- Homogeneous pressure hydrogenation of quinolines effected by a bench-stable tungsten-based pre-catalyst
-
We report on an operationally simple catalytic method for the tungsten-catalyzed hydrogenation of quinolines through the use of the easily handled and self-contained precursor [WCl(η5-Cp)(CO)3]. This half sandwich complex is indefinitely storable on the bench in simple screw-capped bottles or stoppered flasks and can, if required, be prepared on a multi-gram scale while the actual catalytic transformations were performed in the presence of a Lewis acid in order to achieve both decent substrate conversions and product yields. The described method represents a facile and atom-efficient access to a variety of 1,2,3,4-tetrahydroquinolines that circumvents the use of cost-intensive and oxygen-sensitive phosphine ligands as well as auxiliary hydride reagents.
- Heizinger, Christian,Topf, Christoph,Vielhaber, Thomas
-
p. 451 - 461
(2021/11/11)
-
- Heterogeneous Hydrogenation of Quinoline Derivatives Effected by a Granular Cobalt Catalyst
-
We communicate a convenient method for the pressure hydrogenation of quinolines in aqueous solution by using a particulate cobalt-based catalyst that is prepared in situ from simple Co(OAc)2 4H2O through reduction with abundant zinc powder. This catalytic protocol permits a brisk and atom-efficient access to a variety of 1,2,3,4-tetrahydroquinolines thereby relying solely on easy-to-handle reagents that are all readily obtained from commercial sources. Both the reaction setup assembly and the autoclave charging procedure are conducted on the bench outside an inert-gas-operated containment system, thus rendering the overall synthesis time-saving and operationally very simple.
- Timelthaler, Daniel,Topf, Christoph
-
-
- Tuning the Catalytic Performance of Cobalt Nanoparticles by Tungsten Doping for Efficient and Selective Hydrogenation of Quinolines under Mild Conditions
-
Non-noble bimetallic CoW nanoparticles (NPs) partially embedded in a carbon matrix (CoW@C) have been prepared by a facile hydrothermal carbon-coating methodology followed by pyrolysis under an inert atmosphere. The bimetallic NPs, constituted by a multishell core-shell structure with a metallic Co core, a W-enriched shell involving Co7W6 alloyed structures, and small WO3 patches partially covering the surface of these NPs, have been established as excellent catalysts for the selective hydrogenation of quinolines to their corresponding 1,2,3,4-tetrahydroquinolines under mild conditions of pressure and temperature. It has been found that this bimetallic catalyst displays superior catalytic performance toward the formation of the target products than the monometallic Co@C, which can be attributed to the presence of the CoW alloyed structures.
- Concepción, Patricia,Corma, Avelino,Liu, Lichen,Puche, Marta,Sorribes, Iván
-
p. 8197 - 8210
(2021/07/13)
-
- Reductive Alkylation of Quinolines to N-Alkyl Tetrahydroquinolines Catalyzed by Arylboronic Acid
-
A boronic acid catalyzed one-pot tandem reduction of quinolines to tetrahydroquinolines followed by reductive alkylation by the aldehyde has been demonstrated. This step-economcial synthesis of N-alkyl tetrahydroquinolines has been achieved directly from readily available quinolines, aldehydes, and Hantzsch ester under mild reaction conditions. The mechanistic study demonstrates the unique behavior of organoboron catalysts as both Lewis acids and hydrogen-bond donors.
- Adhikari, Priyanka,Bhattacharyya, Dipanjan,Nandi, Sekhar,Kancharla, Pavan K.,Das, Animesh
-
supporting information
p. 2437 - 2442
(2021/04/05)
-
- A General Catalyst Based on Cobalt Core–Shell Nanoparticles for the Hydrogenation of N-Heteroarenes Including Pyridines
-
Herein, we report the synthesis of specific silica-supported Co/Co3O4 core–shell based nanoparticles prepared by template synthesis of cobalt-pyromellitic acid on silica and subsequent pyrolysis. The optimal catalyst material allows for general and selective hydrogenation of pyridines, quinolines, and other heteroarenes including acridine, phenanthroline, naphthyridine, quinoxaline, imidazo[1,2-a]pyridine, and indole under comparably mild reaction conditions. In addition, recycling of these Co nanoparticles and their ability for dehydrogenation catalysis are showcased.
- Beller, Matthias,Chandrashekhar, Vishwas G.,Jagadeesh, Rajenahally V.,Kreyenschulte, Carsten,Murugesan, Kathiravan
-
supporting information
p. 17408 - 17412
(2020/08/21)
-
- Boric acid catalyzed chemoselective reduction of quinolines
-
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
-
supporting information
p. 1214 - 1220
(2020/02/22)
-
- The Alkylation and Reduction of Heteroarenes with Alcohols Using Photoredox Catalyzed Hydrogen Atom Transfer via Chlorine Atom Generation
-
Radical additions to heteroaromatic bases are frequently employed for the rapid synthesis of complex products using C–H functionalization strategies. The conditions that are commonly employed are typically harsh, routinely requiring stoichiometric oxidants and other additives. In search for milder reaction environments allowing late-stage functionalization, we present the alkylation of N-heteroarenes using primary alcohols and ethers as radical precursors, where the corresponding alkyl radical is formed via hydrogen atom transfer process with a photoredox catalyzed chlorine atom generation as HAT agent. Furthermore, we explore the reduction of the heteroarenes in moderate to high yields when using secondary alcohols.
- Zidan, Montserrat,Morris, Avery O.,McCallum, Terry,Barriault, Louis
-
supporting information
p. 1453 - 1458
(2019/08/01)
-
- Half-Sandwich Ruthenium Complexes for One-Pot Synthesis of Quinolines and Tetrahydroquinolines: Diverse Catalytic Activity in the Coupled Cyclization and Hydrogenation Process
-
Four types of half-sandwich ruthenium complexes with an N,O-coordinate mode based on hydroxyindanone-imine ligands have been prepared in good yields. These stable ruthenium complexes exhibited high activity in the catalytic synthesis of quinolines from the reactions of amino alcohols with different types of ketones or secondary alcohols under very mild conditions. Moreover, the methodology for the direct one-pot synthesis of tetrahydroquinoline derivatives from amino alcohols and ketones has been also developed on the basis of the continuous catalytic activity of this ruthenium catalyst in the selective hydrogenation of the obtained quinoline derivatives with a low catalyst loading. The corresponding products, quinolines and tetrahydroquinoline derivatives, were afforded in good to excellent yields. The efficient and diverse catalytic activity of these ruthenium complexes suggested their potential large-scale application. All of the ruthenium complexes were characterized by various spectroscopies to confirm their structures.
- Yun, Xue-Jing,Zhu, Jing-Wei,Jin, Yan,Deng, Wei,Yao, Zi-Jian
-
supporting information
p. 7841 - 7851
(2020/06/04)
-
- Homogeneous Hydrogenation with a Cobalt/Tetraphosphine Catalyst: A Superior Hydride Donor for Polar Double Bonds and N-Heteroarenes
-
The development of catalysts based on earth abundant metals in place of noble metals is becoming a central topic of catalysis. We herein report a cobalt/tetraphosphine complex-catalyzed homogeneous hydrogenation of polar unsaturated compounds using an air- and moisture-stable and scalable precatalyst. By activation with potassium hydroxide, this cobalt system shows both high efficiency (up to 24 000 TON and 12 000 h-1 TOF) and excellent chemoselectivities with various aldehydes, ketones, imines, and even N-heteroarenes. The preference for 1,2-reduction over 1,4-reduction makes this method an efficient way to prepare allylic alcohols and amines. Meanwhile, efficient hydrogenation of the challenging N-heteroarenes is also furnished with excellent functional group tolerance. Mechanistic studies and control experiments demonstrated that a CoIH complex functions as a strong hydride donor in the catalytic cycle. Each cobalt intermediate on the catalytic cycle was characterized, and a plausible outer-sphere mechanism was proposed. Noteworthy, external inorganic base plays multiple roles in this reaction and functions in almost every step of the catalytic cycle.
- Duan, Ya-Nan,Du, Xiaoyong,Cui, Zhikai,Zeng, Yiqun,Liu, Yufeng,Yang, Tilong,Wen, Jialin,Zhang, Xumu
-
supporting information
p. 20424 - 20433
(2019/12/27)
-
- General and Chemoselective Copper Oxide Catalysts for Hydrogenation Reactions
-
Copper oxide catalysts have been prepared by pyrolysis of copper acetate on aluminum oxide. The material resulting from pyrolysis at 800 °C allows for catalytic hydrogenations at low temperature of a variety of unsaturated compounds such as quinolines, alkynes, ketones, imines, and polycyclic aromatic hydrocarbons as well as nitroarenes with good activity and selectivity.
- Li, Wu,Cui, Xinjiang,Junge, Kathrin,Surkus, Annette-Enrica,Kreyenschulte, Carsten,Bartling, Stephan,Beller, Matthias
-
p. 4302 - 4307
(2019/05/08)
-
- Activation of Quinolines by Cationic Chalcogen Bond Donors
-
The application of already established as well as novel selenium- and sulfur-based cationic chalcogen bond donors in the catalytic activation of quinoline derivatives is presented. In the presence of selected catalysts, rate accelerations of up to 2300 compared to virtually inactive reference compounds are observed. The catalyst loading can be reduced to 1 molpercent while still achieving nearly full conversion for electron-poor and electron-rich quinolines. Contrary to expectations, preorganized catalysts were less active than the more flexible variants.
- Huber, S. M.,Steinke, T.,Wonner, P.
-
supporting information
p. 1673 - 1678
(2019/08/26)
-
- A robust iron catalyst for the selective hydrogenation of substituted (iso)quinolones
-
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
-
p. 8134 - 8141
(2018/11/20)
-
- Nanolayered Cobalt-Molybdenum Sulfides as Highly Chemo- and Regioselective Catalysts for the Hydrogenation of Quinoline Derivatives
-
Herein, a general protocol for the preparation of a broad range of valuable N-heterocyclic products by hydrogenation of quinolines and related N-heteroarenes is described. Interestingly, the catalytic hydrogenation of the N-heteroarene ring is chemoselectively performed when other facile reducible functional groups, including alkenes, ketones, cyanides, carboxylic acids, esters, and amides, are present. The key to successful catalysis relies on the use of a nanolayered cobalt-molybdenum sulfide catalyst hydrothermally synthesized from earth-abundant metal precursors. This heterogeneous system displays a tunable composition of phases that allows for catalyst regeneration. Its catalytic activity depends on the composition of the mixed phase of cobalt sulfides, being higher with the presence of Co3S4, and could also be associated with the presence of transient Co-Mo-S structures that mainly vanish after the first catalytic run.
- Sorribes, Iván,Liu, Lichen,Doménech-Carbó, Antonio,Corma, Avelino
-
p. 4545 - 4557
(2018/05/22)
-
- STABILIZATION OF ACTIVE METAL CATALYSTS AT METAL-ORGANIC FRAMEWORK NODES FOR HIGHLY EFFICIENT ORGANIC TRANSFORMATIONS
-
Metal-organic framework (MOFs) compositions based on post?synthetic metalation of secondary building unit (SBU) terminal or bridging OH or OH2 groups with metal precursors or other post-synthetic manipulations are described. The MOFs provide a versatile family of recyclable and reusable single-site solid catalysts for catalyzing a variety of asymmetric organic transformations, including the regioselective boryiation and siiylation of benzyiic C—H bonds, the hydrogenation of aikenes, imines, carbonyls, nitroarenes, and heterocycles, hydroboration, hydrophosphination, and cyclization reactions. The solid catalysts can also be integrated into a flow reactor or a supercritical fluid reactor.
- -
-
Paragraph 0349
(2019/01/07)
-
- Iodine catalyzed reduction of quinolines under mild reaction conditions
-
A reduction of quinolines to synthetically versatile tetrahydroquinoline molecules with I2 and HBpin is described. In the presence of iodine (20 mol%) as a catalyst, reduction of quinolines and other N-heteroarenes proceeded readily with hydroboranes as the reducing reagents. The broad functional-group tolerance, good yields and mild reaction conditions imply high practical utility.
- Yang, Chun-Hua,Chen, Xixi,Li, Huimin,Wei, Wenbo,Yang, Zhantao,Chang, Junbiao
-
supporting information
p. 8622 - 8625
(2018/08/06)
-
- Cyclopentadiene-based Br?nsted acid as a new generation of organocatalyst for transfer hydrogenation of 2-substituted quinoline derivatives
-
A simple and readily available cyclopentadiene-based Br?nsted acid was employed to catalyze the transfer hydrogenation of 2-substituted quinolines using Hantzsch ester as the hydrogen source. This conceptually new designed organocatalyst demonstrates remarkably high efficiency for this transformation and a variety of substituted 1,2,3,4-tetrahydroquinoline derivatives were afforded in excellent yields under mild reaction conditions.
- Qiao, Xiang,El-Shahat, Mahmoud,Ullah, Bakhtar,Bao, Zongbi,Xing, Huabin,Xiao, Li,Ren, Qilong,Zhang, Zhiguo
-
supporting information
p. 2050 - 2053
(2017/05/04)
-
- Structure-Activity Relationship Studies with Tetrahydroquinoline Analogs as EPAC Inhibitors
-
EPAC proteins are therapeutic targets for the potential treatment of cardiac hypertrophy and cancer metastasis. Several laboratories use a tetrahydroquinoline analog, CE3F4, to dissect the role of EPAC1 in various disease states. Here, we report SAR studies with tetrahydroquinoline analogs that explore various functional groups. The most potent EPAC inhibitor 12a exists as a mixture of inseparable E (major) and Z (minor) rotamers. The rotation about the N-formyl group indeed impacts the activity against EPAC.
- Sonawane, Yogesh A.,Zhu, Yingmin,Garrison, Jered C.,Ezell, Edward L.,Zahid, Muhammad,Cheng, Xiaodong,Natarajan, Amarnath
-
supporting information
p. 1183 - 1187
(2017/11/15)
-
- A General and Highly Selective Cobalt-Catalyzed Hydrogenation of N-Heteroarenes under Mild Reaction Conditions
-
Herein, a general and efficient method for the homogeneous cobalt-catalyzed hydrogenation of N-heterocycles, under mild reaction conditions, is reported. Key to success is the use of the tetradentate ligand tris(2-(diphenylphosphino)phenyl)phosphine). This non-noble metal catalyst system allows the selective hydrogenation of heteroarenes in the presence of a broad range of other sensitive reducible groups.
- Adam, Rosa,Cabrero-Antonino, Jose R.,Spannenberg, Anke,Junge, Kathrin,Jackstell, Ralf,Beller, Matthias
-
supporting information
p. 3216 - 3220
(2017/03/17)
-
- Catalysis with Chalcogen Bonds
-
Herein, we introduce catalysts that operate with chalcogen bonds. Compared to conventional hydrogen bonds, chalcogen bonds are similar in strength but more directional and hydrophobic, thus ideal for precision catalysis in apolar solvents. For the transfer hydrogenation of quinolines and imines, rate enhancements well beyond a factor of 1000 are obtained with chalcogen bonds. Better activities with deeper σ holes and wider bite angles, chloride inhibition and correlation with computed anion binding energies are consistent with operational chalcogen bonds. Comparable to classics, such as 2,2′-bipyrroles or 2,2′-bipyridines, dithieno[3,2-b;2′,3′-d]thiophenes (DTTs), particularly their diimides, but also wide-angle cyclopentadithiazole-4-ones are identified as privileged motifs to stabilize transition states in the focal point of the σ holes on their two co-facial endocyclic sulfur atoms.
- Benz, Sebastian,López-Andarias, Javier,Mareda, Jiri,Sakai, Naomi,Matile, Stefan
-
supporting information
p. 812 - 815
(2017/01/14)
-
- Catalysis with chalcogen bonds: Neutral benzodiselenazole scaffolds with high-precision selenium donors of variable strength
-
The benzodiselenazoles (BDS) introduced in this report fulfill, for the first time, all the prerequisites for non-covalent high-precision chalcogen-bonding catalysis in the focal point of conformationally immobilized σ holes on strong selenium donors in a neutral scaffold. Rational bite-angle adjustment to the long Se-C bonds was the key for BDS design. For the unprecedented BDS motif, synthesis of 12 analogs from o-xylene, crystal structure, σ hole variation strategies, optoelectronic properties, theoretical and experimental anion binding as well as catalytic activity are reported. Chloride binding increases with the depth of the σ holes down to KD = 11 μM in THF. Catalytic activities follow the same trend and culminate in rate enhancements for transfer hydrogenation of quinolines beyond 100000.
- Benz, Sebastian,Mareda, Jiri,Besnard, Céline,Sakai, Naomi,Matile, Stefan
-
p. 8164 - 8169
(2017/11/27)
-
- A Rhodium Nanoparticle-Lewis Acidic Ionic Liquid Catalyst for the Chemoselective Reduction of Heteroarenes
-
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.
-
supporting information
p. 292 - 296
(2016/01/25)
-
- Single-Site Cobalt Catalysts at New Zr8(μ2-O)8(μ2-OH)4 Metal-Organic Framework Nodes for Highly Active Hydrogenation of Alkenes, Imines, Carbonyls, and Heterocycles
-
We report here the synthesis of robust and porous metal-organic frameworks (MOFs), M-MTBC (M = Zr or Hf), constructed from the tetrahedral linker methane-tetrakis(p-biphenylcarboxylate) (MTBC) and two types of secondary building units (SBUs): cubic M8(μ2-O)8(μ2-OH)4 and octahedral M6(μ3-O)4(μ3-OH)4. While the M6-SBU is isostructural with the 12-connected octahedral SBUs of UiO-type MOFs, the M8-SBU is composed of eight MIV ions in a cubic fashion linked by eight μ2-oxo and four μ2-OH groups. The metalation of Zr-MTBC SBUs with CoCl2, followed by treatment with NaBEt3H, afforded highly active and reusable solid Zr-MTBC-CoH catalysts for the hydrogenation of alkenes, imines, carbonyls, and heterocycles. Zr-MTBC-CoH was impressively tolerant of a range of functional groups and displayed high activity in the hydrogenation of tri- and tetra-substituted alkenes with TON > 8000 for the hydrogenation of 2,3-dimethyl-2-butene. Our structural and spectroscopic studies show that site isolation of and open environments around the cobalt-hydride catalytic species at Zr8-SBUs are responsible for high catalytic activity in the hydrogenation of a wide range of challenging substrates. MOFs thus provide a novel platform for discovering and studying new single-site base-metal solid catalysts with enormous potential for sustainable chemical synthesis.
- Ji, Pengfei,Manna, Kuntal,Lin, Zekai,Urban, Ania,Greene, Francis X.,Lan, Guangxu,Lin, Wenbin
-
supporting information
p. 12234 - 12242
(2016/09/28)
-
- A simple iridicycle catalyst for efficient transfer hydrogenation of n-heterocycles in water
-
A cyclometalated iridium complex is shown to catalyse the transfer hydrogenation of various nitrogen heterocycles, including but not limited to quinolines, isoquinolines, indoles and pyridinium salts, in an aqueous solution of HCO2H/HCO2Na under mild conditions. The catalyst shows excellent functional-group compatibility and high turnover number (up to 7500), with catalyst loadings as low as 0.01 mol % being feasible. Mechanistic investigation of the quinoline reduction suggests that the transfer hydrogenation proceeds via both 1,2- and 1,4-addition pathways, with the catalytic turnover being limited by the step of hydride transfer. An easily accessible iridicycle catalyst effects the transfer hydrogenation of a wide variety of N-heterocycles in water, including quinolines, isoquinolines, indoles, quinoxalines, and pyridines. The catalyst shows excellent functional-group compatibility and high turnover number (up to 7500), even with low catalyst loadings.
- Talwar, Dinesh,Li, Ho Yin,Durham, Emma,Xiao, Jianliang
-
supporting information
p. 5370 - 5379
(2015/03/30)
-
- Selective Catalytic Hydrogenation of Heteroarenes with N-Graphene-Modified Cobalt Nanoparticles (Co3O4-Co/NGratα-Al2O3)
-
Cobalt oxide/cobalt-based nanoparticles featuring a core-shell structure and nitrogen-doped graphene layers on alumina are obtained by pyrolysis of Co(OAc)2/phenanthroline. The resulting core-shell material (Co3O4-Co/NGratα-Al2O3) was successfully applied in the catalytic hydrogenation of a variety of N-heteroarenes including quinolines, acridines, benzo[h], and 1,5-naphthyridine as well as unprotected indoles. The peculiar structure of the novel heterogeneous catalyst enables activation of molecular hydrogen at comparably low temperature. Both high activity and selectivity were achieved in these hydrogenation processes, to give important building blocks for bioactive compounds as well as the pharmaceutical industry.
- Chen, Feng,Surkus, Annette-Enrica,He, Lin,Pohl, Marga-Martina,Radnik, J?rg,Topf, Christoph,Junge, Kathrin,Beller, Matthias
-
supporting information
p. 11718 - 11724
(2015/09/28)
-
- Reduction of quinolines to 1,2,3,4-tetrahydroquinolines with hydrosilane/ethanol catalyzed by TiO2-supported gold nanoparticles under solvent free conditions
-
Gold nanoparticles supported on TiO2 (1 mol%) catalyze the reduction of a series of functionalized quinolines into 1,2,3,4-tetrahydroquinolines using hydrosilanes/ethanol (hydride/proton) as the reductant system. A typical reaction requires 4 molar equivalents of phenyldimethylsilane (reductant of choice), 4 molar equivalents of ethanol as a reagent and heating to 70 °C under solvent free conditions. The isolated yields are moderate to excellent and in certain cases the reaction rate is exceedingly fast. Mechanistic analysis revealed the stereoselective addition of two hydrides (from hydrosilane) on positions C2 and C4 of the quinoline ring and two protons (from ethanol) on positions C3 and the nitrogen atom.
- Louka, Anastasia,Gryparis, Charis,Stratakis, Manolis
-
-
- A comparative study on the acylative kinetic resolution of racemic fluorinated and non-fluorinated 2-methyl-1,2,3,4-tetrahydroquinolines and 3,4-dihydro-3-methyl-2H-[1,4]benzoxazines
-
The acylative kinetic resolution of racemic 6-fluoro-2-methyl-1,2,3,4- tetrahydroquinoline, 7,8-difluoro-3,4-dihydro-3-methyl-2H-[1,4]benzoxazine, and their non-fluorinated analogues with (S)-naproxen and N-phthaloyl-(S)-amino acyl chlorides has been carried out. It has been shown that the presence of fluorine atoms in the aromatic fragment of a heterocyclic amine results in the increasing stereoselectivity of acylation with (S)-naproxen acyl chloride and in a decrease in the efficiency of acylative kinetic resolution using N-phthaloyl-(S)-amino acyl chlorides. A method for the preparation of enantiopure (S)-6-fluoro-2-methyl-1,2,3,4-tetrahydroquinoline (ee >99%) was developed.
- Gruzdev, Dmitry A.,Chulakov, Evgeny N.,Levit, Galina L.,Ezhikova, Marina A.,Kodess, Mikhail I.,Krasnov, Victor P.
-
p. 1240 - 1246
(2013/10/22)
-
- The remarkable effect of a simple ion: Iodide-promoted transfer hydrogenation of heteroaromatics
-
I can do it! Accelerated by simple iodide ions, rhodium-catalysed transfer hydrogenation can be readily performed on quinolines, isoquinolines and quinoxalines, affording the tetrahydro products in high yields with low catalyst loading (see scheme). Copyright
- Wu, Jianjun,Wang, Chao,Tang, Weijun,Pettman, Alan,Xiao, Jianliang
-
supporting information; experimental part
p. 9525 - 9529
(2012/08/28)
-
- Method of making and administering quinoline derivatives as anti-cancer agents
-
The present invention relates methods of preparing quinoline derivative compounds, and administering such compounds in the treatment of solid and non-solid tumors, notably on liver cancer.
- -
-
-
- Organocatalysis through halogen-bond activation
-
Haloperfluoroalkanes have been used as catalysts for the reduction of 2-phenylquinoline to its corresponding 1,2,3,4-tetrahydro derivative using a Hantzsch ester as reductand. The results suggest a substrate activation by halogen bonding. Georg Thieme Verlag Stuttgart.
- Bruckmann, Angelika,Pena, Miguel A.,Bolm, Carsten
-
p. 900 - 902
(2008/12/22)
-
- An efficient catalytic system for the hydrogenation of quinolines
-
A new catalytic system ([Ru(p-cymene)Cl2]2/I2) has been developed for the hydrogenation of quinoline derivatives with high reactivity. For the 2-methyl-quinoline, the hydrogenation reaction can proceed smoothly at an S/C of 20,000/1 with complete conversion. The iodine additive is important for the reactivity.
- Lu, Sheng-Mei,Han, Xiu-Wen,Zhou, Yong-Gui
-
p. 3065 - 3069
(2008/02/02)
-
- Metal-free Br?nsted acid catalyzed transfer hydrogenation - New organocatalytic reduction of quinolines
-
The first metal-free Br?nsted acid catalyzed hydrogenation of quinolines using Hantzsch dihydropyridine as the hydrogen source has been developed. This, so far unprecedented organocatalytic reduction of heteroaromatic compounds provides a variety of differently substituted 1,2,3,4-tetrahydroquinolines in excellent yields under mild reaction conditions using a remarkably low amount of Br?nsted acid catalyst. Georg Thieme Verlag Stuttgart.
- Rueping, Magnus,Theissmann, Thomas,Antonchick, Andrey P.
-
p. 1071 - 1074
(2007/10/03)
-
- Process for the preparation of optically active compounds
-
Process for the resolution of 6-fluoro-1,2,3,4-tetrahydro-2-methyl-quinoline using L-(-)-di-para-toluoyl-tartaric acid as resolving agent.
- -
-
-
- Process for 6,7-dihydro-9-fluoro-5-methyl-1-oxo-1H,5H-benzo(ij)quinolizine-2-carboxylic acid
-
An improved process for preparing the antimicrobial compound flumequine is disclosed. The first step of the process comprises reacting 4-fluoroaniline with crotonaldehyde under acidic conditions at a temperature between 50° and 60° C. In the second step, the product of the first step is treated to provide a mixture of 6-fluoroquinaldine and 6-fluorotetrahydroquinaldine. This mixture is then treated with base in the presence of weak acid followed by reducing to provide 6-fluorotetrahydroquinaldine. This compound is then treated according to known procedures to form flumequine.
- -
-
-
- Intermediates for 6,7-dihydro-9-fluoro-5-methyl-1-oxo-1H,5H-benzo(ij)quinolizine-2-carboxylic acid
-
Intermediates in a process for preparing the antimicrobial compound flumequine are disclosed. The intermediates have the following formula STR1 wherein R is hydrogen or alkyl having 1-3 carbon atoms and acid addition salts thereof.
- -
-
-