455-14-1Relevant articles and documents
Ionic liquids as new media for electrophilic trifluoromethylation reactions
Pégot, Bruce,Macé, Yohan,Urban, Céline,Diter, Patrick,Blazejewski, Jean-Claude,Magnier, Emmanuel
, p. 156 - 159 (2012)
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.
Chemo-, site-selective reduction of nitroarenes under blue-light, catalyst-free conditions
Liang, Yong,Lu, Changsheng,Lu, Shuo,Ma, Jiawei,Ren, Hongyuan,Wang, Bin,Xu, Jingkai,Yan, Hong
supporting information, p. 2420 - 2424 (2021/12/13)
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.
Porous polymeric ligand promoted copper-catalyzed C-N coupling of (hetero)aryl chlorides under visible-light irradiation
Wang, Erfei,Chen, Kaixuan,Chen, Yinan,Zhang, Jiawei,Lin, Xinrong,Chen, Mao
, p. 17 - 21 (2020/11/04)
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.]
Highly efficient N-doped carbon supported FeSx-Fe2O3 catalyst for hydrogenation of nitroarenes via pyrolysis of sulfurized N,Fe-containing MOFs
Li, Xuewei,She, Wei,Wang, Jing,Li, Weizuo,Li, Guangming
, (2021/05/18)
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.
Photocatalytic reduction of nitroaromatics into anilines using CeO2-TiO2 nanocomposite
Chen, Changdong,Lu, Caiyun,Sun, Chengxin,Wang, Fangfang,Yin, Zhengfeng
, (2021/08/19)
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.
Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
supporting information, p. 1618 - 1629 (2021/01/25)
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.
A highly efficient LaOCl supported Fe-Fe3C-based catalyst for hydrogenation of nitroarenes fabricated by coordination-assisted pyrolysis
Li, Guangming,Li, Weizuo,Li, Xuewei,She, Wei,Wang, Jing
, p. 4627 - 4635 (2021/07/12)
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.
Sustainable and recyclable palladium nanoparticles–catalyzed reduction of nitroaromatics in water/glycerol at room temperature
Chen, Jin,Dai, Bencai,Liu, Changchun,Shen, Zhihao,Zhao, Yongde,Zhou, Yang
, p. 540 - 544 (2020/07/14)
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.
Efficient hydrogenation catalyst designing via preferential adsorption sites construction towards active copper
Dai, Xingchao,He, Dongcheng,Li, Teng,Shi, Feng,Wang, Hongli,Wang, Tao,Wang, Xinzhi
, p. 397 - 406 (2021/07/21)
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.
Cu-Catalyzed Cross-Coupling of Nitroarenes with Aryl Boronic Acids to Construct Diarylamines
Guan, Xinyu,Zhu, Haoran,Driver, Tom G.
, p. 12417 - 12422 (2021/10/12)
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.
