- A quinoline alkaloid rich Quisqualis indica floral extract enhances the bioactivity
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A volatile alkaloid quinoline-4-carbonitrile (QCN) was isolated from the floral extract of Quisqualis indica. Major compounds were trans-linalool oxide (1.0, 4.5%), methyl benzoate (1.0, 4.0%), 2,2,6-trimethyl-6-vinyl-tetrahydropyran-3-one (7.4, 17.8%), 2,2,6-trimethyl-6-vinyl-tetrahydropyran-3-ol (1.0, 1.2%), (E,E)-α-farnesene (29.1, 16.1%), QCN (5.7, 1.3%) in live and picked flowers, respectively. Flower compositions were altered due to change in enzymatic reaction at the time of picking. Some rearrangements of oxygenated terpenoids occurred in the process of hydrodistillation to obtain essential oil. Chemical synthesis of QCN and its selectively reduced products derived from QCN were prepared through green reaction process. The catalytic modification of QCN has produced quinoline-4-methylamine; the later compound has shown enhanced bio-activities. QCN and floral extract (absolute) have shown potential anti-inflammatory and antioxidant activities. Besides, floral absolute has shown significant anti-inflammatory and antioxidant activities due to improved QCN (19.7%) content to synergize amongst terpenoids and benzenoids as compared to the essential oil with 1.1% of QCN.
- Rout, Prasant Kumar,Kumar, Prashant,Rao, Y. Ramachandra,Kumar, Anant,Bawankule, Dnyaneshwar U.,Singh, Ruchi,Singh, Kijay Bahadur,Chanotiya, Chandan Singh,Naik
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Read Online
- Explaining the Size Dependence in Platinum-Nanoparticle-Catalyzed Hydrogenation Reactions
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Hydrogenation reactions are industrially important reactions that typically require unfavorably high H2pressure and temperature for many functional groups. Herein we reveal surprisingly strong size-dependent activity of Pt nanoparticles (PtNPs) in catalyzing this reaction. Based on unambiguous spectral analyses, the size effect has been rationalized by the size-dependent d-band electron structure of the PtNPs. This understanding enables production of a catalyst with size of 1.2 nm, which shows a sixfold increase in turnover frequency and 28-fold increase in mass activity in the regioselective hydrogenation of quinoline, compared with PtNPs of 5.3 nm, allowing the reaction to proceed under ambient conditions with unprecedentedly high reaction rates. The size effect and the synthesis strategy developed herein may provide a general methodology in the design of metal-nanoparticle-based catalysts for a broad range of organic syntheses.
- Bai, Licheng,Wang, Xin,Chen, Qiang,Ye, Yifan,Zheng, Haoquan,Guo, Jinghua,Yin, Yadong,Gao, Chuanbo
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Read Online
- Heterogeneous Hydrogenation of Quinoline Derivatives Effected by a Granular Cobalt Catalyst
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We communicate a convenient method for the pressure hydrogenation of quinolines in aqueous solution by using a particulate cobalt-based catalyst that is prepared in situ from simple Co(OAc)2 4H2O through reduction with abundant zinc powder. This catalytic protocol permits a brisk and atom-efficient access to a variety of 1,2,3,4-tetrahydroquinolines thereby relying solely on easy-to-handle reagents that are all readily obtained from commercial sources. Both the reaction setup assembly and the autoclave charging procedure are conducted on the bench outside an inert-gas-operated containment system, thus rendering the overall synthesis time-saving and operationally very simple.
- Timelthaler, Daniel,Topf, Christoph
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p. 629 - 642
(2021/11/22)
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- Method for preparing tetrahydroquinoline compounds by catalytic hydrogenation of ruthenium catalyst
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The invention relates to a method for preparing tetrahydroquinoline compounds by catalytic hydrogenation of a ruthenium catalyst, which comprises the following steps: by using p-cymene ruthenium chloride dimer as a catalyst and hydrogen as a reducing agent, mixing the p-cymene ruthenium chloride dimer, phosphine ligand and quinoline compounds, and dissolving the mixture in an organic solvent to react, and carrying out post-treatment to obtain the tetrahydroquinoline derivative. Compared with the prior art, the method has the advantages of easily available raw materials, mild conditions, simpleoperation, atom economy, simple and green synthesis process, mild reaction conditions, excellent selectivity, high yield and good reaction universality, and has a wide application value in fine chemical intermediate synthesis.
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Paragraph 0034-0037
(2021/01/29)
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- Chemoselective and Tandem Reduction of Arenes Using a Metal–Organic Framework-Supported Single-Site Cobalt Catalyst
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The development of heterogeneous, chemoselective, and tandem catalytic systems using abundant metals is vital for the sustainable synthesis of fine and commodity chemicals. We report a robust and recyclable single-site cobalt-hydride catalyst based on a porous aluminum metal–organic framework (DUT-5 MOF) for chemoselective hydrogenation of arenes. The DUT-5 node-supported cobalt(II) hydride (DUT-5-CoH) is a versatile solid catalyst for chemoselective hydrogenation of a range of nonpolar and polar arenes, including heteroarenes such as pyridines, quinolines, isoquinolines, indoles, and furans to afford cycloalkanes and saturated heterocycles in excellent yields. DUT-5-CoH exhibited excellent functional group tolerance and could be reusable at least five times without decreased activity. The same MOF-Co catalyst was also efficient for tandem hydrogenation–hydrodeoxygenation of aryl carbonyl compounds, including biomass-derived platform molecules such as furfural and hydroxymethylfurfural to cycloalkanes. In the case of hydrogenation of cumene, our spectroscopic, kinetic, and density functional theory (DFT) studies suggest the insertion of a trisubstituted alkene intermediate into the Co–H bond occurring in the turnover limiting step. Our work highlights the potential of MOF-supported single-site base–metal catalysts for sustainable and environment-friendly industrial production of chemicals and biofuels.
- Akhtar, Naved,Begum, Wahida,Chauhan, Manav,Manna, Kuntal,Newar, Rajashree,Rawat, Manhar Singh
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supporting information
(2022/01/19)
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- Utilization of renewable formic acid from lignocellulosic biomass for the selective hydrogenation and/or N-methylation
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Lignocellulosic biomass is one of the most abundant renewable sources in nature. Herein, we have developed the utilization of renewable formic acid from lignocellulosic biomass as a hydrogen source and a carbon source for the selective hydrogenation and further N-methylation of various quinolines and the derivatives, various indoles under mild conditions in high efficiencies. N-methylation of various anilines is also developed. Mechanistic studies indicate that the hydrogenation occurs via a transfer hydrogenation pathway.
- Zhou, Chao-Zheng,Zhao, Yu-Rou,Tan, Fang-Fang,Guo, Yan-Jun,Li, Yang
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p. 4724 - 4728
(2021/09/06)
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- Homogeneous pressure hydrogenation of quinolines effected by a bench-stable tungsten-based pre-catalyst
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We report on an operationally simple catalytic method for the tungsten-catalyzed hydrogenation of quinolines through the use of the easily handled and self-contained precursor [WCl(η5-Cp)(CO)3]. This half sandwich complex is indefinitely storable on the bench in simple screw-capped bottles or stoppered flasks and can, if required, be prepared on a multi-gram scale while the actual catalytic transformations were performed in the presence of a Lewis acid in order to achieve both decent substrate conversions and product yields. The described method represents a facile and atom-efficient access to a variety of 1,2,3,4-tetrahydroquinolines that circumvents the use of cost-intensive and oxygen-sensitive phosphine ligands as well as auxiliary hydride reagents.
- Heizinger, Christian,Topf, Christoph,Vielhaber, Thomas
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p. 451 - 461
(2021/11/11)
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- Biogenic Synthesis of Gold Nanoparticles on a Green Support as a Reusable Catalyst for the Hydrogenation of Nitroarene and Quinoline
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Direct attachment of gold nanoparticles to a green support without the use of an external reducing agent and using it for removing toxic pollutants from wastewater, i. e., reduction of nitroarene to amine, are described. A novel approach involving the reduction of gold by the jute plant (Corchorus genus) stem-based (JPS) support itself to form nanoparticles (AuNPs) to be used as a catalytic system (‘dip-catalyst’) and its catalytic activity for the hydrogenation of series of nitroarenes in aqueous media are presented. AuNPs/JPS catalyst was characterized using SEM, UV-Vis, FTIR, TEM, XPS, and ICP-OES. Confined area elemental mapping exhibits uniform and homogeneous distribution of AuNPs on the support surface. TEM shows multi-faceted AuNPs in the range of 20–30 nm. The reactivity of AuNPs/JPS for the transfer hydrogenation of nitroarene as well as hydrogenation of quinoline under molecular H2 pressure was evaluated. Sodium borohydride, when used as the hydrogen source, demonstrates a high catalytic efficiency in the transfer hydrogenation reduction of 4-nitrophenol (4-NP). Quinoline is quantitatively and chemoselectively hydrogenated to 1,2,3,4-tetrahydroquinoline (py-THQ) using molecular hydrogen. Reusability studies show that AuNPs are stable on the support surface and their selectivity is not affected.
- Adeyeye Nafiu, Sodiq,Aziz, Abdul,Shaheen Shah, Syed,Shaikh, M. Nasiruzzaman
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p. 1956 - 1966
(2021/06/18)
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- Cu-Catalyzed Chemoselective Reduction of N-Heteroaromatics with NH3·BH3 in Aqueous Solution
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An efficient catalytic system was successfully developed on reduction of N-heteroaromatics with H3N?BH3 as hydrogen source in CuSO4 solution, featuring excellent chemoselectivity as well as very broad functional group tolerance. Various challenging substrates, such as OH-, NH2-, Cl-, Br-, etc., contained quinolines, quinoxalines, 1,5-naphthyridines and quinazolines were all reduced smoothly. Mechanistic studies suggested that [Cu-H] intermediate might be generated from NH3?BH3, which was believed to form with H3N?BH3 in CuSO4 solution.
- Gao, Chao,Xuan, Qingqing,Song, Qiuling
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supporting information
p. 2504 - 2508
(2021/07/31)
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- Catalytic Hydrogenation of Substituted Quinolines on Co–Graphene Composites
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A set of 20 composites was prepared by pyrolysis of Co2+ complexes with 1,10-phenanthroline, melamine and 1,2-diaminobenzene. These composites were tested as the catalysts for the hydrogenation of quinolines. As shown by powder X-ray diffraction and TEM, the composited contained Co particles of several dozen nm sizes. The composition (elements content), Raman spectra X-ray photoelectron spectra parameters of the composites were analyzed. It was found that there was no distinct factor that controlled the yield of 1,2,3,4-tetrahydroquinolines in the investigated process. The yields of the respective products were in the range 90–100 %. The three most active composites were selected for scale-up and hydrogenation of a series of substituted quinolines. Up to 97 % yield of 1,2,3,4-tetrahydroquinoline was obtained on a 50 g scale. Five representative substituted quinolines were synthesized on a 10–20 grams scale using the Co-containing composites as the catalysts.
- Asaula, Vitalii M.,Buryanov, Volodymyr V.,Solod, Bohdan Y.,Tryus, Daryna M.,Pariiska, Olena O.,Kotenko, Igor E.,Volovenko, Yulian M.,Volochnyuk, Dmitriy M.,Ryabukhin, Sergey V.,Kolotilov, Sergey V.
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p. 6616 - 6625
(2021/12/24)
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- Boric acid catalyzed chemoselective reduction of quinolines
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Boric acid promoted transfer hydrogenation of substituted quinolines to synthetically versatile 1,2,3,4-tetrahydroquinolines (1,2,3,4-THQs) was described under mild reaction conditions using a Hantzsch ester as a mild organic hydrogen source. This methodology is practical and efficient, where isolated yields are excellent and reducible functional groups are well tolerated in the N-heteroarene moiety. The reaction parameters and tentative mechanistic pathways are demonstrated by various control experiments and NMR studies. The present work can also be scaled up to obtain gram quantities and the utility of the developed process is illustrated by the transformation of 1,2,3,4-THQs into a series of biologically important molecules including the antiarrhythmic drug nicainoprol.
- Adhikari, Priyanka,Bhattacharyya, Dipanjan,Das, Animesh,Konwar, Monuranjan,Nandi, Sekhar,Sarmah, Bikash Kumar
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supporting information
p. 1214 - 1220
(2020/02/22)
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- Simple manganese carbonyl catalyzed hydrogenation of quinolines and imines
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Manganese-catalyzed hydrogenation of unsaturated molecules has made tremendous progresses recently benefiting from non-innocent pincer or bidentate ligands for manganese. Herein, we describe the hydrogenation of quinolines and imines catalyzed by simple manganese carbonyls, Mn2(CO)10 or MnBr(CO)5, thus eliminating the prerequisite pincer-type or bidentate ligands.
- Wang, Zelong,Chen, Lei,Mao, Guoliang,Wang, Congyang
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p. 1890 - 1894
(2020/03/04)
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- The Alkylation and Reduction of Heteroarenes with Alcohols Using Photoredox Catalyzed Hydrogen Atom Transfer via Chlorine Atom Generation
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Radical additions to heteroaromatic bases are frequently employed for the rapid synthesis of complex products using C–H functionalization strategies. The conditions that are commonly employed are typically harsh, routinely requiring stoichiometric oxidants and other additives. In search for milder reaction environments allowing late-stage functionalization, we present the alkylation of N-heteroarenes using primary alcohols and ethers as radical precursors, where the corresponding alkyl radical is formed via hydrogen atom transfer process with a photoredox catalyzed chlorine atom generation as HAT agent. Furthermore, we explore the reduction of the heteroarenes in moderate to high yields when using secondary alcohols.
- Zidan, Montserrat,Morris, Avery O.,McCallum, Terry,Barriault, Louis
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supporting information
p. 1453 - 1458
(2019/08/01)
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- Reversible aerobic oxidative dehydrogenation/hydrogenation of N-heterocycles over AlN supported redox cobalt catalysts
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N-heterocycles with quinoline and tetrahydroquinoline structures are highly important in pharmaceutical and chemical industries, and their highly efficient mutual transformations are vital but still challenging. In the present work, AlN supported redox cobalt catalysts (Co3O4/AlN and Co/AlN) were prepared, which could achieve the reversible aerobic oxidative dehydrogenation/hydrogenation of N-heterocycles with good performances. The catalytic performances were stem from the strong interaction between Co species with AlN support, which were confirmed by the characterizations of Raman, XPS, UV–vis DRS, and H2-TPR etc. Both of the catalysts showed good stabilities and reusabilities for the titled reactions. Besides, the gram-scale experiments achieved with good yields to corresponding products, revealing the present protocol possesses great potential applications in industry. The strategy of using redox Co-based catalyst not only provides a potential catalyst for the reversible hydrogenation/oxidative dehydrogenation reactions but also replenishes methods for constructing of other redox catalyst, especially with AlN as a carrier.
- He, Zhen-Hong,Sun, Yong-Chang,Wang, Kuan,Wang, Zhong-Yu,Guo, Pan-Pan,Jiang, Chong-Shan,Yao, Man-Qing,Li, Zhu-Hui,Liu, Zhao-Tie
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- SULFONYL-SUBSTITUTED BICYCLIC COMPOUND WHICH ACTS AS ROR INHIBITOR
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Provided is a sulfonyl-substituted bicyclic compound (A) which acts as a RORγ inhibitor, said compound has good RORγ inhibitory activity and is expected to be used for treating diseases mediated by a RORγ receptor in mammals.
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Paragraph 0483; 0484
(2020/08/16)
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- Visible Light Photocatalytic Synthesis of Tetrahydroquinolines Under Batch and Flow Conditions
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In this work, we describe the use of visible light and a photocatalytic system for the cyclization of iodoaryl vinyl derivatives to tetrahydroquinoline structures. The reaction proceeds under very mild conditions, tolerates different functional groups and more importantly, the method allows the synthesis of N-free tetrahydroquinolines from N-unprotected starting materials. In addition, the reaction can also be performed using flow-chemistry. Finally, a mechanistic proposal based on some mechanistic studies has been described.
- González-Mu?oz, Daniel,Nova-Fernández, José Luis,Martinelli, Ada,Pascual-Coca, Gustavo,Cabrera, Silvia,Alemán, José
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p. 5995 - 5999
(2020/09/17)
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- Cobalt-bridged secondary building units in a titanium metal-organic framework catalyze cascade reduction of N-heteroarenes
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We report here a novel Ti3-BPDC metal-organic framework (MOF) constructed from biphenyl-4,4′-dicarboxylate (BPDC) linkers and Ti3(OH)2 secondary building units (SBUs) with permanent porosity and large 1D channels. Ti-OH groups from neighboring SBUs point toward each other with an O-O distance of 2 ?, and upon deprotonation, act as the first bidentate SBU-based ligands to support CoII-hydride species for effective cascade reduction of N-heteroarenes (such as pyridines and quinolines) via sequential dearomative hydroboration and hydrogenation, affording piperidine and 1,2,3,4-tetrahydroquinoline derivatives with excellent activity (turnover number ~ 1980) and chemoselectivity.
- Feng, Xuanyu,Song, Yang,Chen, Justin S.,Li, Zhe,Chen, Emily Y.,Kaufmann, Michael,Wang, Cheng,Lin, Wenbin
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p. 2193 - 2198
(2019/02/20)
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- General and Chemoselective Copper Oxide Catalysts for Hydrogenation Reactions
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Copper oxide catalysts have been prepared by pyrolysis of copper acetate on aluminum oxide. The material resulting from pyrolysis at 800 °C allows for catalytic hydrogenations at low temperature of a variety of unsaturated compounds such as quinolines, alkynes, ketones, imines, and polycyclic aromatic hydrocarbons as well as nitroarenes with good activity and selectivity.
- Li, Wu,Cui, Xinjiang,Junge, Kathrin,Surkus, Annette-Enrica,Kreyenschulte, Carsten,Bartling, Stephan,Beller, Matthias
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p. 4302 - 4307
(2019/05/08)
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- Silver-Catalyzed Reduction of Quinolines in Water
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A ligand- and base-free silver-catalyzed reduction of quinolines and electron-deficient aromatic N-heteroarenes in water has been described. Mechanistic studies revealed that the effective reducing species was Ag-H. This versatile catalytic protocol provided facile, environmentally friendly, and practical access to a variety of 1,2,3,4-tetrahydroquinoline derivatives at room temperature.
- Wang, Yan,Dong, Baobiao,Wang, Zikun,Cong, Xuefeng,Bi, Xihe
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supporting information
p. 3631 - 3634
(2019/05/24)
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- Room temperature catalytic dehydrogenation of cyclic amines with the liberation of H2 using water as a solvent
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Catalytic dehydrogenation of cyclic amines, in particular partially saturated N-heterocycles to N-heterocyclic arenes, with the removal of molecular hydrogen as the sole byproduct in water is reported. This dehydrogenation reaction proceeds smoothly under very mild and benign conditions and operates at room temperature. This distinctive reactivity has been achieved under dual catalytic conditions by merging the visible-light active [Ru(bpy)3]2+ as the photoredox catalyst and a newly synthesized cobalt complex as the proton-reduction catalyst. A detailed mechanistic study (control experiments, electrochemical studies, UV-visible experiments) is presented for the present dual catalysis.
- Sahoo, Manoj K.,Balaraman, Ekambaram
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p. 2119 - 2128
(2019/04/26)
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- Method for conducting catalytic hydrogenation on nitrogen-containing unsaturated heterocyclic compound
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The invention provides a method for conducting catalytic hydrogenation on a nitrogen-containing unsaturated heterocyclic compound, and belongs to the technical field of catalytic hydrogenation. The provided method for conducting catalytic hydrogenation on the nitrogen-containing unsaturated heterocyclic compound comprises the following step: in the presence of hydrogen and a manganese catalyst, with the nitrogen-containing unsaturated heterocyclic compound as a substrate, carrying out a hydrogenation reaction. According to the method for conducting catalytic hydrogenation on the nitrogen-containing unsaturated heterocyclic compound, he adopted manganese catalyst is an NNP-type pincer manganese catalyst, has the advantages of being cheap, easy to obtain and low in toxicity compared with noble metal catalysts, has the advantages of being wide in substrate applicability and high in target product yield compared with an existing cheap metal iron catalyst or cobalt catalyst, and is higher in electron donating ability and smaller in steric hindrance compared with a PNP-type pincer manganese catalyst, and thus shows higher reaction activity in a series of hydrogenation reactions, and thetarget product yield is up to 99%.
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Paragraph 0094-0104
(2020/01/03)
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- Nanolayered Cobalt-Molybdenum Sulfides as Highly Chemo- and Regioselective Catalysts for the Hydrogenation of Quinoline Derivatives
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Herein, a general protocol for the preparation of a broad range of valuable N-heterocyclic products by hydrogenation of quinolines and related N-heteroarenes is described. Interestingly, the catalytic hydrogenation of the N-heteroarene ring is chemoselectively performed when other facile reducible functional groups, including alkenes, ketones, cyanides, carboxylic acids, esters, and amides, are present. The key to successful catalysis relies on the use of a nanolayered cobalt-molybdenum sulfide catalyst hydrothermally synthesized from earth-abundant metal precursors. This heterogeneous system displays a tunable composition of phases that allows for catalyst regeneration. Its catalytic activity depends on the composition of the mixed phase of cobalt sulfides, being higher with the presence of Co3S4, and could also be associated with the presence of transient Co-Mo-S structures that mainly vanish after the first catalytic run.
- Sorribes, Iván,Liu, Lichen,Doménech-Carbó, Antonio,Corma, Avelino
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p. 4545 - 4557
(2018/05/22)
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- Cu-catalyzed reduction of azaarenes and nitroaromatics with diboronic acid as reductant
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A ligand-free copper-catalyzed reduction of azaarenes with diboronic acid as reductant in an aprotic solvent under mild conditions has been developed. Most interestingly, the nitroazaarenes could be reduced exclusively to give the corresponding amines without touching the azaarene moieties. Furthermore, the reductive amination of aromatic nitro compounds and aromatic aldehydes has also been realized. A series of hydrogenated azaarenes and secondary amines were obtained with good functional group tolerance.
- Pi, Danwei,Zhou, Haifeng,Zhou, Yanmei,Liu, Qixing,He, Renke,Shen, Guanshuo,Uozumi, Yasuhiro
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p. 2121 - 2129
(2018/03/23)
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- Cyclometalated Half-Sandwich Iridium Complex for Catalytic Hydrogenation of Imines and Quinolines
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Several C,N-chelate cyclometalated half-sandwich iridium-based catalysts for imines and quinoline derivatives reduction have been prepared through metal-mediated C-H bond activation based on benzothiazole ligands. These iridium complexes exhibited high catalytic activity for hydrogenation of various types of imines with high yields. The most active catalyst was obtained from methoxyl substituted complex 2, showing the catalytic TOF value of 975 h-1 for the reduction of imine 6a. Additionally, these half-sandwich complexes also showed high efficiency for the catalytic hydrogenation of N-heterocyclic quinoline derivatives. Good catalytic activity was displayed for various kinds of substrates with either electron-donating or electron-withdrawing groups. Complexes 1-5 were fully characterized by NMR, IR, and elemental analysis. Molecular structures of complexes 1 and 4 were further confirmed by X-ray diffraction analysis.
- Yao, Zi-Jian,Lin, Nan,Qiao, Xin-Chao,Zhu, Jing-Wei,Deng, Wei
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p. 3883 - 3892
(2018/11/24)
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- Synthesis method of 1, 2, 3, 4-tetrahydroquinoline compound
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Belonging to the technical field of organic chemical synthesis, the invention discloses a synthesis method of a 1, 2, 3, 4-tetrahydroquinoline compound. The method adopts elemental iodine as the catalyst, uses borane as the reductant, and subjects a quinoline compound to catalytic reduction reaction, thus obtaining the product. Compared with the existing synthesis methods, the method has the greatest characteristics of use of cheap I2 as the catalyst, no need for metal to participate in reaction, mild reaction conditions, rapidity and high efficiency, high catalytic efficiency, simple operation, good selectivity, high product conversion rate up to 80% or more, is of great popularization and application value, and is beneficial to industrial production.
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Paragraph 0023; 0024; 0025; 0026
(2018/11/27)
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- A Practical and Chemoselective Ammonia-Free Birch Reduction
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A novel protocol for a significantly improved, practical, and chemoselective ammonia-free Birch reduction mediated by bench-stable sodium dispersions and recoverable 15-crown-5 ether is reported. A broad range of aromatic and heteroaromatic compounds is reduced with excellent yields.
- Lei, Peng,Ding, Yuxuan,Zhang, Xiaohe,Adijiang, Adila,Li, Hengzhao,Ling, Yun,An, Jie
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supporting information
p. 3439 - 3442
(2018/06/26)
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- Iodine catalyzed reduction of quinolines under mild reaction conditions
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A reduction of quinolines to synthetically versatile tetrahydroquinoline molecules with I2 and HBpin is described. In the presence of iodine (20 mol%) as a catalyst, reduction of quinolines and other N-heteroarenes proceeded readily with hydroboranes as the reducing reagents. The broad functional-group tolerance, good yields and mild reaction conditions imply high practical utility.
- Yang, Chun-Hua,Chen, Xixi,Li, Huimin,Wei, Wenbo,Yang, Zhantao,Chang, Junbiao
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supporting information
p. 8622 - 8625
(2018/08/06)
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- Novel electronic salt system and method for reducing unsaturated hydrocarbon compound
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The invention discloses an electronic salt system and a method for reducing unsaturated hydrocarbon compounds by using the electronic salt system, belongs to the field of organic synthesis, and solvesthe problems such as complicated operation, harsh conditions, easy generation of complex over-reduction products of methods for reducing the unsaturated hydrocarbon compounds in the prior art. An electron salt may be synthesized by an alkali metal reagent, an ether and an alcohol, the ether can be a crown ether or a cryptand; and the method adopts the electronic salt system, the unsaturated hydrocarbon compounds is reduced by the electronic salt system in an organic solvent. The method for reducing the unsaturated hydrocarbon compounds is used for reducing the unsaturated hydrocarbon compounds.
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Paragraph 0209-0213
(2018/09/08)
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- A robust iron catalyst for the selective hydrogenation of substituted (iso)quinolones
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By applying N-doped carbon modified iron-based catalysts, the controlled hydrogenation of N-heteroarenes, especially (iso)quinolones, is achieved. Crucial for activity is the catalyst preparation by pyrolysis of a carbon-impregnated composite, obtained from iron(ii) acetate and N-aryliminopyridines. As demonstrated by TEM, XRD, XPS and Raman spectroscopy, the synthesized material is composed of Fe(0), Fe3C and FeNx in a N-doped carbon matrix. The decent catalytic activity of this robust and easily recyclable Fe-material allowed for the selective hydrogenation of various (iso)quinoline derivatives, even in the presence of reducible functional groups, such as nitriles, halogens, esters and amides. For a proof-of-concept, this nanostructured catalyst was implemented in the multistep synthesis of natural products and pharmaceutical lead compounds as well as modification of photoluminescent materials. As such this methodology constitutes the first heterogeneous iron-catalyzed hydrogenation of substituted (iso)quinolones with synthetic importance.
- Sahoo, Basudev,Kreyenschulte, Carsten,Agostini, Giovanni,Lund, Henrik,Bachmann, Stephan,Scalone, Michelangelo,Junge, Kathrin,Beller, Matthias
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p. 8134 - 8141
(2018/11/20)
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- Aerobic oxidative dehydrogenation of N-heterocycles catalyzed by cobalt porphyrin
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An efficient catalytic procedure has been developed for the aerobic oxidative dehydrogenation of N-heterocycles by cobalt porphyrin in the absence of any additives. The catalytic system could tolerate various 1,2,3,4-tetrahydroquinoline derivatives and some other N-heterocycles. The corresponding N-heteroaromatics could be obtained in 59–86% yields. The mechanism investigation suggested that the aerobic oxidative dehydrogenation might proceed with imine intermediate through radical paths.
- Zhou, Weiyou,Chen, Dongwei,Sun, Fu'an,Qian, Junfeng,He, Mingyang,Chen, Qun
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supporting information
p. 949 - 953
(2018/02/09)
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- N-doped hierarchical porous carbon anchored tiny Pd NPs: A mild and efficient quinolines selective hydrogenation catalyst
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Chemoselective hydrogenation of quinolines is often subjected to the problems of leaching and poisoning of catalytic active site as well as harsh reaction conditions. Developing a novel and high-performance heterogeneous catalyst is of paramount importance yet a huge challenge. Herein, we report a facile and efficient strategy for preparing the large surface area and highly N-doped hierarchical porous carbon anchored tiny Pd NPs catalyst, in which the low-cost chitosan, nitrogen-rich ionic liquids are served as composite precursors and KZ molten salt as friendly pore-forming agent. And a series of Pd@CIL-T (C refers to chitosan, IL refers to ionic liquid, T = 600–900 °C) catalysts are successfully fabricated via pyrolyzing aforesaid composites at different temperatures followed by anchoring the highly dispersed and small-sized Pd NPs on their surface. Among all the prepared catalysts, Pd@CIL-900 exhibits the optimal catalytic performance towards the selective hydrogenation of quinoline under extremely mild conditions (0.6 mol% Pd, 0.1 MPa H2 and 50 °C). The kinetic experiments further reveal that such hydrogenation is subject to a pseudo-first order reaction and the apparent activation energy is as low as 41.1 kJ/mol, demonstrating excellent hydrogenation reaction rate. Moreover, the catalytic activity and selectivity are well maintained even after being reused for fifth reaction cycles.
- Zhang, Fengwei,Ma, Chunlan,Chen, Shuai,Zhang, Jianfei,Li, Zhihong,Zhang, Xian-Ming
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p. 145 - 153
(2018/04/27)
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- High efficient iron-catalyzed transfer hydrogenation of quinolines with Hantzsch ester as hydrogen source under mild conditions
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A highly efficient transfer hydrogenation of quinolines with Hantzsch ester as hydrogen source in the presence of 1 mol% Fe(OTf)2 under mild conditions has been developed. A series of substituted 1,2,3,4-tetrahydroquinoline derivatives were afforded in excellent yields with good functional group tolerance.
- He, Renke,Cui, Peng,Pi, Danwei,Sun, Yan,Zhou, Haifeng
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supporting information
p. 3571 - 3573
(2017/10/05)
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- Method for reducing benzo aroma nitrogen-heterocyclic compound
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The invention discloses a method for reducing benzo aroma nitrogen-heterocycle. According to the method, the benzo aroma nitrogen-heterocycle is taken as a raw material, dual-boric acid is taken as a hydrogen source, lewis acid is taken as a catalyst, acetonitrile is taken as a solvent and the benzo aroma nitrogen-heterocyclic compound is acquired under suitable temperature and at suitable time. The method for reducing the benzo aroma nitrogen-heterocyclic compound, provided by the invention, has the advantages of mild condition, low cost, high yield, simplicity in post-processing and suitability for industrial production. The process route is as follows.
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Paragraph 0083; 0084; 0085; 0086
(2017/07/20)
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- A General and Highly Selective Cobalt-Catalyzed Hydrogenation of N-Heteroarenes under Mild Reaction Conditions
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Herein, a general and efficient method for the homogeneous cobalt-catalyzed hydrogenation of N-heterocycles, under mild reaction conditions, is reported. Key to success is the use of the tetradentate ligand tris(2-(diphenylphosphino)phenyl)phosphine). This non-noble metal catalyst system allows the selective hydrogenation of heteroarenes in the presence of a broad range of other sensitive reducible groups.
- Adam, Rosa,Cabrero-Antonino, Jose R.,Spannenberg, Anke,Junge, Kathrin,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 3216 - 3220
(2017/03/17)
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- The photochemical alkylation and reduction of heteroarenes
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The functionalization of heteroarenes has been integral to the structural diversification of medicinally active molecules such as quinolines, pyridines, and phenanthridines. Electron-deficient heteroarenes are electronically compatible to react with relatively nucleophilic free radicals such as hydroxyalkyl. However, the radical functionalization of such heteroarenes has been marked by the use of transition-metal catalyzed processes that require initiators and stoichiometric oxidants. Herein, we describe the photochemical alkylation of quinolines, pyridines and phenanthridines, where through direct excitation of the protonated heterocycle, alcohols and ethers, such as methanol and THF, can serve as alkylating agents. We also report the discovery of a photochemical reduction of these heteroarenes using only iPrOH and HCl. Mechanistic studies to elucidate the underlying mechanism of these transformations, and preliminary results on catalytic methylations are also reported.
- McCallum,Pitre,Morin,Scaiano,Barriault
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p. 7412 - 7418
(2017/10/31)
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- “Naked” Iridium(IV) Oxide Nanoparticles as Expedient and Robust Catalysts for Hydrogenation of Nitrogen Heterocycles: Remarkable Vicinal Substitution Effect and Recyclability
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Iridium(IV) oxide nanoparticles were facilely prepared from iridium trichloride hydrate and sodium hydroxide by a ball-milling reaction at room temperature. The “naked” iridium nanocatalyst showed high stability and activity for the hydrogenation of a series of nitrogen heterocycles, for the first time, under a hydrogen balloon at room temperature with a selectivity of higher than 99%. Besides, an unprecedented substitution-dependent effect was discovered, where substrates with vicinal substituents on 2-, 3-, or 8-positions exhibited distinctly higher reaction rates than unsubstituted or remote substituted ones. Extraordinary recyclability was discovered in the hydrogenation of 2-methylquinoline for 30 runs without loss of activity. (Figure presented.).
- Ji, Yi-Gang,Wei, Kai,Liu, Teng,Wu, Lei,Zhang, Wei-Hua
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supporting information
p. 933 - 940
(2017/03/27)
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- Unique nanocages of 12CaO·7Al2O3 boost heterolytic hydrogen activation and selective hydrogenation of heteroarenes over ruthenium catalyst
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The chemoselective hydrogenation of heteroarenes is one of the most important synthetic reactions for the production of key intermediates in agrochemicals, pharmaceuticals and various fine chemicals. The development of new heterogeneous catalysts for the environmentally benign synthesis of heterocycle hydrogenated products is a fundamental objective for chemists. Here, we report that 12CaO·7Al2O3 with a unique sub-nanocage structure loaded with Ru nanoparticles exhibits higher activity, chemoselectivity and sustainability for the hydrogenation of heteroarenes in a solvent-free system than traditional oxide-supported metal catalysts. Conversion of >99% and a selectivity close to 99% were achieved for the hydrogenation of quinoline under mild conditions. This catalyst was also successfully applied to the hydrogenation of a variety of N- and O-heteroarenes with high yields. The superior catalytic performance can be attributed to a cooperative effect between the hydrogen-storage ability and large amount of strong basic sites on the surface of the support, which promotes heterolytic H2 cleavage and prevents poisoning of the metal surface caused by the adsorption of heteroarenes.
- Ye, Tian-Nan,Li, Jiang,Kitano, Masaaki,Hosono, Hideo
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p. 749 - 756
(2017/05/22)
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- Accelerated catalytic activity of Pd NPs supported on amine-rich silica hollow nanospheres for quinoline hydrogenation
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Tuning the catalytic performance of metal nanoparticles (NPs) is very important in nanocatalysis. Herein, we report that amine-rich mesoporous silica hollow nanospheres (HS-NH2) synthesized by one-pot condensation could efficiently stabilize ultra-small Pd NPs and also increase the surface electron density of Pd NPs due to the coordinating and electron-donating effects of the amine group. Pd NPs supported on HS-NH2 afford TOF as high as 5052 h-1 in quinoline hydrogenation reaction and are much more active than Pd/C with a TOF of 960 h-1 as well as most reported solid catalysts. The intrinsic activity of Pd NPs increases as the particle size of Pd decreases, revealing that quinoline hydrogenation is a structure-sensitive reaction. The results of TEM, XPS, CO adsorption and CO stripping voltammetry indicate that the high activity of Pd NPs supported on HS-NH2 is mainly attributed to their ultra-small particle size and high surface electron density. Our primary results demonstrate that the organo-modified silica nanospheres are promising solid supports for modifying the electronic properties of metal NPs supported and consequently tailoring their catalytic functions.
- Guo, Miao,Li, Can,Yang, Qihua
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p. 2221 - 2227
(2017/07/22)
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- Modular metal-carbon stabilized palladium nanoparticles for the catalytic hydrogenation of N-heterocycles
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We report here the first modular metal-carbon stabilized palladium nanoparticles based on binaphthyl scaffolds, which can be prepared from palladium salts and substituted binaphthyl diazonium salts in homogeneous system through direct reduction using sodium borohydride. The resulting palladium nanoparticles subjected to the electron density of modular moieties are found to be novel and efficient catalysts for the catalytic hydrogenation of N-heterocycles, affording the corresponding adducts in good to excellent yields under mild conditions.
- Zhang, Yu,Mao, Mao,Ji, Yi-Gang,Zhu, Jie,Wu, Lei
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p. 329 - 332
(2016/01/12)
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- Metal-Free Hydrogen Atom Transfer from Water: Expeditious Hydrogenation of N-Heterocycles Mediated by Diboronic Acid
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A hydrogenation of N-heterocycles mediated by diboronic acid with water as the hydrogen atom source is reported. A variety of N-heterocycles can be hydrogenated with medium to excellent yields within 10 min. Complete deuterium incorporation from stoichiometric D2O onto substrates further exemplifies the H/D atom sources. Mechanism studies reveal that the reduction proceeds with initial 1,2-addition, in which diboronic acid synergistically activates substrates and water via a six-membered ring transition state.
- Xia, Yun-Tao,Sun, Xiao-Tao,Zhang, Ling,Luo, Kai,Wu, Lei
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p. 17151 - 17155
(2016/11/23)
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- Diboron-assisted palladium-catalyzed transfer hydrogenation of N-heteroaromatics with water as hydrogen donor and solvent
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A Pd-catalyzed transfer hydrogenation of various N-heteroaromatic compounds with B2pin2 as a mediator and environmentally benign water as both solvent and hydrogen donor has been disclosed. This reaction proceeded under ambient temperature with a broad range of N-heteroaromatic compounds among which imidazo[1,2-a]pyridine derivatives were for the first time selectively reduced to 5,6,7,8-tetrahydroimidazo[1,2-a]pyridines, which are the core structural motifs of an inhibitor of human O-GlcNAcase. Mechanistic studies suggested that the new protons in products are from water and Pd-H might be the key intermediate with B2pin2 as the H2O activator.
- Xuan, Qingqing,Song, Qiuling
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supporting information
p. 4250 - 4253
(2016/09/09)
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- A Rhodium Nanoparticle-Lewis Acidic Ionic Liquid Catalyst for the Chemoselective Reduction of Heteroarenes
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We describe a catalytic system composed of rhodium nanoparticles immobilized in a Lewis acidic ionic liquid. The combined system catalyzes the hydrogenation of quinolines, pyridines, benzofurans, and furan to access the corresponding heterocycles, important molecules present in fine chemicals, agrochemicals, and pharmaceuticals. The catalyst is highly selective, acting only on the heteroaromatic ring, and not interfering with other reducible functional groups.
- Karakulina, Alena,Gopakumar, Aswin,Ak?ok, Ismail,Roulier, Bastien L.,LaGrange, Thomas,Katsyuba, Sergey A.,Das, Shoubhik,Dyson, Paul J.
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supporting information
p. 292 - 296
(2016/01/25)
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- Efficient Hydrogenation of Nitrogen Heterocycles Catalyzed by Carbon-Metal Covalent Bonds-Stabilized Palladium Nanoparticles: Synergistic Effects of Particle Size and Water
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We reveal here the first hydrogenation of nitrogen heterocycles catalyzed by carbon–metal covalent bonds-stabilized palladium nanoparticles in water under mild conditions. Using a one-phase reduction method, smaller metal–carbon covalent bond-stabilized Pd nanoparticles were prepared with a size distribution of 2.5±0.5 nm, which showed extraordinary synergistic effects with water in the catalytic hydrogenation of nitrogen heterocycles. Water was supposed to accelerate substrate absorption and synergistic activation of molecular hydrogen on the Pd nanoparticles surface. The nanosized Pd catalyst could be easily recovered and reused for 5 runs. (Figure presented.).
- Zhang, Yu,Zhu, Jie,Xia, Yun-Tao,Sun, Xiao-Tao,Wu, Lei
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supporting information
p. 3039 - 3045
(2016/10/09)
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- 4,5,6,7-TETRAHYDRO-1 H-PYRAZOLO[4,3-C]PYRIDIN-3-AMINE COMPOUNDS AS CBP AND/OR EP300 INHIBITORS
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The present invention relates to compounds of formula (I) or formula (II): and to salts thereof, wherein R1-R4 of formula (I) and R1-R3 of formula (II) have any of the values defined herein, and compositions and uses thereof. The compounds are useful as inhibitors of CBP and/or EP300. Also included are pharmaceutical compositions comprising a compound of formula (I) of formula (II) or a pharmaceutically acceptable salt thereof, and methods of using such compounds and salts in the treatment of various CBP and/or EP300-mediated disorders.
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Page/Page column 245
(2016/06/14)
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- Selective Catalytic Hydrogenation of Heteroarenes with N-Graphene-Modified Cobalt Nanoparticles (Co3O4-Co/NGratα-Al2O3)
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Cobalt oxide/cobalt-based nanoparticles featuring a core-shell structure and nitrogen-doped graphene layers on alumina are obtained by pyrolysis of Co(OAc)2/phenanthroline. The resulting core-shell material (Co3O4-Co/NGratα-Al2O3) was successfully applied in the catalytic hydrogenation of a variety of N-heteroarenes including quinolines, acridines, benzo[h], and 1,5-naphthyridine as well as unprotected indoles. The peculiar structure of the novel heterogeneous catalyst enables activation of molecular hydrogen at comparably low temperature. Both high activity and selectivity were achieved in these hydrogenation processes, to give important building blocks for bioactive compounds as well as the pharmaceutical industry.
- Chen, Feng,Surkus, Annette-Enrica,He, Lin,Pohl, Marga-Martina,Radnik, J?rg,Topf, Christoph,Junge, Kathrin,Beller, Matthias
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supporting information
p. 11718 - 11724
(2015/09/28)
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- Versatile (Pentamethylcyclopentadienyl)rhodium-2,2′-Bipyridine (Cp?Rh-bpy) Catalyst for Transfer Hydrogenation of N-Heterocycles in Water
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An investigation employing the catalytic system consisting of (pentamethylcyclopentadienyl)rhodium dichloride dimer [Cp?RhCl2]2 and 2,2′-bipyridine (bpy) for transfer hydrogenation of a variety of quinoxalines, quinoxalinones, quinolines and indoles under aqueous conditions with formate as the hydrogen source is reported. This approach provides various tetrahydroquinoxalines, dihydroquinoxalinones, tetrahydroquinolines and indolines in good to excellent yields. The activity of the catalyst towards quinoxalines and quinoxalinones is excellent, with a substrate to catalyst ratio (S/C) of 10000 being feasible. The choice of ligand is critical to the catalysis, and the aqueous phase reduction is shown to be highly pH-dependent, with acidic pH values needed for optimal reduction. The catalyst is easy to access, and the reaction is operationally simple without requiring an inert atmosphere.
- Zhang, Lingjuan,Qiu, Ruiying,Xue, Xiao,Pan, Yixiao,Xu, Conghui,Li, Huanrong,Xu, Lijin
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supporting information
p. 3529 - 3537
(2016/01/25)
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- A simple iridicycle catalyst for efficient transfer hydrogenation of n-heterocycles in water
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A cyclometalated iridium complex is shown to catalyse the transfer hydrogenation of various nitrogen heterocycles, including but not limited to quinolines, isoquinolines, indoles and pyridinium salts, in an aqueous solution of HCO2H/HCO2Na under mild conditions. The catalyst shows excellent functional-group compatibility and high turnover number (up to 7500), with catalyst loadings as low as 0.01 mol % being feasible. Mechanistic investigation of the quinoline reduction suggests that the transfer hydrogenation proceeds via both 1,2- and 1,4-addition pathways, with the catalytic turnover being limited by the step of hydride transfer. An easily accessible iridicycle catalyst effects the transfer hydrogenation of a wide variety of N-heterocycles in water, including quinolines, isoquinolines, indoles, quinoxalines, and pyridines. The catalyst shows excellent functional-group compatibility and high turnover number (up to 7500), even with low catalyst loadings.
- Talwar, Dinesh,Li, Ho Yin,Durham, Emma,Xiao, Jianliang
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supporting information
p. 5370 - 5379
(2015/03/30)
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- Heterogeneous gold-catalyzed selective reductive transformation of quinolines with formic acid
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Single phase rutile titania supported gold nanoparticles (Au/TiO2-R) are found to be efficient and versatile catalysts for chemo- and regioselective transfer hydrogenation of quinoline derivatives to 1,2,3,4-tetrahydroquinolines (THQs) using formic acid (FA) as a safe and convenient hydrogen source under mild conditions. The activity and chemoselectivity of the Au/TiO2-R catalyst towards THQs is excellent, with a substrate to catalyst ratio (S/C) of 1000 being feasible. Furthermore, a straightforward and selective route to N-formyltetrahydroquinolines (FTHQ) directly from quinoline compounds and FA by one-pot, gold-catalyzed reductive N-formylation protocol is also established.
- Tao, Lei,Zhang, Qi,Li, Shu-Shuang,Liu, Xiang,Liu, Yong-Mei,Cao, Yong
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supporting information
p. 753 - 760
(2015/03/18)
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- Halogen-bonding-induced hydrogen transfer to C=N bond with hantzsch ester
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Several bidentate dihydroimidazolines were prepared and investigated as catalysts for hydrogen transfer reduction of C=N bond with Hantzsch ester. Highly efficient reactions were observed for quinolines and imines with low catalyst loading of 2 mol %. The presence of halogen bonding was elucidated using NMR studies and isothermal calorimeric titrations. Binding constants of the XB donors were also measured using isothermal calorimeric titrations (ITC).
- He, Wei,Ge, Yi-Cen,Tan, Choon-Hong
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supporting information
p. 3244 - 3247
(2014/07/08)
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- Robust cyclometallated Ir(iii) catalysts for the homogeneous hydrogenation of N-heterocycles under mild conditions
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Cyclometallated Cp*Ir(N∧C)Cl complexes derived from N-aryl ketimines are highly active catalysts for the reduction of N-heterocycles under ambient conditions and 1 atm H2 pressure. The reaction tolerates a broad range of other potentially reducible functionalities and does not require the use of specialised equipment, additives or purified solvent.
- Wu, Jianjun,Barnard, Jonathan H.,Zhang, Yi,Talwar, Dinesh,Robertson, Craig M.,Xiao, Jianliang
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supporting information
p. 7052 - 7054
(2013/09/02)
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