [: N, O] -chelate half-sandwich ruthenium catalyst
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A series of N,O-chelate half-sandwich ruthenium complexes for both carbonyl and nitro compound hydrogenation have been synthesized based on β-ketoamino ligands. All complexes exhibited high activity for the catalytic hydrogenation of a series of ketones and nitroarenes with molecular H2 as the reducing reagent in aqueous medium. Consequently, the catalytic system showed the catalytic TON values of 950 for 1-phenylethanol in acetophenone hydrogenation and 1960 for 1-chloro-4-nitrobenzene in p-chloroaniline hydrogenation. Good catalytic activity was displayed for various kinds of substrates with either electron-donating or electron-withdrawing groups. The neutral ruthenium complexes 1-4 were fully characterized using NMR, IR, and elemental analysis. Molecular structures of complexes 2 and 4 were further confirmed using single-crystal X-ray diffraction analysis.
- Yao, Zi-Jian,Zhu, Jing-Wei,Lin, Nan,Qiao, Xin-Chao,Deng, Wei
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p. 7158 - 7166
(2019/06/13)
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- Method of preparing aromatic amine compound through reduced aromatic nitro compound
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The invention discloses a method of preparing an aromatic amine compound through a reduced aromatic nitro compound. The method includes: in a simple condition, taking an aromatic nitro compound as a raw material, borane tetrahydrofuran as a hydrogen transfer reagent and metal salt of iron and copper which are cheap in price as a catalyst, and catalyzing the aromatic nitro compound for hydrogen transfer reaction to obtain a reduced aromatic amine compound. The method has the advantages that reaction condition is simple, yield is high, raw material universal applicability is high, the catalyst and the hydrogen transfer reagent are cheap in price and easy to obtain, and the method can still present high reproducibility during expanded amount reaction, therefore, an effective solution is provided for commercial preparation of the aromatic amine compound.
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Paragraph 0035-0039
(2019/06/27)
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- Effect of linker and metal on photoreduction and cascade reactions of nitroaromatics by M-UiO-66 metal organic frameworks
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The use of metal organic frameworks (MOFs) as photocatalysts is a promising and growing area of research. Given the diverse architectures, linkers, and metals, it is important to understand their effects on catalysis. Herein we compare six MOFs of the UiO-66 family towards photocatalytic reduction of nitro-aromatics to anilines. These MOFs differ in metal identity (Hf, Zr) and linker, and hence this systematic study provides insights to developing next generation MOFs. We found that Hf-based MOFs are superior to the more commonly studied Zr-analogues. Moreover, the linker identity also impact the photocatalysis, with pyridine-based linkers out-performing aniline based linkers and those that lack an embedded basic site. The MOFs studied have unique selectivities for the photoreduction and also allow for the one-pot synthesis of imines from aromatic aldehydes and nitro-aromatics.
- Elkin,Saouma
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supporting information
(2019/08/30)
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- Ultrafine NiMoOx nanoparticles confined in mesoporous carbon for the reduction of nitroarenes: effect of the composition and accessibility of the active sites
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The design of ultrafine NiMoOx nanoparticles (NPs) confined in hierarchically porous carbon remains a great challenge due to its high calcination temperature. In addition, the composition of active sites of NiMoOx NPs for the hydrogenation reaction is still ambiguous. Herein, we report a general approach for the synthesis of ultrafine NiMoOx NPs confined in mesoporous carbon with different morphologies and compositions using the replication method with SBA-15 as a hard template. The pore structure of mesoporous carbon and the Ni/Mo composition valence-state were discovered to be the main factors in the reduction of nitroarenes. The NiMoOx/mesoporous carbon-platelet (NiMoOx/MC-PL) with short mesochannels (~350 nm) and high surface area (~995 m2 g?1) possessed excellent catalytic activity towards the reduction of 4-nitrophenol, whereas NiMoOx/mesoporous carbon-hexagonal-prism (NiMoOx/MC-HP), NiMoOx/mesoporous carbon-long-rod (NiMoOx/MC-LR), and NiMoOx/mesoporous carbon-spherical (NiMoOx/MC-SP) with long mesochannels and relatively less surface area exhibited poor catalytic performance. The bifunctional mechanism or electronic synergistic effects of Ni and Mo species enhanced their catalytic performance. A good balance between MoOx and metallic Ni (NiMoOx/MC-PL-450) was found to be suitable for the reduction of 4-NP.
- Li, Shuna,Lv, Yipin,Song, Guolong,Li, Cuncheng,Gao, Daowei,Chen, Guozhu
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p. 4571 - 4582
(2019/02/26)
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- Highly Selective and Solvent-Dependent Reduction of Nitrobenzene to N-Phenylhydroxylamine, Azoxybenzene, and Aniline Catalyzed by Phosphino-Modified Polymer Immobilized Ionic Liquid-Stabilized AuNPs
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Gold nanoparticles stabilized by phosphine-decorated polymer immobilized ionic liquids (AuNP@PPh2-PIILP) is an extremely efficient multiproduct selective catalyst for the sodium borohydride-mediated reduction of nitrobenzene giving N-phenylhydroxylamine, azoxybenzene, or aniline as the sole product under mild conditions and a very low catalyst loading. The use of a single nanoparticle-based catalyst for the partial and complete reduction of nitroarenes to afford three different products with exceptionally high selectivities is unprecedented. Under optimum conditions, thermodynamically unfavorable N-phenylhydroxylamine can be obtained as the sole product in near quantitative yield in water, whereas a change in reaction solvent to ethanol results in a dramatic switch in selectivity to afford azoxybenzene. The key to obtaining such a high selectivity for N-phenylhydroxylamine is the use of a nitrogen atmosphere at room temperature as reactions conducted under an inert atmosphere occur via the direct pathway and are essentially irreversible, while reactions in air afford significant amounts of azoxy-based products by virtue of competing condensation due to reversible formation of N-phenylhydroxylamine. Ultimately, aniline can also be obtained quantitatively and selectively by adjusting the reaction temperature and time accordingly. Introduction of PEG onto the polyionic liquid resulted in a dramatic improvement in catalyst efficiency such that N-phenylhydroxylamine could be obtained with a turnover number (TON) of 100000 (turnover frequency (TOF) of 73000 h-1, with >99% selectivity), azoxybenzene with a TON of 55000 (TOF of 37000 h-1 with 100% selectivity), and aniline with a TON of 500000 (TOF of 62500 h-1, with 100% selectivity). As the combination of ionic liquid and phosphine is required to achieve high activity and selectivity, further studies are currently underway to explore whether interfacial electronic effects influence adsorption and thereby selectivity and whether channeling of the substrate by the electrostatic potential around the AuNPs is responsible for the high activity. This is the first report of a AuNP-based system that can selectively reduce nitroarenes to either of two synthetically important intermediates as well as aniline and, in this regard, is an exciting discovery that will form the basis to develop a continuous flow process enabling facile scale-up.
- Doherty, Simon,Knight, Julian G.,Backhouse, Tom,Summers, Ryan J.,Abood, Einas,Simpson, William,Paget, William,Bourne, Richard A.,Chamberlain, Thomas W.,Stones, Rebecca,Lovelock, Kevin R. J.,Seymour, Jake M.,Isaacs, Mark A.,Hardacre, Christopher,Daly, Helen,Rees, Nicholas H.
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p. 4777 - 4791
(2019/05/17)
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- A New Route to Cyclohexanone using H2CO3 as a Molecular Catalytic Ligand to Boost the Thorough Hydrogenation of Nitroarenes over Pd Nanocatalysts
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Carbon dioxide has been important in green chemistry, especially in catalytic and chemical engineering applications. While exploring CO2 to produce cyclohexanone for nylon or nylon 66 that is currently produced with low yields using harsh catalytic methods, we made the exciting discovery that carbonic acid, generated from dissolved CO2 in water, was utilized as molecular catalytic ligand to produce cyclohexanone via the hydrogenation of nitrobenzene in aqueous solution that uses Pd catalysts with a total yield higher than 90 %. Importantly, the gaseous nature of catalytic ligand H2CO3 profoundly simplifies post-catalysis cleanup unlike liquid or solid catalysts. This new green catalysis strategy demonstrated the universality for hydrogenation of aromatic compounds like aniline and N-methylaniline and could be broadly applicable in other catalytic field like artificial photosynthesis and electrocatalytic organic synthesis.
- Zhao, Tian-Jian,Zhang, Jun-Jun,Zhang, Bing,Liu, Yong-Xing,Lin, Yun-Xiao,Wang, Hong-Hui,Su, Hui,Li, Xin-Hao,Chen, Jie-Sheng
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p. 2837 - 2842
(2019/05/27)
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- A switchable-selectivity multiple-interface Ni-WC hybrid catalyst for efficient nitroarene reduction
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Selective reduction of nitroarenes is extremely valuable in industrial chemical production. The main reduced products are usually aniline derivatives obtained using single-component noble- or transition-metal catalysts; however, other important products such as hydrazobenzene derivatives always involve in harsh conditions and multiple reaction steps. Here, we realize an unexpected switchable reduction of nitroarenes into aniline or hydrazobenzene derivatives with high yield and selectivity just by controlling the molar ratio of nitroarenes to N2H4·H2O with a nickel–tungsten carbide composite nanocatalyst loaded on carbon (Ni-WC/C). A series of control experiments and density functional theory (DFT) calculations indicate that the multiple interfaces between Ni and WC can induce a synergistic effect, significantly modulating the electronic structure of the Ni-WC/C catalyst, and endowing the catalyst with switchable selectivity and high activity for the reduction of nitroarenes by hydrogenation. This synergistic multi-interfacial catalyst may offer a new way to design and explore highly efficient and selective catalysts for the controllable reduction of nitroarenes and similar hydrogenation reactions.
- Ma, Yuanyuan,Lang, Zhongling,Du, Jing,Yan,Wang, Yonghui,Tan, Huaqiao,Khan, Shifa Ullah,Liu, Yang,Kang, Zhenhui,Li, Yangguang
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p. 174 - 182
(2019/08/06)
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- Selective Hydrogenation by Carbocatalyst: The Role of Radicals
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The selective hydrogenation of the nitro moiety is a difficult task in the presence of other reducible functional groups such as alkenes or alkynes. We show that the carbon-based (metal-free) catalyst can be used to selectively reduce substituted nitro groups using H2 as a reducing agent, providing a great potential to replace noble-metal catalysts and contributing to simple and greener strategies for organic synthesis.
- Ahmad, Muhammad Sohail,He, Huixin,Nishina, Yuta
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supporting information
p. 8164 - 8168
(2019/10/16)
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- Selective Synthesis of Primary Anilines from NH3 and Cyclohexanones by Utilizing Preferential Adsorption of Styrene on the Pd Nanoparticle Surface
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Dehydrogenative aromatization is one of the attractive alternative methods for directly synthesizing primary anilines from NH3 and cyclohexanones. However, the selective synthesis of primary anilines is quite difficult because the desired primary aniline products and the cyclohexanone substrates readily undergo condensation affording the corresponding imines (i.e., N-cyclohexylidene-anilines), followed by hydrogenation to produce N-cyclohexylanilines as the major products. In this study, primary anilines were selectively synthesized in the presence of supported Pd nanoparticle catalysts (e.g., Pd/HAP, HAP=hydroxyapatite, Ca10(PO4)6(OH)2) by utilizing competitive adsorption unique to heterogeneous catalysis; in other words, when styrene was used as a hydrogen acceptor, which preferentially adsorbs on the Pd nanoparticle surface in the presence of N-cyclohexylidene-anilines, various structurally diverse primary anilines were selectively synthesized from readily accessible NH3 and cyclohexanones. The Pd/HAP catalyst was reused several times though its catalytic performance gradually declined.
- Koizumi, Yu,Jin, Xiongjie,Yatabe, Takafumi,Miyazaki, Ray,Hasegawa, Jun-ya,Nozaki, Kyoko,Mizuno, Noritaka,Yamaguchi, Kazuya
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supporting information
p. 10893 - 10897
(2019/07/12)
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- Ru-Catalyzed Deoxygenative Transfer Hydrogenation of Amides to Amines with Formic Acid/Triethylamine
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A ruthenium(II)-catalyzed deoxygenative transfer hydrogenation of amides to amines using HCO2H/NEt3 as the reducing agent is reported for the first time. The catalyst system consisting of [Ru(2-methylallyl)2(COD)], 1,1,1-tris(diphenylphosphinomethyl) ethane (triphos) and Bis(trifluoromethane sulfonimide) (HNTf2) performed well for deoxygenative reduction of various secondary and tertiary amides into the corresponding amines in high yields with excellent selectivities, and exhibits high tolerance toward functional groups including those that are reduction-sensitive. The choice of hydrogen source and acid co-catalyst is critical for catalysis. Mechanistic studies suggest that the reductive amination of the in situ generated alcohol and amine via borrowing hydrogen is the dominant pathway. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Xu, Xin,Zhao, Haoqiang,Han, Jiahong,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 3800 - 3806
(2019/07/12)
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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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- Unclicking of thioureas: Base catalyzed elimination of anilines and isothiocyanates from thioureas
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Bisaromatic thioureas are widely used in e.g. asymmetric organocatalysis and considered to be robust compounds. Herein we show, in strong contrast to common notion, that thioureas dissociate to amines and isothiocyanates in a base catalyzed reaction under mild conditions. This ‘unclicking’ process can occur in the presence of weak organic bases even at moderate temperatures. The influence of the substituents at the aromatic rings of the thiourea on the regioselectivity of this unclicking process is also shown.
- Vlatkovi?, Matea,Feringa, Ben L.
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p. 2188 - 2192
(2019/03/05)
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- Simple Nickel Salts for the Amination of (Hetero)aryl Bromides and Iodides with Lithium Bis(trimethylsilyl)amide
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Recent developments in the chemistry of C-N bond formation and the synthesis of anilines have allowed for the use of first-row transition metals to catalyze these transformations. Much of the progress in this area has been driven by comprehensive screening for privileged/tailored ligands, which can be costly and not readily available in a research laboratory setting. In this communication we report a protocol in which simple nickel salts catalyze the C-N cross-coupling reaction between (hetero)aryl bromides and iodides with lithium bis(trimethylsilyl)amide without the need for any additive ligand. This method is amenable to low nickel catalyst loadings (1%) as well as gram-scale reactions. Because of the good functional group tolerance and compatibility with heterocyclic moieties, this method is useful for academic laboratory settings where access to tailored ligands and noble-metal catalysts could be challenging.
- Martinez, Gabriel Espinosa,Nugent, Joseph W.,Fout, Alison R.
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supporting information
p. 2941 - 2944
(2018/09/21)
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- Preparation and Characterization of an Efficient Nano-Inorganic Composite of CuO/ZnO/Al2O3 for the Catalytic Amination of Aryl Halides in Aqueous Conditions
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In this research, an efficient recyclable nano-inorganic composite of CuO/ZnO/Al2O3 (CuO/ZnO/Al2O3 nanocatalyst) is prepared, characterized and used for the amination of aryl halides with aqueous ammonia in water. The catalyst was prepared by co-precipitation method and characterized by various techniques such as the X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy, and brunauer–Emmett–Teller surface area analysis. Various aryl halides reacted with aqueous ammonia and corresponding products were obtained in high yields. CuO/ZnO/Al2O3 nanocatalyst as an efficient stable catalyst is recyclable up to five consecutive runs by simple filtration. Graphical Abstract: An efficient recyclable nano-inorganic composite of CuO/ZnO/Al2O3 (CuO/ZnO-Al2O3 nanocatalyst) is prepared, characterized and used for the amination of aryl halides with aqueous ammonia in water. [Figure not available: see fulltext.].
- albadi, Jalal,Jalali, Mehdi,Samimi, Heshmat Allah
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p. 3750 - 3756
(2018/10/15)
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- STABILIZATION OF ACTIVE METAL CATALYSTS AT METAL-ORGANIC FRAMEWORK NODES FOR HIGHLY EFFICIENT ORGANIC TRANSFORMATIONS
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Metal-organic framework (MOFs) compositions based on post?synthetic metalation of secondary building unit (SBU) terminal or bridging OH or OH2 groups with metal precursors or other post-synthetic manipulations are described. The MOFs provide a versatile family of recyclable and reusable single-site solid catalysts for catalyzing a variety of asymmetric organic transformations, including the regioselective boryiation and siiylation of benzyiic C—H bonds, the hydrogenation of aikenes, imines, carbonyls, nitroarenes, and heterocycles, hydroboration, hydrophosphination, and cyclization reactions. The solid catalysts can also be integrated into a flow reactor or a supercritical fluid reactor.
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Paragraph 0354-0356; 0359
(2019/01/07)
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- Preparation method of aniline compound
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The invention discloses a preparation method of an aniline compound. The preparation method is simple in operation, uses iron powder as a reducing agent, concentrated sulfuric acid as a catalyst, andthe raw materials are easily obtained. According to the method, Fe is an electron donor, and a concentrated hydrochloric acid is added into an alcohol solution to maintain the presence of Fe ions in asystem, the reaction is more rapid. In addition, in the preparation method provided by the invention, the preparation process is relatively simple, the input cost of the reaction is low, the waste residue generated by the reaction is more easily separated, and by combing a step of recovery filtrate and a step of concentration, a solvent recovery method is simple, and at the same time, a reactionproduct is pure, and reaction yield is high.
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Paragraph 0047; 0051; 0053; 0055
(2018/06/26)
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- Preparation of Well-Ordered Mesoporous-Silica-Supported Ruthenium Nanoparticles for Highly Selective Reduction of Functionalized Nitroarenes through Transfer Hydrogenation
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MCM-41-type mesoporous silica (OMS-IL) was prepared by using an ionic liquid (1-hexadecyl-3-methylimidazolium bromide) as a template. The XRD and TEM results demonstrated that OMS-IL was more stable than the MCM-41 material. Ru nanoparticles were supported on OMS-IL (Ru/OMS-IL) by impregnating OMS-IL with a RuCl3 aqueous solution, and the resulting material was used for the selective reduction of nitroarenes. The effects of the components of the catalysts and the reaction conditions on the catalytic behavior of the prepared catalysts were investigated in detail. Ru/OMS-IL exhibited high catalytic activity and chemoselectivity for the reduction of various substituted nitroarenes to the corresponding aromatic amines in ethanol with hydrazine hydrate as a hydrogen donor under mild conditions. The Ru/OMS-IL catalysts were highly stable and could easily be recovered by simple filtration over at least six recycling reactions without any observable loss in catalytic performance.
- Wei, Ning,Zou, Xiujing,Huang, Haigen,Wang, Xueguang,Ding, Weizhong,Lu, Xionggang
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supporting information
p. 209 - 214
(2018/01/26)
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- Nitrogen-doped graphene-activated metallic nanoparticle-incorporated ordered mesoporous carbon nanocomposites for the hydrogenation of nitroarenes
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Herein, nanoscale metallic nanoparticle-incorporated ordered mesoporous carbon catalysts activated by nitrogen-doped graphene (NGr) were fabricated via an efficient multi-component co-assembly of a phenolic resin, nitrate, acetylacetone, the nitrogen-containing compound 1,10-phenanthroline, and Pluronic F127, followed by carbonization. The obtained well-dispersed nitrogen-doped graphene-activated transition metal nanocatalysts possess a 2-D hexagonally arranged pore structure with a high surface area (~500 m2 g-1) and uniform pore size (~4.0 nm) and show excellent activity for the selective hydrogenation-reduction of substituted nitroarenes to anilines in an environmentally friendly aqueous solution. The high catalytic performance and durability is attributed to the synergistic effects among the components, the unique structure of the nitrogen-doped graphene layer-coated metallic nanoparticles, and electronic activation of the doped nitrogen.
- Huang, Haigen,Wang, Xueguang,Sheng, Yao,Chen, Chenju,Zou, Xiujing,Shang, Xingfu,Lu, Xionggang
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p. 8898 - 8909
(2018/03/08)
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- N-doped graphitic carbon-improved Co-MoO3 catalysts on ordered mesoporous SBA-15 for chemoselective reduction of nitroarenes
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Metallic Co-MoO3 catalysts supported on ordered mesoporous SBA-15 were first prepared through in situ reaction of SBA-15-supported Co-Mo oxides with 1,10-phenanthroline. The resulting Co-MoO3/NC@SBA-15 catalysts with N-doped carbon (NC) exhibited high catalytic activity and chemoselectivity for selective reduction of various functionalized nitroarenes to the corresponding arylamines in ethanol with hydrazine hydrate at near room temperature (30 °C). For reduction of all tested substrates (28 examples), the catalyst could afford a conversion of >99% and arylamine selectivity of >99%. The excellent catalytic performance of the Co-MoO3/NC@SBA-15 was attributed to the Co-Nχ(C)-Mo active sites generated through the interaction between the surface Co-Nχ(C) and MoO3 species, promoting the dissociation of hydrazine molecule into the active H* species for the reduction of nitro groups. After the seventh cycle for reduction of 4-methoxylnitrobenzene, the 2%Co-MoO3/NC@SBA-15 showed little change in catalytic performance, textural properties, size and dispersion of metal species and valence states of elements, indicating high stability and recyclability.
- Huang, Haigen,Liang, Xiangcheng,Wang, Xueguang,Sheng, Yao,Chen, Chenju,Zou, Xiujing,Lu, Xionggang
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p. 127 - 137
(2018/05/04)
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- Enhanced catalytic performance of cobalt nanoparticles coated with a N,P-codoped carbon shell derived from biomass for transfer hydrogenation of functionalized nitroarenes
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The development of abundantly available base metal catalysts for organic transformations remains an important goal of chemical research. Herein, we report the first facile fabrication of active, inexpensive, and reusable cobalt nanoparticles (NPs) coated with a N,P-codoped carbon shell derived from naturally renewable biomass and earth-abundant, low-cost cobalt salt and PPh3. The entire process is operationally simple, straightforward, cost-effective and environmentally benign and can be used in mass production for practical application. The resultant catalysts allow for highly efficient and selective transfer hydrogenation of functionalized nitroarenes to the corresponding anilines using formic acid or ammonium formate as the hydrogen donor. Uniformly incorporated N and P into the carbon lattices exhibited synergistic effects with the encapsulated Co NPs to engineer the structure and composition of the catalyst, thereby substantially boosting the catalytic efficiency. The most active catalyst Co@NPC-800 exhibited outstanding activity and exclusive selectivity for the reduction of functionalized nitroarenes to anilines, especially those decorated with readily reducible functional groups. The catalyst demonstrated high stability and can be easily separated by using an external magnet for successive reuses without significant loss in both activity and selectivity.
- Duan, Yanan,Song, Tao,Dong, Xiaosu,Yang, Yong
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supporting information
p. 2821 - 2828
(2018/06/29)
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- Aminobenzotrifluoride solvent-free hydrogenation reduction process
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The invention relates to an aminobenzotrifluoride solvent-free hydrogenation reduction process and belongs to the field of pesticide chemical product preparation methods. The process mainly comprisesthe following steps: putting a raw material, namely nitryl benzotrifluoride, into a reaction kettle, performing a hydrogenation reduction reaction under conditions that no solvent is used and raney nickel is adopted as a catalyst, after the reaction is completed, cooling, filtering at normal pressure, recycling the catalyst, and performing negative pressure distillation on filtrate, thereby obtaining aminobenzotrifluoride. The whole process is carried out under a solvent-free process condition, so that emission of organic matters in the conventional production process is reduced; the consequence that a carbaryl byproduct is generated from reactions of solvents such as methanol with reduced amino is avoided, so that the product purity can be improved; compared with a conventional solvent method, the process is relatively low in temperature, relatively low in energy consumption, low in production cost and beneficial to energy conservation and emission reduction.
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Paragraph 0024; 0026; 0027; 0028; 0030; 0032
(2018/10/02)
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- Thermal azide-Alkene cycloaddition reactions: straightforward multi-gram access to Δ2-1,2,3-Triazolines in deep eutectic solvents
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The multi-gram synthesis of a wide range of 1,2,3-Triazolines via azide-Alkene cycloaddition reactions in a Deep Eutectic Solvent (DES) is reported. The role of DES in this transformation as well as the origin of the full product distribution was studied with an experimental/computational-DFT approach.
- Sebest, Filip,Casarrubios, Luis,Rzepa, Henry S.,White, Andrew J. P.,Díez-González, Silvia
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p. 4023 - 4035
(2018/09/11)
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- O-aminotrifluorotoluene solvent-free hydrogenation reduction technology
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The invention relates to an o-aminotrifluorotoluene solvent-free hydrogenation reduction technology belonging to the field of preparation methods of pesticide chemical products. The technology mainlycomprises the following steps: adding raw material nitryl trifluorotoluene into a reduction reaction kettle, carrying out hydrogenation reduction reaction under the conditions that no solvent is usedand raney nickel is taken as a catalyst, after the reaction is finished, cooling, filtering at normal pressure and recycling the catalyst, and carrying out negative pressure rectification on filtrate,so that o-aminotrifluorotoluene can be obtained. The whole process adopts the solvent-free technological condition, and discharge of organic matters in the traditional production process is reduced;the defect that solvents such as methanol react with reduced amino and carbaryl byproducts are generated is overcome, and product purity is improved; and compared with an existing solvent method, temperature is relatively low, energy consumption is relatively low, production cost is reduced, and energy conservation and discharge reduction are facilitated.
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Paragraph 0011; 0020-0025
(2018/09/11)
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- Preparation method of trifluoromethylamine
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The invention relates to a preparation method of trifluoromethylamine. The method includes the following steps that aromatic amine shown in the formula (1) and a trifluoromethyl reagent shown in the formula (2) react in a solvent under the condition that an alkali and/or nickel compound exists, and the trifluoromethylamine compound shown in the formula (3) is generated. According to the preparation method of trifluoromethylamine, aromatic amine and 1-trifluoromethyl-1,2-iodobenzoyl-3(H)-ketone serve as raw materials and react under the condition that the alkali and/or nickel compound exists through the amino positioning effect on aromatic nucleus. The synthesis steps of the method are simple, the cost of the raw materials is low, the production cost of trifluoromethylamine can be greatly reduced, and large-scale industrialized production is promoted.
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Paragraph 0023-0026; 0027-0045; 0046-0056
(2018/09/28)
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- Nickel-Catalyzed Direct C-H Trifluoromethylation of Free Anilines with Togni's Reagent
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An efficient nickel-catalyzed C-H trifluoromethylation for the synthesis of trifluoromethylated free anilines using Togni's reagent has been developed. This approach exhibits a good functional group tolerance, good regioselectivity, and chemoselectivity under mild conditions. The newly developed economical one-step method is a better alternative to synthesize trifluoromethylated free anilines.
- Gao, Xianying,Geng, Yang,Han, Shuaijun,Liang, Apeng,Li, Jingya,Zou, Dapeng,Wu, Yusheng,Wu, Yangjie
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supporting information
p. 3732 - 3735
(2018/07/22)
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- Direct ortho-Selective Amination of 2-Naphthol and Its Analogues with Hydrazines
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Described herein is a regioselective ortho-amination of 2-naphthol and its analogues with substituted hydrazines. It provides a direct methodology for the synthesis of N-arylaminated naphthol derivatives without the formation of related 1,1′-biaryl-2,2′-diamine or carbazole byproducts. Specifically, using N,N-disubstituted hydrazine precursors, N-unsubstituted ortho-aminated derivatives and related secondary amines can be formed in ethylene glycol in moderate to excellent yields. Variation of substrates to N,N′-diarylhydrazines and N-methyl-N,N′-diarylhydrazines led to N-aryl-1-amino-2-naphthol compounds. It is noted that biologically interesting indazole motifs can be facilely created by the reaction of N,N′-dialkylhydrazines with 2-naphthols. These ortho-amination reactions have the advantage of one-pot operation without the use of transition metal catalysts.
- Jia, Lei,Tang, Qiang,Luo, Meiming,Zeng, Xiaoming
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p. 5082 - 5091
(2018/05/15)
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- Copper-mediated reduction of azides under seemingly oxidising conditions: Catalytic and computational studies
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The reduction of aryl azides in the absence of an obvious reducing agent is reported. Careful catalyst design led to the production of anilines in the presence of water and air. The reaction medium (toluene/water) is crucial for the success of the reaction, as DFT calculations support the formation of benzyl alcohol as the oxidation product. A singular catalytic cycle is presented for this transformation based on four key steps: nitrene formation through nitrogen extrusion, formal oxidative addition of water, C(sp3)-H activation of toluene and reductive elimination.
- Zelenay, Benjamin,Besora, Maria,Monasterio, Zaira,Ventura-Espinosa, David,White, Andrew J. P.,Maseras, Feliu,Díez-González, Silvia
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p. 5763 - 5773
(2018/11/24)
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- A practical and highly efficient transfer hydrogenation of aryl azides using a [Ru(p-cymene)Cl2]2 catalyst and sodium borohydride
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Various aniline derivatives were synthesized by selective reduction of aryl azides in the presence of a dichloro(p-cymene)ruthenium(II) dimer ([Ru(p-cymene)Cl2]2) via hydrolysis of sodium borohydride. The hydrogenation reactions were carried out in aqueous media at room temperature. Most of the reactions were completed within 10 min with quantitative yields.
- Kilbas, Benan,Yilmaz, Yunus Emre,Ergen, Sinem
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p. 880 - 883
(2018/08/21)
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- Visible-light-mediated direct perfluoroalkylation and trifluoromethylation of free anilines
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A mild, operationally simple method for direct perfluoroalkylation and trifluoromethylation of anilines through visible-light-mediated photoredox catalysis from broadly available perfluoroalkyl iodides and free anilines is described. The method provides a facile route for application in drug discovery and development.
- He, Chun-Yang,Gu, Ji-Wei,Zhang, Xingang
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supporting information
p. 3939 - 3941
(2017/09/21)
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- Single-Site Cobalt Catalysts at New Zr12(μ3-O)8(μ3-OH)8(μ2-OH)6 Metal-Organic Framework Nodes for Highly Active Hydrogenation of Nitroarenes, Nitriles, and Isocyanides
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We report here the synthesis of a robust and porous metal-organic framework (MOF), Zr12-TPDC, constructed from triphenyldicarboxylic acid (H2TPDC) and an unprecedented Zr12 secondary building unit (SBU): Zr12(μ3-O)8(μ3-OH)8(μ2-OH)6. The Zr12-SBU can be viewed as an inorganic node dimerized from two commonly observed Zr6 clusters via six μ2-OH groups. The metalation of Zr12-TPDC SBUs with CoCl2 followed by treatment with NaBEt3H afforded a highly active and reusable solid Zr12-TPDC-Co catalyst for the hydrogenation of nitroarenes, nitriles, and isocyanides to corresponding amines with excellent activity and selectivity. This work highlights the opportunity in designing novel MOF-supported single-site solid catalysts by tuning the electronic and steric properties of the SBUs.
- Ji, Pengfei,Manna, Kuntal,Lin, Zekai,Feng, Xuanyu,Urban, Ania,Song, Yang,Lin, Wenbin
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p. 7004 - 7011
(2017/05/31)
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- Highly chemoselective reduction of nitroarenes over non-noble metal nickel-molybdenum oxide catalysts
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The chemoselective reduction of nitroarenes is an important transformation for the production of arylamines, which are the primary intermediates in the synthesis of pharmaceuticals, agrochemicals and dyes. Heterogeneous non-noble metal nickel-molybdenum oxide catalysts supported on ordered mesoporous silica SBA-15 (Ni-MoO3/CN@SBA-15) were prepared for the first time by treating SBA-15-supported nickel-molybdenum oxide materials with 1,10-phenanthroline, and exhibited unprecedented catalytic activity and chemoselectivity for the reduction of various substituted nitroarenes to the corresponding aromatic amines in ethanol with hydrazine hydrate as a hydrogen donor under mild conditions owing to the synergistic effect of metal Ni and MoO3 species, affording excellent yields of >99% within very short reaction periods (≤60 min). The Ni-MoO3/CN@SBA-15 catalysts were highly stable and could easily be recovered by simple filtration or by an external magnetic field for at least ten recycling reactions without any observable loss of catalytic performance or leaching of metal components.
- Huang, Haigen,Wang, Xueguang,Li, Xu,Chen, Chenju,Zou, Xiujing,Ding, Weizhong,Lu, Xionggang
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p. 809 - 815
(2017/08/15)
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