- Cu nanoparticles embedded on reticular chitosan-derived N-doped carbon: Application to the catalytic hydrogenation of alkenes, alkynes and N-heteroarenes
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Applying biomass-waste as catalysts and catalytic supports is gaining a tremendous interest owing to its expected outcomes in terms of cost effectiveness and sustainability. In this context, we herein disclose a straightforward encapsulation of nanosized copper on hierarchically porous, biomass-derived nitrogen-containing carbon framework. Our approach uses chitosan - derived from the marine shell-fish wastes - as a cheap, sustainable carbon and nitrogen source, melamine as nitrogen provider and ethylenediaminetetraacetic acid as a cross-linker to induce the reticular network, much suitable for restricting the growth of the metal seeds. The resulting copper grown on nitrogen-doped carbon, bearing relatively large surface area (106 m2·g?1) and a large group of well-dispersed Cu nanoparticles (average of 2 nm) even with high Cu loading (41 wt%), exhibits catalytic activity for the hydrogenation of unsaturated double and triple carbon-carbon bonds and heteroaryles. This sustainable design of catalyst, using affordable copper and cheap biowaste, could discard palladium and other expensive elements loaded on tedious synthetic supports from the library of heterogeneous solids intended for fine chemical synthesis.
- Chen, Shuo,El Kadib, Abdelkrim,Hammi, Nisrine,Michon, Christophe,Royer, Sebastien
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- Engineering the geometric and electronic structure of Ru: Via Ru-TiO2interaction for enhanced selective hydrogenation
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Modulation of the metal-support interaction plays a key role in many important chemical reactions. Here, by adjusting the reduction method of the catalyst and introducing oxygen vacancies in TiO2 to regulate the interaction between Ru and TiO2, four supported Ru nanocatalysts with different encapsulation degrees and electronic structures were obtained. Ru nanoparticles (NPs) partially encapsulated by TiO2 can achieve the selective hydrogenation of 6-chloroquinoline even at room temperature, with a TOF of 12 h-1. Catalytic characterization and DFT calculations indicated that partially encapsulated Ru NPs not only provided active sites for H2 dissociation, but also reduced the probability of Ru NPs being poisoned. Meanwhile, the oxygen vacancies on the surface of TiO2 can adsorb 6-chloroquinoline molecules and provide additional active sites for hydrogenation via hydrogen spillover. Moreover, the enhanced electron transfer from oxygen-deficient TiO2 to Ru made Ru electron-rich, which repelled C-Cl bonds and effectively prevented the production of dechlorination products. This journal is
- Huang, Songtao,Li, Aiyuan,Shao, Fangjun,Wang, Jianguo,Wei, Zhongzhe,Yao, Zihao,Zhao, Zijiang,Zhou, Qiang
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p. 1005 - 1016
(2022/02/17)
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- Identification and synthesis of DDI-6, a quinolinol analog capable of activating both caenorhabditis elegans and mouse spermatozoa
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Sperm activation is an essential process by which the male gametes become capable of fertilization. Because the process in Caenorhabditis elegans is readily reproducible in vitro, this organism serves as an excellent model to investigate it. C. elegans sperm activation in vivo occurs during spermiogenesis. Membranous organelles (MOs) contained within spermatids fuse with the plasma membrane, resulting in extracellular release of their contents and relocation of some proteins indispensable for fertilization from the MO membrane onto the sperm surface. Intriguingly, these cytological alternations are exhibited similarly in mouse spermatozoa during the acrosome reaction, which also represents a form of sperm activation, prompting us to hypothesize that C. elegans and mice share a common mechanism for sperm activation. To explore this, we first screened a chemical library to identify compounds that activate C. elegans spermatozoa. Because a quinolinol analog named DDI-6 seemed to be a candidate sperm activator, we synthesized it to use for further analyses. This involved direct dechlorination and hydrogenolysis of commercially available 5-chloro-8-quinolinol, both of which are key steps to yield 1,2,3,4-tetrahydro-8-quinolinol, and we subsequently introduced the sulfonamide group to the compound. When C. elegans spermatids were stimulated with solvent alone or the newly synthesized DDI-6, approx. 3% and approx. 28% of spermatids became MO-fused spermatozoa, respectively. Moreover, DDI-6 triggered the acrosome reaction in approx. 20% of mouse spermatozoa, while approx. 12% became acrosome-reacted after mock stimulation. Thus, DDI-6 serves as a moderately effective activator for both C. elegans and mouse spermatozoa.
- Karuo, Yukiko,Shiraki, Riona,Yoshida, Ayaka,Tsunokawa, Ryo,Nakahara-Yamada, Mayuko,Tarui, Atsushi,Sato, Kazuyuki,Kawai, Kentaro,Omote, Masaaki,Nishimura, Hitoshi
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p. 557 - 563
(2021/06/06)
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- Geometric and electronic effects on the performance of a bifunctional Ru2P catalyst in the hydrogenation and acceptorless dehydrogenation of N-heteroarenes
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The development of bifunctional catalysts for the efficient hydrogenation and acceptorless dehydrogenation of N-heterocycles is a challenge. In this study, Ru2P/AC effectively promoted reversible transformations between unsaturated and saturated N-heterocycles affording yields of 98% and 99%, respectively. Moreover, a remarkable enhancement in the reusability of Ru2P/AC was observed compared with other Ru-based catalysts. According to density functional theory calculations, the superior performance of Ru2P/AC was ascribed to specific synergistic factors, namely geometric and electronic effects induced by P. P greatly reduced the large Ru-Ru ensembles and finely modified the electronic structures, leading to a low reaction barrier and high desorption ability of the catalyst, further boosting the hydrogenation and acceptorless dehydrogenation processes.
- Shao, Fangjun,Yao, Zihao,Gao, Yijing,Zhou, Qiang,Bao, Zhikang,Zhuang, Guilin,Zhong, Xing,Wu, Chuan,Wei, Zhongzhe,Wang, Jianguo
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p. 1185 - 1194
(2021/02/16)
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- Encapsulating Cobalt into N-Doping Hollow Frameworks for Efficient Cascade Catalysis
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The development of nonprecious catalysts for hydrogenation of organic molecules is of great importance in heterogeneous catalysis. Herein, we report a series of N-doped hollow carbon frameworks encompassing cobalt nanoparticles (denoted as Co@NHF-900) constructed as a new kind of reusable catalyst for this purpose by pyrolysis of ZIF-8@Co-dopamine under Ar atmospheres. Notably, the framework of ZIF-8 is essential for efficient catalyst by providing a carbon framework to support Co-dopamine. The experimental results reveal that the ZIF-8 renders a large hollow place within the catalysts, allowing the enrichment of the substrate and windows of the hollow structure and the ease of mass transfer of products during the reaction. All of the virtues made Co@NHF-900 a good candidate for hydrogenation of quinolines with high activity (TOF value of 119 h-1, which is several times than that of akin catalysts) and chemoselectivity.
- Yun, Ruirui,Zhang, Beibei,Qiu, Chuang,Ma, Ziwei,Zhan, Feiyang,Sheng, Tian,Zheng, Baishu
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supporting information
p. 9757 - 9761
(2021/06/30)
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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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- Cu Nanoclusters Anchored on the Metal-Organic Framework for the Hydrolysis of Ammonia Borane and the Reduction of Quinolines
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Free-access active sites created and the interaction regulated between them and substrates during the heterogeneous catalysis process are crucial, which remain a great challenge. In this work, in suit reduced to afford naked Cu nanoparticles (NPs) have been anchored on the metal-organic framework (MOF), NH2-MOF, to form Cu-NH2-MOF. The strategy can precisely control the Cu NP formation with small size and uniform distribution. The Cu NP properties and MOF advantages have been integrated to create a great catalyst with multiple functions and have resulted in improving the recyclability and superb catalytic activity for the one-pot reduction of heterocycle reactions under mild conditions. The experimental and theoretical calculation results show that the superior performance should be attributed to the framework of NH2-MOF that provides large caves for substrate enrichment and the stabilization of Cu sites by the -NH2 group.
- Yun, Ruirui,Zhang, Beibei,Zhan, Feiyang,Du, Liting,Wang, Zhaoxu,Zheng, Baishu
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supporting information
p. 12906 - 12911
(2021/08/30)
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- Palladium supported on magnesium hydroxyl fluoride: An effective acid catalyst for the hydrogenation of imines and N-heterocycles
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Palladium catalysts supported on acidic fluorinated magnesium hydroxide Pd/MgF2-x(OH)x were prepared through precipitation or impregnation methods. Applications to the hydrogenation of various aldimines and ketimines resulted in good catalytic activities at mild temperatures using one atmosphere of hydrogen. Quinolines, pyridines and other N-heterocycles were successfully hydrogenated at higher temperature and hydrogen pressure using low palladium loadings and without the use of any acid additive. Such reactivity trend confirmed the positive effect of the Br?nsted and Lewis acid sites from the fluorinated magnesium hydroxide support resulting in the effective pre-activation of N-heterocycle substrates and therefore in the good catalytic activity of the palladium nanoparticles during the hydrogenations. As demonstrated in the hydrogenation of imines, the catalyst was recycled up to 10 times without either loss of activity or palladium leaching. This journal is
- Agbossou-Niedercorn, Francine,Corre, Yann,Dongare, Mohan K.,Kemnitz, Erhard,Kokane, Reshma,Michon, Christophe,Umbarkar, Shubhangi B.
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supporting information
p. 19572 - 19583
(2021/11/04)
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- A proton-responsive annulated mesoionic carbene (MIC) scaffold on IR complex for proton/hydride shuttle: An experimental and computational investigation on reductive amination of aldehyde
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A Cp*Ir(III) complex (1) bearing a proton-responsive hydroxy unit on an annulated imidazo[1,2-a][1,8]naphthyridine based mesoionic carbene scaffold was synthesized by two different synthetic routes. The molecular structure of 1 revealed an anionic lactam form of the ligand. The acid?base equilibrium between the lactam-lactim tautomers on the ligand scaffold was examined by 1H NMR and UV?vis spectra. The pKa of the appendage ?OH group in the lactim form of 1 was estimated to assess the proton transfer property of the catalyst. The catalytic efficacy of 1 for reductive amination of aldehyde was evaluated by utilizing three different hydrogen sources: molecular H2iPrOH/KOtBu combination, and HCOOH/Et3N (5:2) azeotropic mixture. The HCOOH/Et3N (5:2) azeotropic mixture rotocol was found to be the best amon the three different h dro enation methods. Catalyst 1 hydrogenates imines chemoselectively over carbonyls under the reaction conditions. A range of aldehydes was reductively aminated to the corresponding secondary amines using the HCOOH/Et3N (5:2) azeotropic mixture. Further, catalyst 1 showed high efficiency for the reduction of a wide variety of N-heterocyclic imine derivatives. The lactam-lactim tautomerization of the ligand system is proposed for direct hydrogenation, whereas only the lactam form operates in the strongly basic medium (iPrOH/KOtBu). Under HCOOH/Et3N (5:2) conditions, the lactam scaffold is not protonated; rather, an outer-sphere hydride transfer from formate to the Ir is proposed, which is supported by 1H NMR and DFT calculations. Finally, ligand-promoted hydride transfer from metal-hydride to the protonated imine affords the corresponding amine. A close agreement between the experimentally estimated and computed thermodynamic/kinetic parameters gives credence to the metal-ligand cooperative mechanism for the imine hydrogenation reaction using the HCOOH/Et3N (5:2) azeotropic mixture.
- Bera, Jitendra K.,Daw, Prosenjit,Din Reshi, Noor U.,Ehmann, Kira R.,H?lscher, Markus,Leitner, Walter,Pandey, Pragati
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p. 3849 - 3863
(2020/11/23)
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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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- Au Nanoparticles Confined in SBA-15 as a Highly Efficient and Stable Catalyst for Hydrogenation of Quinoline to 1,2,3,4-Tetrahydroquinoline
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Abstract: Au nanoparticles confined within the mesopores of the modified SBA-15 were obtained through adsorption-reduction method and firstly employed as chemoselective catalyst for quinoline hydrogenation. The effects of Au loadings, calcination temperature as well as structure of support on catalytic performances of Au catalysts were explored. The as-obtained 1.2percentAu@SBA-15-500 catalyst exhibited high activity, excellent selectivity towards 1,2,3,4-tetrahydroquinoline and extraordinary sintering-resistant property as high as 800?°C, which is sharp contrast to the 1.3percentAu/SiO2-500 catalyst. It also showed good recyclability and versatility for quinoline derivatives. The observed properties were assigned to small-sized Au nanoparticles and mesopores of SBA-15. Our work provides a facile and promising approach to construct metal nanocatalysts with high catalytic performance by the use of mesoporous materials. Graphic Abstract: [Figure not available: see fulltext.].
- Zhao, Jianbo,Yuan, Haifeng,Qin, Xiaomei,Tian, Kuan,Liu, Yingfan,Wei, Chengzhen,Zhang, Zhiqiang,Zhou, Liming,Fang, Shaoming
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p. 2841 - 2849
(2020/03/30)
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- NHC-Palladium(II) Mononuclear and Binuclear Complexes Containing Phenylene-Bridged Bis(thione) Ligands: Synthesis, Characterization, and Catalytic Activities
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A series of mono- and binuclear Pd(II) complexes with N-heterocyclic carbene (NHC) and phenylene-bridged bis(thione) (SCS) ligands were prepared and characterized by 1H and 13C NMR spectroscopy, IR, and mass spectrometry. The molecular structures of 1b, 2a, and 3b have been determined by the single-crystal X-ray diffraction method. The catalytic activities of the synthesized palladium complexes in the regioselective reduction of quinolines to the corresponding 1,2,3,4-tetrahydroquinolines were thoroughly investigated with ammonia-borane under mild reaction conditions. It is observed that the activities of the binuclear Pd(NHC) complexes were higher than those of the corresponding mononuclear complexes under the same conditions.
- Jia, Wei-Guo,Gao, Li-Li,Wang, Zhi-Bao,Wang, Jing-Jing,Sheng, En-Hong,Han, Ying-Feng
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p. 1790 - 1798
(2020/05/14)
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- Phyllosilicate-derived Nickel-cobalt Bimetallic Nanoparticles for the Catalytic Hydrogenation of Imines, Oximes and N-heteroarenes
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The development of cost-effective, noble metal-free catalytic systems for the hydrogenation of unsaturated aliphatic, aromatic, and heterocyclic compounds is fundamental for future valorization of general feedstock. With this aim, we report here the preparation of highly dispersed bimetallic Ni/Co nanoparticles (NPs), by a one-pot deposition-precipitation of Ni and Co phases onto mesoporous SBA-15 silica. By adjusting the chemical composition in the starting mixture, three supported catalysts with different Ni to Co weight ratios were obtained, which were further subjected to treatments under reducing conditions at high temperatures. Characterization of the resulting solids evidenced a homogenous distribution of Ni and Co elements forming the NPs, the best results being obtained for Ni/Co-2 : 2 samples, for which 50 wt.percent Ni–50 wt.percent Co NPs are found located on the surface of the residual phyllosilicate. Ni/Co-2 : 2, presenting the best performances for the hydrogenation of 2-methyl-quinoline, was further evaluated in the catalytic hydrogenation of selected imines, oximes and N-heteroarenes. Due to the high dispersion of bimetallic Ni?Co NPs, excellent properties (activity and selectivity) in the conversion of the selected substrates are reported.
- Ciotonea, Carmen,Hammi, Nisrine,Dhainaut, Jérémy,Marinova, Maya,Ungureanu, Adrian,El Kadib, Abdelkrim,Michon, Christophe,Royer, Sébastien
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p. 4652 - 4663
(2020/08/19)
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- Dual-Active-Sites Design of Co@C Catalysts for Ultrahigh Selective Hydrogenation of N-Heteroarenes
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The dual-active-sites Co@C catalyst provides a general powerful strategy to break the limitation of scaling relation on traditional metal surfaces and thus affords unprecedentedly selective hydrogenation of various N-heteroarenes as well as high activity and stability. A porous carbon shell not only allows H2 diffusion to Co sites for activation but also blocks accessibility of N-heteroarenes, and the hydrogenation of N-heteroarenes is achieved on carbon by the spilled hydrogen from Co sites. In addition, the presence of surface/subsurface carbon at the Co sites shows high anti-sulfur poisoning and anti-oxidant capability. Ideal heterogeneous metal hydrogenation catalysts are featured by simultaneously high activity, selectivity, and stability. Herein, we report a general yet powerful strategy to design and fabricate dual-active-sites Co@C core-shell nanoparticle for boosting selective hydrogenation of various N-heteroarenes. It can break the limitation of scaling relation on traditional metal surfaces, and thus afford unprecedentedly high selectivity, activity, and stability. Combining kinetics analysis and DFT calculations with multiple techniques directly unveil that the critical porous carbon shell with a pore size of 0.53 nm not only allows H2 diffusion to Co sites for activation and blocks accessibility of N-heteroarenes but also catalyzes hydrogenation of N-heteroarenes via hydrogen spillover from Co sites. In addition, the presence of surface/subsurface carbon at the Co sites shows high anti-sulfur poisoning and anti-oxidant capability. This work is valuable for guiding the design and manipulation of cost-effective and robust hydrogenation catalysts. Our research can provide an environmentally friendly approach to afford unprecedentedly selective N-heteroarenes hydrogenation, which will greatly reduce the resource and energy consumption and decrease the amount of waste discharge and water pollution. Therefore, these results could help in achieving the “Clean water and sanitation” goal in the 10 UN Sustainable Development Goals. Meanwhile, the products of N-heteroarenes hydrogenation are the core structural motifs in both fine and bulk chemicals, which will make our life more beautiful. Thus, our research also benefits the “Good health and well-being” goal.
- Zhang, Sai,Gan, Jie,Xia, Zhaoming,Chen, Xiao,Zou, Yong,Duan, Xuezhi,Qu, Yongquan
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supporting information
p. 2994 - 3006
(2020/09/04)
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- Water-assisted one-pot synthesis of N-doped carbon supported Ru catalysts for heterogeneous catalysis
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For the first time, a simple yet efficient water-assisted one-pot pyrolysis (WAOP) strategy was developed toin situliberate the inaccessible Ru active sites confined inside N-doped carbon. The liberated Ru/CN catalysts exhibit a 9-fold improvement in catalytic activity for quinoline hydrogenation compared with catalysts obtained from the water-free pyrolysis process, and high tolerance for selective hydrogenation of various quinolines substituted with different functional groups. We anticipate that WAOP addresses a key issue that currently plagues carbon-based catalyst synthesis and should lead to improvements in fields as diverse as chemical production and environmental protection.
- Cao, Yueling,Chen, Kai-Jie,Liu, Kangkai,Zhang, Hepeng
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supporting information
p. 11311 - 11314
(2020/10/06)
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- Iridium-Catalyzed Hydrogenation and Dehydrogenation of N-Heterocycles in Water under Mild Conditions
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An efficient catalytic method is presented for the hydrogenation of N-heterocycles. The iridium-based catalyst operates under mild conditions in water without any co-catalyst or stoichiometric additives. The catalyst also promotes the reverse reaction of dehydrogenation of N-heterocycles, hence displaying appropriate characteristics for a future hydrogen economy based on liquid organic hydrogen carriers (LOHCs).
- Wang, Shengdong,Huang, Haiyun,Bruneau, Christian,Fischmeister, Cédric
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p. 2350 - 2354
(2019/05/21)
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- Monofunctional PtII Complexes Based on 8-Aminoquinoline: Synthesis and Pharmacological Characterization
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Among the heterocyclic compounds, 8-aminoquinoline and its derivatives have become important candidates for the preparation of new antiproliferative metallo-drugs. Here, we reported the synthesis and cytotoxicity evaluation of a series of platinum complexes using 8-aminoquinoline and its chiral 5,6,7,8-tetrahydro-derivatives as chelating ligands. In the proposed complexes, a differently and opportunely alkylated imidazole was used to prepare the corresponding monofunctional platinum complexes. The preliminary cytotoxicity evaluation was carried out on the highly aggressive MDA-MB-231, invasive and poorly differentiated triple-negative breast cancer (TNBC) cell line, furnishing a significant IC50 10.9 ± 1.3 μM for Pt-IV. This series of complexes revealed an induction of p53, interfering with the progression of the G0/G1 phase of the cell cycle.
- Facchetti, Giorgio,Ferri, Nicola,Lupo, Maria Giovanna,Giorgio, Lucchini,Rimoldi, Isabella
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p. 3389 - 3395
(2019/08/01)
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- Liberating N-CNTs Confined Highly Dispersed Co?Nx Sites for Selective Hydrogenation of Quinolines
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Selective hydrogenation of quinoline and its derivatives is an important means to produce corresponding 1,2,3,4-tetrahydroquinolines for a wide spectrum of applications. A facile and efficient “laser irradiation in liquid” technique to liberate the inaccessible highly dispersed Co?Nx active sites confined inside N-doped carbon nanotubes is demonstrated. The liberated Co?Nx sites possess generic catalytic activities toward selective hydrogenation of quinoline and its hydroxyl, methyl, and halogen substituted derivatives into corresponding 1,2,3,4-tetrahydroquinolines with almost 100% conversion efficiency and selectivity. This laser irradiation treatment approach should be widely applicable to unlock the catalytic powers of inaccessible catalytic active sites confined by other materials.
- Gong, Wanbing,Yuan, Qinglin,Chen, Chun,Lv, Yang,Lin, Yue,Liang, Changhao,Wang, Guozhong,Zhang, Haimin,Zhao, Huijun
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- Ruthenium(II)-Catalyzed Regioselective C-8 Hydroxylation of 1,2,3,4-Tetrahydroquinolines
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Ru(II)-catalyzed chelation-assisted highly regioselective C8-hydroxylation of 1,2,3,4-tretrahydroquinolines has been developed. Various 1,2,3,4-tetrahydroquinolines underwent smooth C8-H hydroxylation with cheap and safe K2S2O8 as the oxidant and oxygen source to furnish the corresponding products in good to excellent yields with high tolerance of the functional groups. The choice of a readily installable and removable N-pyrimidyl directing group is the key to catalysis. Mechanistic studies suggest the involvement of a six-membered ruthenacycle intermediate in the catalytic cycle. The method can also be extended to the direct hydroxylation of other (hetero)arene C-H bonds.
- Chen, Changjun,Pan, Yixiao,Zhao, Haoqiang,Xu, Xin,Luo, Zhenli,Cao, Lei,Xi, Siqi,Li, Huanrong,Xu, Lijin
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p. 6799 - 6803
(2018/11/21)
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- Regioselective and Chemoselective Reduction of Naphthols Using Hydrosilane in Methanol: Synthesis of the 5,6,7,8-Tetrahydronaphthol Core
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A regioselective and chemoselective method for catalytic synthesis of biologically interesting 5,6,7,8-tetrahydronaphthols by reduction of naphthols was described. The side aromatic hydrocarbons in naphthols were site-selectively reduced, using hydrosilanes in methanol, allowing for retaining functional phenol scaffolds intact. It presents a rare example of using low-cost and air-stable hydrosilane for catalytic reduction of unactivated aromatic hydrocarbons under mild conditions. This reaction is scalable and proceeds in high selectivity without the formation of 1,2,3,4-tetrahydronaphthol byproducts with toleration of sensitive functionalities such as bromide, chloride, fluoride, ketone, ester, and amide.
- He, Yuan,Tang, Jinghua,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 4159 - 4163
(2018/07/29)
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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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- 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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- Chemoselective reduction of heteroarenes with a reduced graphene oxide supported rhodium nanoparticle catalyst
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Rhodium nanoparticles immobilized on reduced graphene oxide were obtained from the microwave-induced thermal decomposition of Rh6(CO)16 in the ionic liquid [bmim][BF4] (bmim = 1-butyl-3-methylimidazolium cation) in the absence of additional stabilizing agents. The resulting rhodium nanoparticles are 99%, without interfering with other reducible groups, and with high conversions. Related catalysts prepared using conventional thermal heating were prepared for comparison purposes and were found to be considerably less active.
- Karakulina, Alena,Gopakumar, Aswin,Fei, Zhaofu,Dyson, Paul J.
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p. 5019 - 5097
(2018/10/17)
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- Boron-Catalyzed Hydrogenative Reduction of Substituted Quinolines to Tetrahydroquinolines with Hydrosilanes
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A metal-free procedure for the hydrogenative reduction of substituted N-heteroaromatics has been developed by using hydrosilanes as reducing agents. The optimized conditions were successfully applied to the reactions of quinolines, quinoxalines, and quinoline N -oxides. They were also effective for the reduction of quinolines bearing amino or hydroxy groups, where H 2 was evolved through dehydrogenative silylation of the amine or hydroxy moieties. Preliminary mechanistic studies revealed that the initial step in the catalytic cycle involves 1,4-addition of the hydrosilane to the quinoline to give a 1,4-dihydroquinoline; this is followed by (transfer) hydrogenation to deliver the tetrahydroquinoline as the final product.
- Gandhamsetty, Narasimhulu,Park, Sehoon,Chang, Sukbok
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supporting information
p. 2396 - 2400
(2017/11/04)
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- Uncoordinated Amine Groups of Metal-Organic Frameworks to Anchor Single Ru Sites as Chemoselective Catalysts toward the Hydrogenation of Quinoline
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Here we report a precise control of isolated single ruthenium site supported on nitrogen-doped porous carbon (Ru SAs/N-C) through a coordination-assisted strategy. This synthesis is based on the utilization of strong coordination between Ru3+ and the free amine groups (-NH2) at the skeleton of a metal-organic framework, which plays a critical role to access the atomically isolated dispersion of Ru sites. Without the assistance of the amino groups, the Ru precursor is prone to aggregation during the pyrolysis process, resulting in the formation of Ru clusters. The atomic dispersion of Ru on N-doped carbon can be verified by the spherical aberration correction electron microscopy and X-ray absorption fine structure measurements. Most importantly, this single Ru sites with single-mind N coordination can serve as a semihomogeneous catalyst to catalyze effectively chemoselective hydrogenation of functionalized quinolones.
- Wang, Xin,Chen, Wenxing,Zhang, Lei,Yao, Tao,Liu, Wei,Lin, Yue,Ju, Huanxin,Dong, Juncai,Zheng, Lirong,Yan, Wensheng,Zheng, Xusheng,Li, Zhijun,Wang, Xiaoqian,Yang, Jian,He, Dongsheng,Wang, Yu,Deng, Zhaoxiang,Wu, Yuen,Li, Yadong
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supporting information
p. 9419 - 9422
(2017/07/24)
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- Organo-Photoredox Catalyzed Oxidative Dehydrogenation of N-Heterocycles
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We report here for the first time the catalytic oxidative dehydrogenation of N-heterocycles by a visible-light organo-photoredox catalyst with low catalyst loading (0.1–1 mol %). The reaction proceeds efficiently under base- and additive-free conditions with ambient air at room temperature. The utility of this benign approach is demonstrated by the synthesis of various pharmaceutically relevant N-heteroarenes such as quinoline, quinoxaline, quinazoline, acridine, and indole.
- Sahoo, Manoj K.,Jaiswal, Garima,Rana, Jagannath,Balaraman, Ekambaram
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supporting information
p. 14167 - 14172
(2017/10/16)
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- Method for preparing 1,2,3,4-tetrahydroquinoline compound
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The invention discloses a method for preparing a 1,2,3,4-tetrahydroquinoline compound. The reaction formula of the synthesis method is shown in the description. In the reaction formula, R represents aromatic ring groups; a catalyst is prepared from polymer microsphere loaded metal nanoparticles; the general formula of the catalyst is Poly(X-co-Y)M. The method is characterized by reacting under the normal temperature and normal pressure; an efficient, simple and safe method is supplied to preparation of the 1,2,3,4-tetrahydroquinoline compound.
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Paragraph 0018; 0019
(2016/10/24)
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- Selective N-cycle hydrogenation of quinolines with sodium borohydride in aqueous media catalyzed by hectorite-supported ruthenium nanoparticles: Dedicated to Professor Heinrich Lang on the occasion of his 60th birthday
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A new catalyst containing metallic ruthenium nanoparticles intercalated in hectorite (nanoRu'@hectorite) was found to catalyze the reduction of quinoline and quinoline derivatives by NaBH4in aqueous solution to give selectively the corresponding 1,2,3,4-tetrahydroquinolines (N-cycle hydrogenation). In most cases the reaction can be done under mild conditions (25–60 °C) without pressure equipment, conversion and selectivity being superior to 99%. In the case of sterically hindered derivatives, the reaction can be done in a pressure vessel under self-generated pressure (up to 9 bar). Isoquinoline and quinoxalines also undergo selective N-cycle hydrogenation, but 2-phenyl-quinoline is hydrogenated to give 2-phenyl-5,6,7,8-tetrahydroquinoline (C-cycle hydrogenation). Isotope labeling experiments combined with semi-empirical calculations of the electrostatic potentials support a heterolytic hydrogenation mechanism involving a hydride from NaBH4and a proton from H2O. The catalyst nanoRu'@hectorite can be recycled and reused.
- Sun, Bing,Carnevale, Diego,Süss-Fink, Georg
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p. 197 - 205
(2016/10/30)
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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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- Cobalt Encapsulated in N-Doped Graphene Layers: An Efficient and Stable Catalyst for Hydrogenation of Quinoline Compounds
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Porous nitrogen-doped graphene layers encapsulating cobalt nanoparticles (NPs) were prepared by the direct pyrolysis process. The resulting hybrids catalyze the hydrogenation of diverse quinoline compounds to access the corresponding tetrahydro derivatives (THQs), important molecules present in fine and bulk chemicals. Near-quantitative yields of the corresponding THQs were obtained under optimized conditions. Notably, various useful substituted quinolines and other biologically important N-heteroarenes are also viable. The enhanced stability of the catalyst is ascribed to the encapsulation structure, which can enormously reduce the extent of leaching of base metals and protect metal NPs from growing larger. The achieved success in the encapsulation of metal NPs within graphene layers opens an avenue for the design of highly active and reusable heterogeneous catalysts for more challenging molecules.
- Wei, Zhongzhe,Chen, Yiqing,Wang, Jing,Su, Diefeng,Tang, Minghui,Mao, Shanjun,Wang, Yong
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p. 5816 - 5822
(2016/09/09)
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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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- 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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- 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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- 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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- 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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- Quenched skeletal Ni as the effective catalyst for selective partial hydrogenation of polycyclic aromatic hydrocarbons
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Quenched skeletal Ni is an active and selective catalyst for selective partial hydrogenation of polycyclic aromatic hydrocarbons (PAHs). The molecular structure of PAHs significantly dominate the hydrogenation process and furthermore, the distribution of hydrogenated products.
- Liu, Chengyun,Rong, Zeming,Sun, Zhuohua,Wang, Yong,Du, Wenqiang,Wang, Yue,Lu, Lianhai
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p. 23984 - 23988
(2013/11/19)
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- An unusual chemoselective hydrogenation of quinoline compounds using supported gold catalysts
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The pursuit of modern sustainable chemistry has stimulated the development of innovative catalytic processes that enable chemical transformations to be performed under mild and clean conditions with high efficiency. Herein, we report that gold nanoparticles supported on TiO2 catalyze the chemoselective hydrogenation of functionalized quinolines with H2 under mild reaction conditions. Our results point toward an unexpected role for quinolines in gold-mediated hydrogenation reactions, namely that of promoter; this is in stark contrast to what prevails in the traditional noble metal Pd-, Pt-, and Ru-based catalyst systems, in which quinolines and their derivatives typically act as poisons. As a result of the remarkable promotional effect of quinoline molecules to H2 activation over supported gold, the transformation can proceed smoothly under very mild conditions (even at temperatures as low as 25 °C). Of practical significance is that various synthetically useful functional groups including halogens, ketone, and olefin remain intact during the hydrogenation of quinolines. Moreover, the protocol also shows promise for the regiospecific hydrogenation of the heterocyclic ring of a variety of other biologically important heteroaromatic nitrogen compounds, such as isoquinoline, acridine, and 7,8-benzoquinoline, in a facile manner. Apart from its importance in catalytic hydrogenation, we believe that this intriguing self-promoted effect by reactant molecules may have fundamental implications for the broad field of gold catalysis and form the basis for development of new catalytic procedures for other key transformations.
- Ren, Dong,He, Lin,Yu, Lei,Ding, Ran-Sheng,Liu, Yong-Mei,Cao, Yong,He, He-Yong,Fan, Kang-Nian
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p. 17592 - 17598,7
(2012/12/12)
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- Facile synthesis of tricyclic oxazino- or oxazepino-fused tetrahydroquinolines via intramolecular reductive amidation
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Reductive cyclization of -(8-quinolyloxy)alkyl esters by zinc in acetic acid is shown to constitute a convenient methodology for the synthesis of oxazino- or oxazepino-fused tetrahydroquinolines. It is operationally simple, requires a short reaction time, and provides excellent yields. Georg Thieme Verlag Stuttgart ? New York.
- Mondal, Shyamal,Maity, Arindam,Naskar, Subhendu,Paira, Rupankar,Hazra, Abhijit,Sahu, Krishnendu B.,Saha, Pritam,Das, Saktipada,Banerjee, Sukdeb,Mondal, Nirup B.
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scheme or table
p. 2079 - 2084
(2011/08/03)
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- A highly efficient and widely functional-group-tolerant catalyst system for copper(I)-catalyzed S-arylation of thiols with aryl halides
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A mild, general, and efficient copper-catalyzed system for C-S bond formation with high chemoselectivity and wide functional group tolerance is developed. With CuBr as catalyst and 1,2,3,4-tetrahydro-8-hydroxy-quinoline as ligand, the S-arylation of thiols with aryl halides performed well, the activated aryl iodides could take place even at room temperature, and the activated aryl bromides and chlorides give the corresponding products with good to excellent yields as well.
- Feng, Yang,Wang, Huifeng,Sun, Fangfang,Li, Yaming,Fu, Xinmei,Jin, Kun
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supporting information; experimental part
p. 9737 - 9741
(2010/02/27)
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- 1,2,3,4-Tetrahydro-8-hydroxyquinoline-promoted copper-catalyzed coupling of nitrogen nucleophiles and aryl bromides
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(Chemical Equation Presented) Based on the dramatic accelerating effect of 2-aminophenol, three ligands derived from 2-aminophenol were developed. Copper-catalyzed coupling reaction of nitrogen-containing nucleophiles with aryl bromides was efficiently carried out under mild conditions using 1,2,3,4-tetrahydro-8-hydroxyquinoline as a novel, simple, and versatile ligand.
- Wang, Huifeng,Li, Yaming,Sun, Fangfang,Feng, Yang,Jin, Kun,Wang, Xiuna
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supporting information; experimental part
p. 8639 - 8642
(2009/04/04)
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- Synthesis and SAR of novel histamine H3 receptor antagonists
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The synthesis and biological evaluation of novel tetrahydroisoquinoline, tetrahydroquinoline, and tetrahydroazepine antagonists of the human and rat H3 receptors are described. The substitution around these rings as well as the nature of the substituent on nitrogen is explored. Several compounds with high affinity and selectivity for the human and rat H3 receptors are reported.
- Jesudason, Cynthia D.,Beavers, Lisa S.,Cramer, Jeffrey W.,Dill, Joelle,Finley, Don R.,Lindsley, Craig W.,Stevens, F. Craig,Gadski, Robert A.,Oldham, Samuel W.,Pickard, R. Todd,Siedem, Christopher S.,Sindelar, Dana K.,Singh, Ajay,Watson, Brian M.,Hipskind, Philip A.
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p. 3415 - 3418
(2007/10/03)
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- Solvent dependent regioselective hydrogenation of substituted quinolines
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Various substituted quinolines have been reduced under H2 using Rh/Al2O3. Using methanol as solvent leads selectively to the 1,2,3,4-tetrahydroquinoline derivatives whereas in hexafluoroisopropanol the decahydro compounds are obtained.
- Fache, Fabienne
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p. 2827 - 2829
(2007/10/03)
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- Regioselective reduction of quinolines and related systems to 1,2,3,4-tetrahydro derivatives with zinc borohydride
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A simple and convenient procedure for the reduction of quinolines, isoquinoline and other related systems to the corresponding 1,2,3,4-tetrahydro derivatives has been developed in the presence of catalytic amount of N,N-dimethyl aniline under sonication.
- Ranu, Brindaban C.,Jana, Umasish,Sarkar, Arunkanti
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p. 485 - 492
(2007/10/03)
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- 1,2,3,4-tetrahydro-8-quinolinol derivatives and anti-allergic use thereof
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Leukotriene biosynthesis in macrophage cells is inhibited by compounds having the formula STR1 and pharmaceutically acceptable salts thereof, wherein R1 and R2 are each hydrogen and R3 is alkyl or arylalkyl; R1
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- Selectivity in the Hydrogenation of 6- and 8-Substituted-quinolines
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Quinoline (1) and the 6- or 8-substituted-quinolines (2)-(14) (R = Me, Pri, But, Ph, OMe, OH, CF3, or F) were hydrogenated catalytically on platinum under either weakly basic (solvent MeOH) or strongly acidic (solvent CF3CO2H) conditions.In methanol the only product was the corresponding 1,2,3,4-tetrahydro-compound.In trifluoroacetic acid, compounds hydrogenated in the benzene ring were isolated as major products; both electron-withdrawing and electron-donating substituents at C-6 or C-8 cause (sometimes drastic) reduction in yield.The products were characterized by their 1H and 13C n.m.r. spectra.
- Hoenel, Michael,Vierhapper, Friedrich W.
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p. 1933 - 1939
(2007/10/02)
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