- Transition metal eight-coordination. IV. Tetrakis(5,7-disubstituted-8-quinolinolato)tungsten(V) salts
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Violet, paramagnetic [WQ4]+ ions have been synthesized by a variety of methods and appear to be the first complexes of tungsten(V) possessing four chelate ligands. The 5,7-dichloro-8-quinolinol derivative has been synthesized by the reaction of either K3W2Cl9 or W(CO)6 with excess ligand at elevated temperatures for extended time periods or by treating the corresponding tungsten(IV) inner complex with Cl2, Br2, or HClO4 at room temperature or with additional ligand at elevated temperatures. The 7-bromo-5-methyl-8-quinolinol-tungsten(V) species is rapidly produced in the melt reaction of the ligand with W(CO)6. The [WQ4]X salts, where X- = Cl-, Br-, ClO4-, or Q-, disproportionate in alcoholic or aqueous KOH to WQ4 and tungsten(VI). Electronic transitions of the [WQ4] species consist of several bands in the near-infrared and visible region in addition to the normal ligand spectral transitions. A magnetic moment of 1.7 BM, a 〈g〉 value of 1.872, and a 183W hyperfine splitting of 85 G were observed for the dichloro derivative at room temperature. Low-temperature electron spin resonance spectra exhibit three anisotropic g values indicative of isomerization from the D2d-mmmm isomer found for a related 5-bromo-8-quinolinol-tungsten(IV) chelate.1a.
- Archer, Ronald D.,Bonds Jr., Wesley D.,Pribush, Robert A.
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- Using Data Science To Guide Aryl Bromide Substrate Scope Analysis in a Ni/Photoredox-Catalyzed Cross-Coupling with Acetals as Alcohol-Derived Radical Sources
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Ni/photoredox catalysis has emerged as a powerful platform for C(sp2)–C(sp3) bond formation. While many of these methods typically employ aryl bromides as the C(sp2) coupling partner, a variety of aliphatic radical sources have been investigated. In principle, these reactions enable access to the same product scaffolds, but it can be hard to discern which method to employ because nonstandardized sets of aryl bromides are used in scope evaluation. Herein, we report a Ni/photoredox-catalyzed (deutero)methylation and alkylation of aryl halides where benzaldehyde di(alkyl) acetals serve as alcohol-derived radical sources. Reaction development, mechanistic studies, and late-stage derivatization of a biologically relevant aryl chloride, fenofibrate, are presented. Then, we describe the integration of data science techniques, including DFT featurization, dimensionality reduction, and hierarchical clustering, to delineate a diverse and succinct collection of aryl bromides that is representative of the chemical space of the substrate class. By superimposing scope examples from published Ni/photoredox methods on this same chemical space, we identify areas of sparse coverage and high versus low average yields, enabling comparisons between prior art and this new method. Additionally, we demonstrate that the systematically selected scope of aryl bromides can be used to quantify population-wide reactivity trends and reveal sources of possible functional group incompatibility with supervised machine learning.
- Doyle, Abigail G.,Gandhi, Shivaani S.,Jiang, Shutian,Kariofillis, Stavros K.,Martinez Alvarado, Jesus I.,?urański, Andrzej M.
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supporting information
p. 1045 - 1055
(2022/01/19)
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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 0046-0048
(2020/11/12)
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- A methylation platform of unconventional inert aryl electrophiles: Trimethylboroxine as a universal methylating reagent
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Methylation is one of the most fundamental conversions in medicinal and material chemistry. Extension of substrate types from aromatic halides to other unconventional aromatic electrophiles is a highly important yet challenging task in catalytic methylation. Disclosed herein is a series of transition metal-catalyzed methylations of unconventional inert aryl electrophiles using trimethylboroxine (TMB) as the methylating reagent. This transformation features a broad substrate type, including nitroarenes, benzoic amides, benzoic esters, aryl cyanides, phenol ethers, aryl pivalates and aryl fluorides. Another important merit of this work is that these widespread "inert"functionalities are capable of serving as directing or activating groups for selective functionalization of aromatic rings before methylation, which greatly expands the connotation of methylation chemistry.
- Feng, Boya,Yang, Yudong,You, Jingsong
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p. 6031 - 6035
(2020/07/10)
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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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- Enantioselective Intermolecular [2 + 2] Photocycloaddition Reactions of 2(1H)-Quinolones Induced by Visible Light Irradiation
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In the presence of a chiral thioxanthone catalyst (10 mol %) the title compounds underwent a clean intermolecular [2 + 2] photocycloaddition with electron-deficient olefins at λ = 419 nm. The reactions not only proceeded with excellent regio- and diastereoselectivity but also delivered the respective cyclobutane products with significant enantiomeric excess (up to 95% ee). Key to the success of the reactions is a two-point hydrogen bonding between quinolone and catalyst enabling efficient energy transfer and high enantioface differentiation. Preliminary work indicated that solar irradiation can be used for this process and that the substrate scope can be further expanded to isoquinolones.
- Tr?ster, Andreas,Alonso, Rafael,Bauer, Andreas,Bach, Thorsten
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supporting information
p. 7808 - 7811
(2016/07/07)
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- Highly Enantioselective Direct Synthesis of Endocyclic Vicinal Diamines through Chiral Ru(diamine)-Catalyzed Hydrogenation of 2,2′-Bisquinoline Derivatives
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An asymmetric hydrogenation of 2,2′-bisquinoline and bisquinoxaline derivatives, catalyzed by chiral cationic ruthenium diamine complexes, was developed. A broad range of chiral endocyclic vicinal diamines were obtained in high yields with excellent diastereo- and enantioselectivity (up to 93:7 dl/meso and >99 % ee). These chiral diamines could be easily transformed into a new class of chiral N-heterocyclic carbenes (NHCs), which are important but difficult to access.
- Ma, Wenpeng,Zhang, Jianwei,Xu, Cong,Chen, Fei,He, Yan-Mei,Fan, Qing-Hua
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supporting information
p. 12891 - 12894
(2016/10/04)
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- Synthesis of quinolines by iron-catalyzed reaction of anilines with propane-1,3-diol
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Quinoline and its derivatives were synthesized by cyclocondensation of anilines with propane-1,3-diol in 57-96% yield in the presence of iron-containing catalysts in carbon tetrachloride.
- Khusnutdinov,Bayguzina,Aminov
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p. 2725 - 2727
(2016/02/18)
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- Copper-Promoted Tandem Reaction of Azobenzenes with Allyl Bromides via N=N Bond Cleavage for the Regioselective Synthesis of Quinolines
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A copper-promoted tandem reaction of a variety of azobenzenes and allyl bromides via N=N bond cleavage to regioselectively construct quinoline derivatives has been developed. The azobenzenes act as not only construction units but also an oxidant for quinoline formation.
- Yi, Xiangli,Xi, Chanjuan
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p. 5836 - 5839
(2015/12/11)
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- Quinoline synthesis by improved Skraup-Doebner-Von Miller reactions utilizing acrolein diethyl acetal
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A robust synthetic method has been developed as an improvement to the venerable Skraup-Doebner-Von Miller reaction providing access to various quinoline products. The straightforward procedure utilizes acrolein diethyl acetal as a three-carbon annulation partner with aniline substrates in a monophasic, organic solvent-free reaction medium. Differentially substituted aniline precursors were found to be compatible with the reaction conditions and the corresponding quinoline products are isolated in moderate to good yields.
- Ramann, Ginelle A.,Cowen, Bryan J.
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supporting information
p. 6436 - 6439
(2015/11/16)
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- Quinoline and phenanthroline preparation starting from glycerol via improved microwave-assisted modified Skraup reaction
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An efficient "green" modified Skraup reaction in neat water was developed using inexpensive, abundant and environmentally-friendly glycerol under microwave irradiation conditions. Starting from aniline derivatives, various quinolines were obtained in 10-66% yields. The use of nitroaniline led to the corresponding phenanthrolines in 15-52% yields, respectively. This journal is the Partner Organisations 2014.
- Saggadi, Hanen,Luart, Denis,Thiebault, Nicolas,Polaert, Isabelle,Estel, Lionel,Len
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p. 21456 - 21464
(2014/06/10)
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- Enantioselective, nickel-catalyzed suzuki cross-coupling of quinolinium ions
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Quinolinium ions are engaged in an asymmetric, Ni-catalyzed Suzuki cross-coupling to yield 2-aryl- and 2-heteroaryl-1,2-dihydroquinolines. Key to the development of this method is the use of a Ni(II) precatalyst that activates without the need for strong reductants or high temperatures. The Ni-iminium activation mode is demonstrated as an exceptionally mild pathway to generate enantioenriched products from racemic starting materials.
- Shields, Jason D.,Ahneman, Derek T.,Graham, Thomas J. A.,Doyle, Abigail G.
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supporting information
p. 142 - 145
(2014/01/23)
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- Reduction of nitroarenes followed by propanol group transfer from tris(3-hydroxypropyl)- amine and cyclization leading to quinolines under heterogeneous Pd-C catalysis
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Nitroarenes having electron-donating or -withdrawing substituents are reduced to anilines and cyclized with tris(3- hydroxypropyl)amine in the presence of a catalytic amount of Pd-C along with tin(II) chloride and isopropanol in dioxane-H2O medium to give the corresponding quinolines in good to excellent yields. Copyright
- Cho, Chan Sik,Kim, Tae Gyun,Yoon, Nam Sik
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experimental part
p. 291 - 293
(2010/08/04)
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- Ruthenium-catalyzed synthesis of quinolines via reductive heteroannulation of nitroarenes with 3-amino-1-propanols
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Nitroarenes are reductively cyclized with 3-amino-1-propanols in dioxane/H2O in the presence of a ruthenium catalyst and tin(II) chloride dihydrate together with isopropanol to afford the corresponding quinolines. A reaction pathway involving i
- Cho, Chan Sik,Kyung Kim, Tae,Kim, Tae-Jeong,Shim, Sang Chul,Yoon, Nam Sik
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p. 291 - 294
(2007/10/03)
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- Synthesis of quinolines by ruthenium-catalyzed heteroannulation of anilines with 3-amino-1-propanol
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Anilines react with 3-amino-1-propanol in dioxane in the presence of a catalytic amount of a ruthenium catalyst and tin(II) chloride dihydrate together with a hydrogen acceptor to afford the corresponding quinolines in moderate yields.
- Cho, Chan Sik,Oh, Byoung Ho,Shim, Sang Chul
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p. 1175 - 1178
(2007/10/03)
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- FORMATION OF INDOLES AND QUINOLINES BY FLASH VACUUM PYROLYSIS
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Flash vacuum pyrolysis of N-(2-methylphenyl)benzimidoyl chlorides and N,N-dimethyl-N'-(2-methylphenyl)formamidines provides a simple route to 2-aryl- and 2-unsubstituted indoles.Pyrolysis of N,N-dimethyl-N-(2-methylphenyl)-acetamidines gives mainly quinolines in a reaction which reveals a novel, high temperature rearrangement of 3,4-dihydroquinolines.
- Randles, K. R.,Storr, R. C.
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p. 5555 - 5558
(2007/10/02)
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- Selectivity of Hydrogenations. Part 4. 6- and 8-Substituted Quinaldines. Yield of Tetrahydroderivatives and Basicities of Quinolines
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Hydrogenation of 6- or 8-R-substituted quinaldines over platinum in trifluoracetic acid gave higher yields (ca.90percent) of 5,6,7,8-tetrahydroderivatives than hydrogenation of the corresponding quinolines.The pKa-values of 20 quinolines and quinaldines were determined by measuring the half-neutralisation potentials in acetic anhydride.More basic quinolines gave higher yields of 5,6,7,8-tetrahydroproduct; exceptions are 6- and 8-methylquinoline and 8-tert. butylquinoline.Explanations for these observations are suggested. - Keywords:Catalytic hydrogenation; PKa-Values; Quinaldines; Quinolines; 5,6,7,8-Tetrahydroquinolines, yields of.
- Hoenel, Michael,Vierhapper, Friedrich W.
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p. 1219 - 1228
(2007/10/02)
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- Thermolysis of Polyazapentadienes. Part 6. Gas-phase Cyclisation of 1,5-Diaryl-1,5-diazapentadienes: Mechanistic Aspects and some Synthetic Applications
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The mode of formation of quinolines by gas-phase pyrolysis of 1,5-diaryl-1,5-diazapentadienes is contrasted with the thermal behaviour of 1,2,5-triazapentadienes.The mechanism involves concerted ring closure followed by a rapid 1,5-hydrogen shift to give a 3,4-dihydroquinoline intermediate, e.g. (19) or (21).Subsequent aromatisation takes place by a stepwise, free-radical process.Methylquinolines (9), (10), (12), and (13) were obtained on a preparative scale by this method.
- McNab, Hamish,Murray, M. Elizabeth-Ann
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p. 1565 - 1568
(2007/10/02)
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- STUDIES ON HISTRIONICOTOXIN: REARRANGEMENT OF THE SPIROCYCLIC HISTRIONICOTOXIN CARBON SKELETON INTO THE FUSED PUMILIOTOXIN SKELETON
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On the treatment with acid the spirocyclic ketoamine 5 undergoes a retro-Mannich reaction followed by recondensation to give the unsaturated imine 8, thus converting the histrionicotoxin carbon skeleton into the pumiliotoxin C skeleton.
- Venit, John J.,Magnus, Philip
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p. 4815 - 4818
(2007/10/02)
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