- Efficient Organoruthenium Catalysts for α-Alkylation of Ketones and Amide with Alcohols: Synthesis of Quinolines via Hydrogen Borrowing Strategy and their Mechanistic Studies
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A new family of phosphine free organometallic ruthenium(II) catalysts (Ru1–Ru4) supported by bidentate NN Schiff base ligands (L1–L4 where L1=N,N-dimethyl-4-((2-phenyl-2-(pyridin-2-ylmethyl)hydrazineylidene)methyl) aniline, L2=N,N-diethyl-4-((2-phenyl-2-(pyridin-2-ylmethyl)hydrazineylidene)methyl)aniline, L3=N,N-dimethyl-4-((2-phenyl-2-(pyridin-2-yl)hydrazineylidene)methyl)- aniline and L4=N,N-diethyl-4-((2-phenyl-2-(pyridin-2-yl)hydrazineylidene)methyl) aniline) was prepared and characterized. These half-sandwich complexes acted as catalysts for C?C bond formation and exhibited excellent performance in the dehydrogenative coupling of ketones and amides. In the synthesis of C–C bonds, alcohols were utilized as the alkylating agent. A broad range of substrates, including sterically hindered ketones and alcohols, were well tolerated under the optimized conditions (TON up to 47000 and TOF up to 11750 h?1). This ruthenium (II) catalysts were also active towards the dehydrogenative cyclization of o-amino benzyl alcohol for the formation of quinolines derivatives. Various polysubstituted quinolines were synthesized in moderate to excellent yields (TON up to 71000 and TOF up to 11830 h?1). Control experiments were carried out and the ruthenium hydride intermediate was characterized to support the reaction mechanism and a probable reaction pathway of dehydrogenative coupling for the C?C bond formation has been proposed.
- Maji, Ankur,Singh, Anshu,Singh, Neetu,Ghosh, Kaushik
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p. 3108 - 3125
(2020/05/18)
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- Pr2O3 Supported Nano-layered Ruthenium Catalyzed Acceptorless Dehydrogenative Synthesis of 2-Substituted Quinolines and 1,8-Naphthyridines from 2-Aminoaryl Alcohols and Ketones
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Pr2O3 supported Ru nanolayers and Ru nanoparticles catalysts were examined for the synthesis of quinolines. The Ru nanolayer was most active catalyst and showed a broad substrate scope. Structure-activity relationship demonstrated that the metallic state and morphology of Ru as well as the basic site of Pr2O3 were indispensable factors of this catalytic system.
- Chaudhari, Chandan,Sato, Katsutoshi,Ogura, Yuta,Miayahara, Shin-Ichiro,Nagaoka, Katsutoshi
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p. 2198 - 2202
(2020/03/24)
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- Green synthesis of silver nanoparticles using green alga (Chlorella vulgaris) and its application for synthesis of quinolines derivatives
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Nanoparticles have been used century ago but have regained their importance in recent years being simple, ecofriendly, pollutant free, nontoxic, low-cost approach, and due good atom economy. In this report, we have demonstrated the synthesis of silver nanoparticles using green algae (Chlorella vulgaris) which in turn was used for synthesis of biologically important quinolines. Algal extract was prepared and treated with silver nitrate solution for the synthesis of silver nanoparticles. Synthesized nanoparticles were characterized with the help of analytical tools like UV, FTIR, X-ray, and SEM and used as a catalyst for the synthesis of quinolines.
- Mahajan, Akhil,Arya, Anju,Chundawat, Tejpal Singh
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supporting information
p. 1926 - 1937
(2019/05/17)
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- Deracemization of Phenyl-Substituted 2-Methyl-1,2,3,4-Tetrahydroquinolines by a Recombinant Monoamine Oxidase from Pseudomonas monteilii ZMU-T01
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A monoamine oxidase (MAO5) from Pseudomonas monteilii ZMU-T01 was first heterologously expressed in Escherichia coli BL21(DE3) and then used as a biocatalyst for the deracemization of racemic 2-methyl-1,2,3,4-tetrahdroquinoline derivatives to yield the unreacted R enantiomer with up to >99 % ee. Sequence alignment revealed that MAO5 shared 14.7 % identity toward the well-studied monoamine oxidase (MAO-N).
- Deng, Guozhong,Wan, Nanwei,Qin, Lei,Cui, Baodong,An, Miao,Han, Wenyong,Chen, Yongzheng
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p. 2374 - 2377
(2018/04/19)
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- Synthesis of Polysubstituted Quinolines from α-2-Aminoaryl Alcohols Via Nickel-Catalyzed Dehydrogenative Coupling
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This study reports a nickel-catalyzed sustainable synthesis of polysubstituted quinolines from α-2-aminoaryl alcohols by a sequential dehydrogenation and condensation process that offers the advantages of a low catalyst loading and wide substrate scope. In contrast to earlier reported methods, this strategy allows the use of both primary as well as secondary α-2-aminoaryl alcohols in combination with either ketones or secondary alcohols for desired product formation. Using this methodology, 30 substituted quinoline derivatives were synthesized with up to 93% isolated yields.
- Das, Sanju,Maiti, Debabrata,De Sarkar, Suman
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p. 2309 - 2316
(2018/02/23)
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- 2 - (b benzene phosphine base ethyl) - (5, 6, 7, 8 - tetrahydro quinolyl) amine ruthenium complex preparation method and application thereof
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The invention discloses a preparation method and application of 2-(diphenylphosphineethyl)-(5,6,7,8-tetrahydroquinolinyl)amine ruthenium complexes. A ligand 2-(diphenylphosphineethyl)-(5,6,7,8-tetrahydroquinolinyl)amine is firstly prepared, and then reacted with RuHCl(CO)(PPh3)3 and RuCl2(PPh3)3 for preparing a complex 1 and a complex 2 which are different in structure, and then the 2-(diphenylphosphineethyl)-(5,6,7,8-tetrahydroquinolinyl)amine ruthenium complex 1 or complex 2 is used to catalyze a condensation reaction of an amino alcohol and a secondary alcohol or a ketone, so that pyridine and quinoline derivatives are synthesized. The preparation method is simple, good in stability, and the catalyst is high in catalytic activity and has the usage amount only being 0.025% by molar of a substrate. The preparation method is applied to production of pyridine and quinoline derivatives, the method is simple, environmental pollution is small, the yield is high and the cost is low.
- -
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Paragraph 0055; 0056; 0057; 0058; 0059
(2017/06/19)
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- Coupling Radical Homoallylic Expansions with C-C Fragmentations for the Synthesis of Heteroaromatics: Quinolines from Reactions of o-Alkenylarylisonitriles with Aryl, Alkyl, and Perfluoroalkyl Radicals
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Selective addition of radicals to isonitriles can be harnessed for initiating reaction cascades designed to overcome the stereoelectronic restrictions on homoallylic ring expansion in alkyne reactions and to develop a new general route for the preparation of N-heteroaromatics. This method utilizes alkenes as synthetic equivalents of alkynes by coupling homoallylic ring expansion to yield the formal "6-endo" products with aromatization via stereoelectronically assisted C-C bond scission. Computational analysis of the homoallyic expansion potential energy surface reveals that the indirect 5-exo/3-exo/retro-3-exo path is faster than the direct 6-endo-trig closure, revealing the general exo-preference for the cyclization processes.
- Evoniuk, Christopher J.,Gomes, Gabriel Dos Passos,Ly, Michelle,White, Frankie D.,Alabugin, Igor V.
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p. 4265 - 4278
(2017/04/27)
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- Bio-mediated oxidative resolution of racemic 2-substituted 1,2,3,4-tetrahydroquinolines
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Whole cell of Pseudomonas monteilii ZMU-T01 strains mediated oxidative resolution of racemic 2-substituted 1,2,3,4-tetrahydroquinolines has been successfully described. A series of highly enantioselective 2-substituted 1,2,3,4-tetrahydroquinoline derivatives were obtained in up to 50% conversion and >99% ee.
- Qin, Lei,Zheng, Daijun,Cui, Baodong,Wan, Nanwei,Zhou, Xiaojian,Chen, Yongzheng
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supporting information
p. 2403 - 2405
(2016/05/19)
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- A Ruthenium Catalyst with Unprecedented Effectiveness for the Coupling Cyclization of - Amino Alcohols and Secondary Alcohols
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The ruthenium complex (8-(2-diphenylphosphinoethyl)aminotrihydroquinolinyl)(carbonyl)(hydrido)ruthenium chloride exhibited extremely high efficiency toward the coupling cyclization of -amino alcohols with secondary alcohols. The corresponding products, pyridine or quinoline derivatives, are obtained in good to high isolated yields. On comparison with literature catalysts whose noble-metal loading with respect to -amino alcohols reached 0.5-1.0 mol % for Ru and a record lowest of 0.04 mol % for Ir, the current catalyst achieves the same efficiency with a loading of 0.025 mol % for Ru. The mechanism of acceptorless dehydrogenative condensation (ADC) was proposed on the basis of DFT calculations; in addition, the reactive intermediates were determined by GC-MS, NMR, and single-crystal X-ray diffraction. The catalytic process is potentially suitable for industrial applications.
- Pan, Bing,Liu, Bo,Yue, Erlin,Liu, Qingbin,Yang, Xinzheng,Wang, Zheng,Sun, Wen-Hua
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p. 1247 - 1253
(2016/02/18)
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- Coupling cyclizations with fragmentations for the preparation of heteroaromatics: Quinolines from o-alkenyl arylisocyanides and boronic acids
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Stereoelectronic restrictions on homoallylic ring expansion in alkyne cascades can be overcome by using alkenes as synthetic equivalents of alkynes in reaction cascades that are terminated by C-C bond fragmentation. Implementation of this approach using Mn(iii)-mediated reaction of o-alkenyl isocyanides and boronic acids leads to efficient synthesis of substituted quinolines.
- Evoniuk, Christopher J.,Ly, Michelle,Alabugin, Igor V.
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supporting information
p. 12831 - 12834
(2015/08/06)
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- A general method for N-methylation of amines and nitro compounds with dimethylsulfoxide
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DMSO methylates a broad range of amines in the presence of formic acid, providing a novel, green and practical method for amine methylation. The protocol also allows the one-pot transformation of aromatic nitro compounds into dimethylated amines in the presence of a simple iron catalyst. Not just a solvent: DMSO methylates a broad range of amines in the presence of formic acid, providing a novel, green and practical method for amine methylation. The protocol also allows the one-pot transformation of aromatic nitro compounds into dimethylated amines in the presence of a simple iron catalyst. Copyright
- Jiang, Xue,Wang, Chao,Wei, Yawen,Xue, Dong,Liu, Zhaotie,Xiao, Jianliang
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supporting information
p. 58 - 63
(2014/01/17)
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- Lithium tert-butoxide mediated α-alkylation of ketones with primary alcohols under transition-metal-free conditions
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LiOtBu was found to efficiently promote the α-alkylation reaction of ketones with primary alcohols, without the addition of any transition metal catalyst.
- Liang, Yu-Feng,Zhou, Xin-Feng,Tang, Shi-Ya,Huang, Yao-Bing,Feng, Yi-Si,Xu, Hua-Jian
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p. 7739 - 7742
(2013/06/27)
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- Alkene isomerization/enamide-ene and diene metathesis for the construction of indoles, quinolines, benzofurans and chromenes with a chiral cyclopropane substituent
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A synthetic method for bicyclic heterocycles, such as indole, benzofuran and chromene derivatives bearing a chiral cyclopropane at the 2-position, was established using isomerization of a terminal olefin and enamide-ene or diene metathesis. This route can also be applied to chiral 2-cyclopropylquinoline synthesis (both cis and trans).
- Kobayashi, Takaaki,Arisawa, Mitsuhiro,Shuto, Satoshi
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p. 1219 - 1224
(2011/04/15)
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- Palladium-catalyzed coupling of N-heteroaryl sulfides with organozinc reagents
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The palladium-catalyzed cross-coupling of N-heteroaryl sulfides with organozinc reagents was developed. Scope and limitation of the reaction regarding generality of zinc reagents and substrate were also investigated.
- Koshiba, Takahiro,Miyazaki, Tohru,Tokuyama, Hidetoshi,Fukuyama, Tohru
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experimental part
p. 233 - 239
(2009/09/06)
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- Rh(I)-catalyzed alkylation of quinolines and pyridines via C-H bond activation
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The scope of heterocycle ortho-alkylation has been dramatically expanded to include pharmaceutically important pyridines and quinolines, which contain only a single nitrogen. The reactions, which are conducted at a high concentration (0.8 M), can be performed with catalyst loadings as low as 1% Rh. Substitution ortho to the heterocycle ring nitrogen is required for efficient alkylation and is consistent with the intermediacy of a Rh-carbene intermediate similar to those proposed in our earlier work. Copyright
- Lewis, Jared C.,Bergman, Robert G.,Ellman, Jonathan A.
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p. 5332 - 5333
(2008/02/04)
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- Synthesis of quinolines from amino alcohol and ketones catalyzed by [IrCl(cod)]2 or IrCl3 under solvent-free conditions
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2-Aminobenzyl alcohol reacted with 2 equiv amount of ketones under the influence of [IrCl(cod)]2 or IrCl3 and KOH without any solvent, giving the corresponding quinoline derivatives in good yields.
- Taguchi, Kazuhiko,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 4539 - 4542
(2007/10/03)
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- Concerning the mechanism of the Friedlaender quinoline synthesis
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Detailed experiments regarding the mechanism of the Friedlaender synthesis of quinolines from o-amino-benzaldehydes and simple aldehydes or ketones are described. Under the basic or acidic conditions commonly used in this reaction, it is concluded that the first step involves a slow intermolecular aldol condensation of the aldehyde or ketone with the o-aminobenzaldehyde. The aldol adduct 5 generated in this manner then undergoes very rapid cyclization to 4, which subsequently loses water to produce the quinoline derivative 8. Both 5 and 4 are too short lived to be detectable (TLC), even when deliberately generated by other means. It is also shown that E-enones corresponding to 6, i.e., the aldol dehydration product, are converted into quinolines (e.g., 21a and 21b from 17a and 17b) under basic or acidic conditions. Such enones are not detected as intermediates in the base-induced Friedlaender synthesis, even though certain congeners (17b) would be easily observable. Under acidic conditions these enones are too short lived to be detectable. Schiff bases derived from 2-aminobenzaldehyde (18a) and aldehydes or ketones can be generated under special conditions, but they show reactivity patterns different from those seen in the usual Friedlaender condensations. Thus, the ytterbium-triflate-catalyzed reaction of aldehydes with 18a at room temperature in toluene generates the E-Schiff bases (33, R1 = H), from which isomeric mixtures of tetrahydroquinoline derivatives 26 are formed exclusively. At higher temperatures, the E-Schiff bases 33 are isomerized to the Z-Schiff bases 34, from which the 3-substituted quinoline derivatives 24 are formed as the major products under appropriate conditions. Also, the ytterbium-triflate-catalyzed reaction of 18a with the pyrrolidine enamines of the methyl-n-alkylketones 38a,b produces mixtures in which the 2-monosubstituted kinetic products 37b,d predominate over the 2,3-disubstituted thermodynamic products 21c,e by a factor of 4:1 to 5:1. These results are opposite to those observed under the usual basic or acidic Friedlaender reactions with methyl-n-alkylketones, where the thermodynamic products are usually strongly favored. The unusual kinetic:thermodynamic product ratios observed with 38a,b are ascribed to the generation and rapid cyclization of mixtures of the Schiff bases 35 and 36, in which the kinetic isomer 35 is highly predominant.
- Muchowski, Joseph M.,Maddox, Michael L.
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p. 461 - 478
(2007/10/03)
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- Homolytic alkylation of heteroaromatic bases : The problem of monoalkylation
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The silver-catalyzed decarboxylation of carboxylic acids by persulphate leads to alkyl radicals, which have been utilized for the selective alkylation of heteroaromatic bases. The method is particularly efficient in a water-chlorobenzene two-phase system for two reasons : it considerably increases the selectivity in monoalkylation when more positions of high nucleophilic reactivity (i.e. α and γ) are available in the heterocyclic ring (i.e. quinoline , 4-cyano- and 4-ethylpyridine, pyrazine , quinoxaline etc.) and it determines a much higher efficiency for the radical sources when the silver salt catalysis is deactivated by complexation of the salt with the heterocyclic compound . The high selectivity in monoalkylation has been obtained by the combination of polar effects and the increased lipophilicity of the alkylated product, which makes its extraction from the aqueous solution by the organic solvent easier.
- Fontana,Minisci,Barbosa, M. C. Nogueira,Vismara
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p. 2525 - 2538
(2007/10/02)
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- Palladium-Mediated Transformations of Heteroaromatic Triflates
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Quinolyl triflates and isoquinolyl triflates undergo palladium-catalysed couplings with organostannanes, organoaluminiums and activated alkenes.The range of organic groups which can be transferred to the heteroaromatic substrate includes aryl, vinyl, alkynyl, alkyl and hydride.
- Crisp, Geoffrey T.,Papadopoulos, Spiros
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p. 279 - 285
(2007/10/02)
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