- Potent mutagenic potential of 4-methylquinoline: Metabolic and mechanistic considerations
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4-Methylquinoline (4-MeQ) showed an extraordinarily potent mutagenicity when compared to quinolone and isomeric methylquinolines. The major metabolite of 4-MeQ was 4- hydroxymethylquinoline, which was not mutagenic under the assay condition employed. Deuteration of the methyl group of 4-MeQ resulted in a decrease in the amount of the hydroxymethyl metabolic and an increase in mutagenicity, indicating that hydroxylation of the substituent methyl group is a detoxication process. A 3-chloro derivative of 4-MeQ was proven to be non-mutagenic. 4-Ethyl- quinoline, as well as 4-hydroxymethylquinoline, was much less mutagenic than 4-MeQ. Taking account of the structure-mutagenicity relationship, a possible mechanism is proposed for the potent mutagenic potential of 4-MeQ.
- Saeki, Ken-Ichi,Takahashi, Kazuhiko,Kawazoe, Yutaka
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Read Online
- Method for realizing oxidative dehydrogenation of nitrogen-containing heterocyclic ring by using biomass-based carbon material
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The invention provides a method for realizing oxidative dehydrogenation of a nitrogen-containing heterocyclic ring by using a biomass-based carbon material, and belongs to the field of organic synthesis. According to the method, the raw materials of the biomass-based carbon material comprise wheat, sorghum, rice, corn straw, wheat straw, peanut shells, sesame shells, bean shells and the like, and are crushed and then ground into powder, the powder is fully mixed with an inorganic alkali, and calcination is performed in an inert gas atmosphere to prepare the biomass-based carbon material; and by using air as an oxygen source, at a temperature of 50-120 DEG C, oxidative dehydrogenation of nitrogen-containing heterocyclic compounds to synthesize quinoline compounds, isoquinoline compounds, acridine compounds, quinazoline compounds, indole compounds, imine compounds, and even quinoline compounds with pharmaceutical activity can be achieved. According to the present invention, easily available wheat flour is adopted as a raw material to prepare a non-metal catalyst, the alkali is not added during the reaction process, and a remarkable industrial application prospect is achieved.
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Paragraph 0010-0013; 0016-0017
(2021/06/26)
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- Highly Chemoselective Deoxygenation of N-Heterocyclic N-Oxides Using Hantzsch Esters as Mild Reducing Agents
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Herein, we disclose a highly chemoselective room-temperature deoxygenation method applicable to various functionalized N-heterocyclic N-oxides via visible light-mediated metallaphotoredox catalysis using Hantzsch esters as the sole stoichiometric reductant. Despite the feasibility of catalyst-free conditions, most of these deoxygenations can be completed within a few minutes using only a tiny amount of a catalyst. This technology also allows for multigram-scale reactions even with an extremely low catalyst loading of 0.01 mol %. The scope of this scalable and operationally convenient protocol encompasses a wide range of functional groups, such as amides, carbamates, esters, ketones, nitrile groups, nitro groups, and halogens, which provide access to the corresponding deoxygenated N-heterocycles in good to excellent yields (an average of an 86.8% yield for a total of 45 examples).
- An, Ju Hyeon,Kim, Kyu Dong,Lee, Jun Hee
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supporting information
p. 2876 - 2894
(2021/02/01)
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- Covalent Organic Frameworks toward Diverse Photocatalytic Aerobic Oxidations
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Photoactive two-dimensional covalent organic frameworks (2D-COFs) have become promising heterogenous photocatalysts in visible-light-driven organic transformations. Herein, a visible-light-driven selective aerobic oxidation of various small organic molecules by using 2D-COFs as the photocatalyst was developed. In this protocol, due to the remarkable photocatalytic capability of hydrazone-based 2D-COF-1 on molecular oxygen activation, a wide range of amides, quinolones, heterocyclic compounds, and sulfoxides were obtained with high efficiency and excellent functional group tolerance under very mild reaction conditions. Furthermore, benefiting from the inherent advantage of heterogenous photocatalysis, prominent sustainability and easy photocatalyst recyclability, a drug molecule (modafinil) and an oxidized mustard gas simulant (2-chloroethyl ethyl sulfoxide) were selectively and easily obtained in scale-up reactions. Mechanistic investigations were conducted using radical quenching experiments and in situ ESR spectroscopy, all corroborating the proposed role of 2D-COF-1 in photocatalytic cycle.
- Liu, Shuyang,Tian, Miao,Bu, Xiubin,Tian, Hua,Yang, Xiaobo
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supporting information
p. 7738 - 7744
(2021/05/07)
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- Highly Ordered Mesoporous Cobalt Oxide as Heterogeneous Catalyst for Aerobic Oxidative Aromatization of N-Heterocycles
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N-heterocycles are key structures for many pharmaceutical intermediates. The synthesis of such units normally is conducted under homogeneous catalytic conditions. Among all methods, aerobic oxidative aromatization is one of the most effective. However, in homogeneous conditions, catalysts are difficult to be recycled. Herein, we report a heterogeneous catalytic strategy with a mesoporous cobalt oxide as catalyst. The developed protocol shows a broad applicability for the synthesis of N-heterocycles (32 examples, up to 99 % yield), and the catalyst presents high turnover numbers (7.41) in the absence of any additives. Such a heterogenous approach can be easily scaled up. Furthermore, the catalyst can be recycled by simply filtration and be reused for at least six times without obvious deactivation. Comparative studies reveal that the high surface area of mesoporous cobalt oxide plays an important role on the catalytic reactivity. The outstanding recycling capacity makes the catalyst industrially practical and sustainable for the synthesis of diverse N-heterocycles.
- Cao, Yue,Wu, Yong,Zhang, Yuanteng,Zhou, Jing,Xiao, Wei,Gu, Dong
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p. 3679 - 3686
(2021/06/18)
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- Iron(II)-Catalyzed Aerobic Biomimetic Oxidation of N-Heterocycles
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Herein, an iron(II)-catalyzed biomimetic oxidation of N-heterocycles under aerobic conditions is described. The dehydrogenation process, involving several electron-transfer steps, is inspired by oxidations occurring in the respiratory chain. An environmentally friendly and inexpensive iron catalyst together with a hydroquinone/cobalt Schiff base hybrid catalyst as electron-transfer mediator were used for the substrate-selective dehydrogenation reaction of various N-heterocycles. The method shows a broad substrate scope and delivers important heterocycles in good-to-excellent yields.
- Manna, Srimanta,Kong, Wei-Jun,B?ckvall, Jan-E.
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supporting information
p. 13725 - 13729
(2021/09/08)
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- Generation of Alkyl Radical through Direct Excitation of Boracene-Based Alkylborate
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The generation of tertiary, secondary, and primary alkyl radicals has been achieved by the direct visible-light excitation of a boracene-based alkylborate. This system is based on the photophysical properties of the organoboron molecule. The protocol is applicable to decyanoalkylation, Giese addition, and nickel-catalyzed carbon-carbon bond formations such as alkyl-aryl cross-coupling or vicinal alkylarylation of alkenes, enabling the introduction of various C(sp3) fragments to organic molecules.
- Hashizume, Daisuke,Hosoya, Takamitsu,Nakamura, Kei,Ohmiya, Hirohisa,Sato, Yukiya,Sumida, Yuto
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supporting information
p. 9938 - 9943
(2020/06/27)
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- Gold-Catalyzed Iminations of Terminal Propargyl Alcohols with Anthranils with Atypical Chemoselectivity for C(1)-Additions and 1,2-Carbon Migration
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This work reports gold-catalyzed iminations of terminal propargyl alcohols with anthranils or isoxazoles to yield E-configured α-amino-2-en-1-ones and -1-als with complete chemoselectivity. These catalytic iminations occur exclusively with C(1)-nucleophilic additions on terminal alkynes, in contrast to a typical C(2)-route. For 3,3-dialkylprop-1-yn-3-ols, a methyl substituent is superior to long alkyl chains as the 1,2-migration groups toward α-imino gold carbenes. For secondary prop-1-yn-3-ols, phenyl, vinyl, and cyclopropyl substituents are better than hydrogen as the migrating groups, obviating typical gold carbene reactions. DFT calculations have been performed to rationalize the observed C(1)-regioselectivity and the preferable cyclopropyl migration based on gold carbene pathways.
- Skaria, Manisha,More, Sayaji Arjun,Kuo, Tung-Chun,Cheng, Mu-Jeng,Liu, Rai-Shung
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p. 3600 - 3608
(2020/03/04)
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- Nickel/Photoredox-Catalyzed Methylation of (Hetero)aryl Chlorides Using Trimethyl Orthoformate as a Methyl Radical Source
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Methylation of organohalides represents a valuable transformation, but typically requires harsh reaction conditions or reagents. We report a radical approach for the methylation of (hetero)aryl chlorides using nickel/photoredox catalysis wherein trimethyl orthoformate, a common laboratory solvent, serves as a methyl source. This method permits methylation of (hetero)aryl chlorides and acyl chlorides at an early and late stage with broad functional group compatibility. Mechanistic investigations indicate that trimethyl orthoformate serves as a source of methyl radical via β-scission from a tertiary radical generated upon chlorine-mediated hydrogen atom transfer.
- Kariofillis, Stavros K.,Shields, Benjamin J.,Tekle-Smith, Makeda A.,Zacuto, Michael J.,Doyle, Abigail G.
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supporting information
p. 7683 - 7689
(2020/04/22)
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- Rh-Catalyzed C-H Amination/Annulation of Acrylic Acids and Anthranils by Using -COOH as a Deciduous Directing Group: An Access to Diverse Quinolines
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A method for the synthesis of diverse polysubstituted quinolines from readily available acrylic acids and anthranils has been developed. The weakly coordinating -COOH directing group, which can be tracelessly removed in the cascade cyclization, is essential for this reaction. Diverse polysubstituted quinolines were obtained under mild reaction conditions with simple H2O and CO2 as byproducts. More importantly, 1,2,3,4-tetrahydroacridine, which is the core skeleton of tacrine (an Alzheimer's disease drug), was conveniently synthesized.
- Gao, Yang,Nie, Jianhong,Li, Yibiao,Li, Xianwei,Chen, Qian,Huo, Yanping,Hu, Xiao-Qiang
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supporting information
p. 2600 - 2605
(2020/04/02)
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- Catalytic Aerobic Dehydrogenatin of N-Heterocycles by N-Hydoxyphthalimide
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Catalytic methods for the aerobic dehydrogenation of N-heterocycles are reported. In most cases, indoles are accessed efficiently from indolines using catalytic N-hydroxyphthalimide (NHPI) as the sole additive under air. Further studies revealed an improved catalytic system of NHPI and copper for the preparation of other heteroaromatics, for example quinolines. (Figure presented.).
- Chen, Weidong,Tang, Hao,Wang, Weilin,Fu, Qiang,Luo, Junfei
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supporting information
p. 3905 - 3911
(2020/08/10)
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- Method for preparation of quinoline compounds
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The invention discloses a green preparation method of quinoline compounds. According to the method, cheap and easily available copper salt and N-hydroxyphthalimide are used as catalysts, oxygen is used as an oxidizing agent, oxidation of tetrahydroquinoline compounds is performed in an organic solvent, and synthesis of quinoline compounds is realized. The method has the advantages of simple reaction operation, low reaction cost, high yield, low metal pollution and the like.
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Paragraph 0040-0042
(2020/11/12)
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- Visible-Light-Promoted Efficient Aerobic Dehydrogenation of N-Heterocycles by a Tiny Organic Semiconductor Under Ambient Conditions
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An efficient reusable catalytic system has been developed based on perylene diimide (PDI) organic semiconductor for the aerobic dehydrogenation of N-heterocycles with visible light. This practical catalytic system without any additives proceeds under ambient conditions. The minute aggregates of PDI molecules on the surface of SiO2 nanospheres form tiny organic semiconductors, resulting in high-efficiency photo-oxidative activity. Notably, the robustness of this method is demonstrated by the synthesis of a wide range of N-heteroarenes, gram-scale experiments as well as reusability tests.
- Su, Chenliang,Yu, Kunyi,Zhang, Hanjie,Zhu, Yongfa
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supporting information
p. 1956 - 1960
(2020/04/10)
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- Iodine-catalyzed convergent aerobic dehydro-aromatization toward benzazoles and benzazines
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An iodine-catalyzed aerobic dehydro-aromatization has been developed, providing straightforward and efficient access to various benzoazoles and benzoazines. The present transition-metal-free protocol enables the dehydro-aromatization of tetrahydrobenzazoles and tetrahydroquinolines with molecular oxygen as the green oxidant, along with some other N-heterocycles. Hence, a broad range of heteroaromatic compounds are generated in moderate to good yields under facile reaction conditions.
- Chen, Shanping,Deng, Guo-Jun,Jiang, Pingyu,Ni, Penghui,Tuo, Xiaolong,Wang, Xiaodong
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p. 8348 - 8351
(2020/03/11)
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- CONVERSION OF TETRAHYDROQUINOLINE DERIVATIVES TO QUINOLINE USING AZOCOMPOUND
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The present invention relates to a method of converting tetrahydroquinoline derivatives into quinoline using an azo compound and, more specifically, to a conversion method which is performed in a deuterium chloroform (CDCl_3) or chloroform (CHCl_3) solution including dialkyl azodicarboxylate, which is a method of producing quinoline through a dehydrogenation reaction of 1,2,3,4-tetrahydroquinoline. According to the present invention, a dehydrogenation reaction rate is dependent on the electronic and steric properties of used dialkyl azodicarboxylate; and chloroform shows better results than other substances in solvents screened with diethyl azodicarboxylate. Various types of 1,2,3,4-tetrahydroquinoline undergo the dehydration reaction of the present invention to produce the corresponding quinoline in a yield of at least 90%; and diethyl hydrazo dicarboxylate, which is a reduced form of diethyl azodicarboxylate, is readily separated and recyclable.COPYRIGHT KIPO 2020
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Paragraph 0041-0042; 0056; 0112-0116
(2020/03/10)
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- Palladium-Catalyzed Methylation of Aryl, Heteroaryl, and Vinyl Boronate Esters
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A method for the direct methylation of aryl, heteroaryl, and vinyl boronate esters is reported, involving the reaction of iodomethane with aryl-, heteroaryl-, and vinylboronate esters catalyzed by palladium and PtBu2Me. This transformation occurs with a remarkably broad scope and is suitable for late-stage derivatization of biologically active compounds via the boronate esters. The unique capabilities of this method are demonstrated by combining carbon-boron bond-forming reactions with palladium-catalyzed methylation in a tandem transformation.
- Haydl, Alexander M.,Hartwig, John F.
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supporting information
p. 1337 - 1341
(2019/02/26)
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- Potassium tert-Butoxide-Promoted Acceptorless Dehydrogenation of N-Heterocycles
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Potassium tert-butoxide-promoted acceptorless dehydrogenation of N-heterocycles was efficiently realized for the generation of N-heteroarenes and hydrogen gas under transition-metal-free conditions. In the presence of KOtBu base, a variety of six- and five-membered N-heterocyclic compounds efficiently underwent acceptorless dehydrogenation to afford the corresponding N-heteroarenes and H2 gas in o-xylene at 140 °C. The present protocol provides a convenient route to aromatic nitrogen-containing compounds and H2 gas. (Figure presented.).
- Liu, Tingting,Wu, Kaikai,Wang, Liandi,Yu, Zhengkun
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supporting information
p. 3958 - 3964
(2019/08/01)
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- Corrigendum: Organo-Photoredox Catalyzed Oxidative Dehydrogenation of N-Heterocycles (Chemistry - A European Journal, (2017), 23, 57, (14167-14172), 10.1002/chem.201703642)
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The authors have been alerted to an error that was unfortunately missed at the time of publication. Table was duplicated with Table 4. The correct version of Table 2 is shown below. The authors apologise for any inconvenience caused. Organo-photoredox catalyzed oxidative dehydrogenation of tetrahydroquinolines (THQ).[a,b] (Table presented.) [a] Reaction conditions: 1 (0.5 mmol), rose bengal (1.0 mol %), N,N-dimethylacetamide (2.0 mL), open air atmosphere under visible-light irradiation at room temperature for 24 h. [b] Isolated yields. [c] 0.1 mol % of photoredox catalyst for 28 h.
- Sahoo, Manoj K.,Jaiswal, Garima,Rana, Jagannath,Balaraman, Ekambaram
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p. 7038 - 7038
(2019/05/17)
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- Visible-Light Photocatalyzed Deoxygenation of N-Heterocyclic N-Oxides
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A scalable and operationally simple method is described that allows for the chemoselective deoxygenation of a wide range of N-heterocyclic N-oxides (a total of 36 examples). This visible-light-induced protocol features the use of only commercially available reagents, room-temperature conditions, and unprecedented chemoselective removal of the oxygen atom in a quinoline N-oxide in the presence of a pyridine N-oxide in the same molecule through the judicious selection of a photocatalyst.
- Kim, Kyu Dong,Lee, Jun Hee
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supporting information
p. 7712 - 7716
(2019/01/03)
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- Pd-Catalyzed Alkylation of (Iso)quinolines and Arenes: 2-Acylpyridine Compounds as Alkylation Reagents
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The first Pd-catalyzed alkylation of (iso)quinolines and arenes is reported. The readily available and bench-stable 2-acylpyridine compounds were used as an alkylation reagent to form the structurally versatile alkylated (iso)quinolines and arenes. The method affords a convenient pathway for the introduction of alkyl groups into organic molecules.
- Wu, Qingsong,Han, Shuaijun,Ren, Xiaoxiao,Lu, Hongtao,Li, Jingya,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
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supporting information
p. 6345 - 6348
(2018/10/20)
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- Efficient dehydrogenation of 1,2,3,4-tetrahydroquinolines mediated by dialkyl azodicarboxylates
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Various dialkyl azodicarboxylates were investigated for the dehydrogenation of 1,2,3,4-tetrahydroquinolines to quinolines. The dehydrogenation rates varied according to the electronic and steric nature of the used dialkyl azodicarboxylates. Among solvents screened with diethyl azodicarboxylate, chloroform exhibited superior results to others. A variety of 1,2,3,4-tetrahydroquinolines underwent the present dehydrogenation to produce the corresponding quinolines. Diethyl hydrazodicarboxylate, which is a reduced species of diethyl azodicarboxylate, was easily separated for recycle.
- Bang, Saet Byeol,Kim, Jinho
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supporting information
p. 1291 - 1298
(2018/04/05)
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- Acceptorless Dehydrogenation of N-Heterocycles and Secondary Alcohols by Ru(II)-NNC Complexes Bearing a Pyrazoyl-indolyl-pyridine Ligand
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Ruthenium(II) hydride complexes bearing a pyrazolyl-(2-indol-1-yl)-pyridine ligand were synthesized and structurally characterized by NMR analysis and X-ray single crystal crystallographic determinations. These complexes efficiently catalyzed acceptorless dehydrogenation of N-heterocycles and secondary alcohols, respectively, exhibiting highly catalytic activity with a broad substrate scope. The present work has established a strategy to construct highly active transition metal complex catalysts and provides an atom-economical and environmentally benign protocol for the synthesis of aromatic N-heterocyclic compounds and ketones.
- Wang, Qingfu,Chai, Huining,Yu, Zhengkun
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p. 584 - 591
(2018/03/08)
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- Electrochemical Acceptorless Dehydrogenation of N-Heterocycles Utilizing TEMPO as Organo-Electrocatalyst
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Catalytic acceptorless dehydrogenation (CAD) has been a basically important organic transformation to ubiquitous unsaturated compounds without the usage of a sacrificial hydrogen acceptor. In this work, we successfully developed the first electrochemical acceptorless dehydrogenation (ECAD) of N-heterocycles using TEMPO as the organo-electrocatalyst. We have achieved the catalytic dehydrogenation of N-heterocycles in an anode and the release of H2 in a cathode using an undivided-cell system. A variety of six-membered and five-membered nitrogen-heteroarenes can be synthesized in good yields in this system. In addition, this protocol can also be used in the application of important molecular synthesis. Our electrochemical strategy provides a mild and metal-free route for (hetero)aromatic compounds synthesis via the CAD strategy.
- Wu, Yong,Yi, Hong,Lei, Aiwen
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p. 1192 - 1196
(2018/02/14)
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- Oxidation Potential Tunable Organic Molecules and Their Catalytic Application to Aerobic Dehydrogenation of Tetrahydroquinolines
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In this work, oxidation potential tunable organic molecules, alkyl 2-phenyl hydrazocarboxylates, were disclosed. The exquisite tuning of their oxidation potentials facilitated a catalytic dehydrogenation of 1,2,3,4-tetrahydroquinolines in the presence of Mn(Pc) and O2.
- Jung, Dahyeon,Jang, Seol Heui,Yim, Taeeun,Kim, Jinho
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supporting information
p. 6436 - 6439
(2018/10/15)
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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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- Zinc cation supported on carrageenan magnetic nanoparticles: A novel, green and efficient catalytic system for one-pot three-component synthesis of quinoline derivatives
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This is the first report of supporting zinc cation on ?-carrageenan/Fe3O4 magnetic nanoparticles. The structural and magnetic properties of this hybrid (Zn2 +/?-carrageenan/Fe3O4 nanoparticles) were identified using various techniques. This green and efficient catalytic system was applied in the synthesis of biologically important quinolines. The products were obtained in good to high yields (52–95%) from a one-pot reaction procedure involving aromatic aldehydes, enolizable aldehydes and aniline derivatives. Our method has many advantages such as mild reaction conditions, easy work-up, use of a reusable magnetic catalyst and high yields of products.
- Keshavarzipour, Fariba,Tavakol, Hossein
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- Method for compounding quinoline compound in manner of oxidative dehydrogenation of tetrahydroquinoline compound through visible light catalysis
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The invention discloses a method for compounding a quinoline compound in the manner of oxidative dehydrogenation of a tetrahydroquinoline compound through visible light catalysis. The method comprises the following steps: utilizing oxygen to replace peroxide as an oxidizing agent; taking polysubstituted BODIPY organic compound as a photocatalyst; catalyzing the oxidative dehydrogenation of 1,2,3,4-tetrahydroquinoline compound and compounding the quinoline compound. Compared with the present compounding method, the method has the advantages of mild reaction condition, metal-free photocatalyst used in the reaction, less dosage of the catalyst, high catalytic efficiency, stabilization, high efficiency, simple operation, environmental protection, high conversion rate of products and excellent selectivity.
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Paragraph 0018; 0019; 0020-0023; 0030-0050; 0071-0074
(2017/10/07)
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- Nickel-catalyzed methylation of aryl halides/tosylates with methyl tosylate
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This work describes the cross-electrophile methylation of aryl bromides and aryl tosylates with methyl tosylate. The mild reaction conditions allow effective methylation of a wide set of heteroaryl electrophiles and dimethylation of dibromoarenes.
- Wang, Jiawang,Zhao, Jianhong,Gong, Hegui
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supporting information
p. 10180 - 10183
(2017/09/23)
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- Acceptorless Dehydrogenation of N-Heterocycles by Merging Visible-Light Photoredox Catalysis and Cobalt Catalysis
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Herein, the first acceptorless dehydrogenation of tetrahydroquinolines (THQs), indolines, and other related N-heterocycles, by merging visible-light photoredox catalysis and cobalt catalysis at ambient temperature, is described. The potential applications to organic transformations and hydrogen-storage materials are demonstrated. Primary mechanistic investigations indicate that the catalytic cycle occurs predominantly by an oxidative quenching pathway.
- He, Ke-Han,Tan, Fang-Fang,Zhou, Chao-Zheng,Zhou, Gui-Jiang,Yang, Xiao-Long,Li, Yang
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supporting information
p. 3080 - 3084
(2017/03/14)
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- Method for preparing quinoline derivative by catalyzing oxidative dehydrogenation of nitrogen-containing heterocyclic ring through carbon nitride material
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The invention belongs to the field of chemical synthesis, and particularly relates to a method for preparing a quinoline derivative by catalyzing oxidative dehydrogenation of a nitrogen-containing heterocyclic ring through a carbon nitride material. The carbon nitride material is prepared by using a nitrogen-containing organic macrocyclic compound as a precursor and calcining in an inert atmosphere. During a reaction, oxygen or air is used as an oxidant, and in the presence or absence of a solvent, the reaction is performed at 50-120 DEG C and the carbon nitrogen material can convert the nitrogen-containing heterocyclic ring into the corresponding quinoline derivative. According to the invention, no metal is introduced into a reaction system, and the method is easy to amplify; after being recycled for at least 9 times, a catalyst still maintain good selectivity and activity; therefore, the method has a significant practical prospect during industrial production.
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Paragraph 0022; 0023
(2017/08/29)
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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 catalyzing nitrogen heterocyclic ring compound for oxidative dehydrogenation with hydrotalcite-like material
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The invention relates to a method for catalyzing a nitrogen heterocyclic ring compound for oxidative dehydrogenation with a hydrotalcite-like material, and belongs to the application aspect of a hydrotalcite-like component. The hydrotalcite-like component can be expressed as: A-MxM-LDHs (A=OH or CO3; M=Ni, Co, Cu, Mg or Zn; M=Fe, Mn, Al; M/M=(2 to 4)). Under existence of the catalyst and without adding any additives, oxidative dehydrogenation reaction is performed on the heterocyclic ring compound under a mild condition to prepare a corresponding aromatic compound. According to the method provided by the invention, the hydrotalcite-like material is based on non-noble metal, can be synthesized largely, and can be recycled; the method has the advantages of being high in catalytic reaction efficiency, mild in reaction condition, low in cost, easy to industrialize and the like.
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Paragraph 0048; 0049; 0050; 0051; 0052
(2017/10/27)
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- Palladium Nanoparticles Stabilized by Metal–Carbon Covalent Bonds as an Expeditious Catalyst for the Oxidative Dehydrogenation of Nitrogen Heterocycles
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The first method for the dehydrogenation of nitrogen heterocycles catalyzed by a palladium nanocatalyst was developed. Carbon–metal covalent-bond-stabilized nanoparticles were found to be efficient for the dehydrogenation process in the presence of tert-butyl hydroperoxide. A variety of N-heterocycles were transformed into functionalized quinolines in medium to excellent yields in water as the solvent under mild conditions by a simple operation.
- Sun, Xiao-Tao,Zhu, Jie,Xia, Yun-Tao,Wu, Lei
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p. 2463 - 2466
(2017/07/12)
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- MAGNETICALLY SEPARABLE IRON-BASED HETEROGENEOUS CATALYSTS FOR DEHYDROGENATION OF ALCOHOLS AND AMINES
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The present invention discloses an iron-based nitrogen doped graphene catalyst, process for preparation thereof and use of said catalyst in oxidant-free catalytic dehydrogenation of alcohols and amines to the corresponding carbonyl compounds, amines and N-heterocylic compounds with extraction of molecular hydrogen as the only by-product.
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Page/Page column 19; 20; 21; 22
(2016/12/22)
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- A Convenient Procedure for the Oxidative Dehydrogenation of N-Heterocycles Catalyzed by FeCl2/DMSO
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A convenient catalytic procedure has been developed for the oxidative dehydrogenations of N-heterocycles. Combining catalytic FeCl2 with DMSO yields a catalyst that promotes the dehydrogenation of tetrahydroquinolines and related heterocycles under 1 bar of O2, affording the corresponding N-heteroaromatic products in moderate yields.
- Zhou, Weiyou,Taboonpong, Piyada,Aboo, Ahmed Hamdoon,Zhang, Lingjuan,Jiang, Jun,Xiao, Jianliang
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supporting information
p. 1806 - 1809
(2016/07/16)
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- Metal-free aerobic one-pot synthesis of substituted/annulated quinolines from alcohols via indirect Friedl?nder annulation
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Metal-free, operationally simple, and highly efficient one-pot aerobic process for the synthesis of functionalized/annulated quinolines is devised from easily available 2-aminobenzyl alcohol/2-aminobenzophenones and alkyl/aryl alcohols for the first time. The process involves two sequential reactions, namely in situ aerial oxidation of alcohols to the corresponding aldehydes/ketones followed by Friedl?nder annulation.
- Anand, Namrata,Koley, Suvajit,Ramulu, B. Janaki,Singh, Maya Shankar
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supporting information
p. 9570 - 9574
(2015/09/28)
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- Synthesis of Quinolines from Allylic Alcohols via Iridium-Catalyzed Tandem Isomerization/Cyclization Combined with Potassium Hydroxide
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A new tandem catalytic process has been established for the synthesis of quinolines. This process utilizes the [IrCp?Cl2]2/KOH catalyzed isomerization/cyclization of allylic alcohols with 2-aminobenzyl alcohol. Both the secondary and primary allylic alcohols were investigated in this catalytic system to afford different substituted quinoline derivatives in moderate to good yields. A mechanism study showed the reaction following a tandem process integrating isomerization of allylic alcohols and oxidative cyclization of 2-aminobenzyl alcohol.
- Chen, Shu-Jie,Lu, Guo-Ping,Cai, Chun
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p. 976 - 984
(2015/03/30)
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- Synthesis and Characterization of Iron-Nitrogen-Doped Graphene/Core-Shell Catalysts: Efficient Oxidative Dehydrogenation of N-Heterocycles
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An important goal for nanocatalysis is the development of flexible and efficient methods for preparing active and stable core-shell catalysts. In this respect, we present the synthesis and characterization of iron oxides surrounded by nitrogen-doped-graphene shells immobilized on carbon support (labeled FeOx@NGr-C). Active catalytic materials are obtained in a simple, scalable and two-step method via pyrolysis of iron acetate and phenanthroline and subsequent selective leaching. The optimized FeOx@NGr-C catalyst showed high activity in oxidative dehydrogenations of several N-heterocycles. The utility of this benign methodology is demonstrated by the synthesis of pharmaceutically relevant quinolines. In addition, mechanistic studies prove that the reaction progresses via superoxide radical anions (·O2-).
- Cui, Xinjiang,Li, Yuehui,Bachmann, Stephan,Scalone, Michelangelo,Surkus, Annette-Enrica,Junge, Kathrin,Topf, Christoph,Beller, Matthias
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supporting information
p. 10652 - 10658
(2015/09/28)
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- Catalytic Aerobic Dehydrogenation of Nitrogen Heterocycles Using Heterogeneous Cobalt Oxide Supported on Nitrogen-Doped Carbon
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Dehydrogenation of (partially) saturated heterocycles provides an important route to heteroaromatic compounds. A heterogeneous cobalt oxide catalyst, previously employed for aerobic oxidation of alcohols and amines, is shown to be effective for aerobic dehydrogenation of various 1,2,3,4-tetrahydroquinolines to the corresponding quinolines. The reactions proceed in good yields under mild conditions. Other N-heterocycles are also successfully oxidized to their aromatic counterparts.
- Iosub, Andrei V.,Stahl, Shannon S.
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supporting information
p. 4404 - 4407
(2015/09/28)
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- Modular o-quinone catalyst system for dehydrogenation of tetrahydroquinolines under ambient conditions
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Quinolines are common pharmacophores present in numerous FDA-approved pharmaceuticals and other bioactive compounds. Here, we report the design and development of new o-quinone-based catalysts for the oxidative dehydrogenation of tetrahydroquinolines to afford quinolines. Use of a Co(salophen) cocatalyst allows the reaction to proceed efficiently with ambient air at room temperature. The utility of the catalytic method is demonstrated in the preparation of a number of medicinally relevant quinolines.
- Wendlandt, Alison E.,Stahl, Shannon S.
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supporting information
p. 11910 - 11913
(2014/10/16)
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- An unexpected one-pot synthesis of multi-substituted quinolines via a cascade reaction of Michael/Staudinger/aza-Wittig/aromatization of ortho-azido-β-nitro-styrenes with various carbonyl compounds
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Multi-substituted quinolines 3 were unexpectedly prepared from a cascade reaction of ortho-azido-β-nitro-styrenes with various carbonyl compounds. This method takes advantages of mild condition, simple work-up, high yield as well as wide substrate scope, which makes this method powerful for one-pot synthesis of multi-substituted quinolines.
- Yu, Zhi-Hua,Zheng, Hu-Fei,Yuan, Wei,Tang, Zi-Long,Zhang, Ai-Dong,Shi, De-Qing
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p. 8137 - 8141
(2013/09/02)
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- Acceptorless dehydrogenation of nitrogen heterocycles with a versatile iridium catalyst
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Gas up: A cyclometalated iridium complex is found to catalyze the dehydrogenation of various benzofused N-heterocycles, thus releasing H 2. Driven by as low as 0.1 mol % catalyst, the reaction affords quinolines, indoles, quinoxalines, isoquinolines, and β-carbolines in high yields. Copyright
- Wu, Jianjun,Talwar, Dinesh,Johnston, Steven,Yan, Ming,Xiao, Jianliang
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supporting information
p. 6983 - 6987
(2013/07/26)
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- A novel Friedlander-type synthesis of 3-aryl quinolines from 3-oxo-2,3-diaryl-propionaldehydes
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3-Aryl quinolines are readily synthesized by a novel Friedlaender-type reaction with 3-oxo-2,3-diaryl-propionaldehydes and 2-amino arylaldehydes. A preliminary mechanism of this novel one pot, two-step synthesis has been explored with the proofs of isolation of the enaminone intermediate and the eliminated benzoic acid in this reaction.
- Luo, Wanrong,Mu, Qiuchao,Qiu, Wenwei,Liu, Ting,Yang, Fan,Liu, Xiaofeng,Tang, Jie
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supporting information; experimental part
p. 7090 - 7095
(2011/10/07)
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- Ruthenium-catalysed synthesis of 2- and 3-substituted quinolines from anilines and 1,3-diols
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A straightforward synthesis of substituted quinolines is described by cyclocondensation of anilines with 1,3-diols. The reaction proceeds in mesitylene solution with catalytic amounts of RuCl3·xH 2O, PBu3 and MgBr2·OEt2. The transformation does not require any stoichiometric additives and only produces water and dihydrogen as byproducts. Anilines containing methyl, methoxy and chloro substituents as well as naphthylamines were shown to participate in the heterocyclisation. In the 1,3-diol a substituent was allowed in the 1- or the 2-position giving rise to 2- and 3-substituted quinolines, respectively. The best results were obtained with 2-alkyl substituted 1,3-diols to afford 3-alkylquinolines. The mechanism is believed to involve dehydrogenation of the 1,3-diol to the 3-hydroxyaldehyde which eliminates water to the corresponding α,β-unsaturated aldehyde. The latter then reacts with anilines in a similar fashion as observed in the Doebner-von Miller quinoline synthesis.
- Monrad, Rune Nygaard,Madsen, Robert
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body text
p. 610 - 615
(2011/02/28)
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- Cross-coupling reactions through the intramolecular activation of Alkyl(triorgano)silanes
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(Figure Presented) Cross-Si-ing the Jordan: Cross-coupling reactions of 2-(2-hydroxyprop-2-yl)phenylsubstituted alkylsilanes with a variety of aryl halides proceed in the presence of palladium and copper catalysts. The use of K3PO4 base allows for highly chemoselective alkyl coupling with both primary and secondary alkyl groups (Alk).
- Nakao, Yoshiaki,Takeda, Masahide,Matsumoto, Takuya,Hiyama, Tamejiro
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supporting information; scheme or table
p. 4447 - 4450
(2010/08/19)
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- Homogeneous catalytic system for reversible dehydrogenation-hydrogenation reactions of nitrogen heterocycles with reversible interconversion of catalytic species
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(Chemical Equation Presented) The first homogeneous catalytic system forthe efficient reversible dehydrogenation-hydrogenation reactions of nit rogen heterocycles in one flask has been developed using the pyridonate Cp*Ir complex as the single catalyst at relatively low temperature. The reversible catalytic reactions proceed with the reversible interconversion of catalytic species and can be nearly quantitatively repeated five times with almost no loss of efficiency. The remarkable feature of the present homogeneous catalytic system is that the reversible dehydrogenation-hydrogenation reactions proceed with the reversible interconversion ofthe catalytic species, depending on the absence or presence of hydrogen .
- Yamaguchi, Ryohei,Ikeda, Chikako,Takahashi, Yoshinori,Fujita, Ken-Ichi
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supporting information; scheme or table
p. 8410 - 8412
(2009/10/24)
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- Methyl transfer reaction from monomethyltin reagent under palladium(0) catalysis: A versatile method for labelling with carbon-11
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The 11C-monomethylstannate prepared from [11C]-methyl iodide and Lappert's stannylene, was subject to a palladium-mediated cross-coupling reaction with an aryl halide under ligand-free conditions, to afford easily purified 11C-methyl(hetero)arenes in high radiochemical yields. The Royal Society of Chemistry 2006.
- Huiban, Mickael,Huet, Aline,Barre, Louisa,Sobrio, Franck,Fouquet, Eric,Perrio, Cecile
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- 4-Quinolylmethyl and 1-naphthylmethyl as benzyl-type protecting groups of carboxylic acids removable by homogeneous palladium-catalyzed hydrogenolysis
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4-Quinolylmethyl (4-QUI) esters are reduced by palladium-catalyzed hydrogenolysis by formate anion. The reaction conditions are compatible with reducible substituents or functional groups as aromatic bromo, alkene, aldehyde, ketone, nitrile, ethyl and benzyl esters. An allyl ester is cleaved selectively in the presence of a 4-QUI ester. 1-Naphthylmethyl (1-NAP) esters of α-amino acids could be deprotected without any racemization by the same methodology. (C) 2000 Elsevier Science Ltd.
- Boutros, André,Legros, Jean-Yves,Fiaud, Jean-Claude
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p. 2239 - 2246
(2007/10/03)
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- Reactivity of quinoline- and isoquinoline-based heteroaromatic substrates in palladium(0)-catalyzed benzylic nucleophilic substitution
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(Formula presented) Quinolylmethyl, 1-(isoquinolyl)ethyl, and 1-(quinolyl)ethyl acetates reacted with dimethylmalonate anion in the presence of a Pd(0) catalyst to give products of nucleophilic substitution and/or byproducts, depending upon the substitution pattern. The observed side reactions were reduction in the case of primary acetates and elimination or elimination/Michael-type addition sequence for secondary substrates.
- Legros, Jean-Yves,Primault, Gaelle,Toffano, Martial,Riviere, Marie-Alix,Fiaud, Jean-Claude
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p. 433 - 436
(2007/10/03)
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