- Homologation of the Fischer Indolization: A Quinoline Synthesis via Homo-Diaza-Cope Rearrangement
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We disclose a new Br?nsted acid promoted quinoline synthesis, proceeding via homo-diaza-Cope rearrangement of N-aryl-N′-cyclopropyl hydrazines. Our strategy can be considered a homologation of Fischer's classical indole synthesis and delivers 6-membered N-heterocycles, including previously inaccessible pyridine derivatives. This approach can also be used as a pyridannulation methodology toward constructing polycyclic polyheteroaromatics. A computational analysis has been employed to probe plausible activation modes and to interrogate the role of the catalyst.
- De, Chandra Kanta,Gerosa, Gabriela Guillermina,List, Benjamin,Maji, Rajat,Schwengers, Sebastian Armin
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supporting information
p. 20485 - 20488
(2020/09/09)
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- Assembly of Diversely Substituted Quinolines via Aerobic Oxidative Aromatization from Simple Alcohols and Anilines
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An aerobic oxidative aromatization of simple aliphatic alcohols and anilines under the Pd(OAc)2/2,4,6-Collidine/Br?nsted acid catalytic system has been established, providing a direct approach for the preparation of diverse substituted quinoline derivatives in high yields with wide functional group tolerance. Practically, the protocol can be easily scaled up to gram-scale and was utilized in the concise formal synthesis of a promising herbicide candidate.
- Li, Jixing,Zhang, Jinlong,Yang, Huameng,Jiang, Gaoxi
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supporting information
p. 3284 - 3290
(2017/03/23)
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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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- Copper-catalyzed oxygen atom transfer of N-oxides leading to a facile deoxygenation procedure applicable to both heterocyclic and amine N-oxides
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Deoxygenation of various types of N-oxides including both heterocyclic and alkyl(aryl)amine derivatives has successfully been developed by the copper-catalyzed oxygen atom transfer using diazo compounds as the oxygen acceptor. The reaction proceeds smoothly over a broad range of substrates with excellent functional group tolerance under mild conditions. This journal is
- Jeong, Jisu,Lee, Donggun,Chang, Sukbok
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supporting information
p. 7035 - 7038
(2015/04/22)
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- A general and efficient method for the synthesis of benzo-(iso)quinoline derivatives
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A new, short and efficient synthesis of substituted benzo-(iso)quinoline derivatives is reported. The methodology is based on a Suzuki or Negishi cross-coupling followed by a cyclization reaction induced by t-BuOK in DMF to form the central ring. This approach allowed the synthesis of all four benzo-(iso)quinoline isomers and the substitution of each ring of the benzo-(iso)quinoline core.
- Mamane, Victor,Lou?rat, Frédéric,Iehl, Julien,Abboud, Mohamed,Fort, Yves
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p. 10699 - 10705
(2008/12/23)
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- Model reactions for the synthesis of azacorannulenes and related heteroaromatic compounds
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4-(2-Ethynylphenyl)pyridine (10), 3-(2-ethynylphenyl)pyridine (11), 2-(2-trimethylsilylethynylphenyl)pyridine (26), and 3-ethynyl-2-phenylpyridine (13) were prepared from readily available pyridine precursors by standard coupling reactions. Pyrolysis of 10 at 810 °C/0.5 Torr provided benzo[f]isoquinoline (45) and the benzopentalene dimer 47. Pyrolysis of 11 (820 °C/0.5 Torr) afforded benzo[f]quinoline (50), benzo[h]i-soquinoline (52), and a mixture of isomers of 47. Pyrolysis of 13 (820 °C/0.3 Torr) provided benzo[h]quinoline (56) and the novel azulene derivative azuleno[1,2-b]pyridine (58). When 26 was desilylated by treatment with TBAF in THF/water, the unusual "dimerization" product 37 was produced; its structure was confirmed by X-ray structural analysis. The mechanisms of these transformations are discussed. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Dix, Ina,Doll, Christian,Hopf, Henning,Jones, Peter G.
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p. 2547 - 2556
(2007/10/03)
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- Modification of photochemical reactivity of trans-2-styrylpyridine: Effect of cyclodextrin complexation
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In contrast to the solution irradiation of trans-2-styrylpyridine, photolysis of a γ-CD complex of the base in the solid state leads to the formation of the syn-head-to-tail dimer in fairly good yield.
- Banu, H. Shayira,Lalitha,Pitchumani,Srinivasan
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p. 607 - 608
(2007/10/03)
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- Characterization of polycyclic aromatic hydrocarbon particulate and gaseous emissions from polystyrene combustion
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The partitioning of polycyclic aromatic hydrocarbons (PAHs) between the particulate and gaseous phases resulting from the combustion of polystyrene was studied. A vertical tubular flow furnace was used to incinerate polystyrene spheres (100-300 μm) at different combustion temperatures (800- 1200 °C) to determine the effect of temperature and polystyrene feed size on the particulate and gaseous emissions and their chemical composition. The furnace reactor exhaust was sampled using real-time instruments (differential mobility particle sizer and/or optical particle counter) to determine the particle size distribution. For chemical composition analyses, the particles were either collected on Teflon filters or split into eight size fractions using a cascade impactor with filter media substrates, while the gaseous products were collected on XAD-2 adsorbent. Gas chromatography/mass spectroscopy (GC/MS) was used to identify and quantify the specific PAH species, their partitioning between the gas and particulate phases, and their distribution as a function of emission particle size. The total mass and number of PAH species in both the particulate and gas phases were found to decrease with increasing incineration temperature and decreasing polystyrene feed size, while the mean diameter of the particles increases with increasing incineration temperature and decreasing feed size. In addition, the PAH species in the particulate phase were found to be concentrated in the smaller aerosol sizes. The experimental results have been analyzed to elucidate the formation mechanisms of PAHs and particles during polystyrene combustion. The implications of these results are also discussed with respect to the control of PAH emissions from municipal waste-to-energy incineration systems. The partitioning of polycyclic aromatic hydrocarbons (PAHs) between particulate and gaseous phases resulting from the combustion of polystyrene was studied. A vertical tubular flow furnace was used to incinerate polystyrene spheres to determine the effect of temperature and polystyrene feed size on the particulate and gaseous emissions and their chemical composition. The furnace reactor exhaust was sampled using real-time instruments to determine the particle size distribution. The total mass and number of PAH species in both the particulate and gas phases were found to decrease with increasing incineration temperature and decreasing polystyrene feed size, while the mean diameter of the particles increases with increasing incineration temperature and decreasing feed size. In addition, the PAH species in the particulate phase were found to be concentrated in the smaller aerosol sizes.
- Durlak, Susan K.,Biswas, Pratim,Shi, Jichun,Bernhard, Mary Jo
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p. 2301 - 2307
(2007/10/03)
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- STUDIES ON NITROGEN-CONTAINING HETEROCYCLIC COMPOUNDS. SYNTHESES AND REACTIONS OF BENZOQUINOLINE
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The authors devised a new convinient synthesis of benzoquinoline (2) through the condensation of β-naphthylamine with malondialdehyde (MDA) followed by cyclization in polyphosphoric acid.The reactivity of 2 toward N-oxidation, Reissert reaction and methylation with methylsulfinylmethyl carbanion was investigated.
- Takeuchi, Isao,Ushida, Makoto,Hamada, Yoshiki,Yuzuri, Tomoaki,Suezawa, Hiroko,Hirota, Minoru
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p. 2221 - 2232
(2007/10/03)
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- Homogeneous and Heterogeneous Electron Transfer to Benzyl Phenyl Sulfide
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The thermodynamic and kinetic parameters of the elctron transfer (ET) to benzyl phenyl sulfide in DMF have been determined by cyclic voltammetry.The heterogeneous ET has been studied at three different electrodes: Hg, Pt, and glassy carbon.The activation parameters, namely the standard rate constant and the transfer coefficient, corrected for the double-layer contribution, show no significant difference for the three materials.The rate constants for the homogeneous ET to benzyl phenyl sulfide from eight electrogenerated anion radicals have been determined and compared with the corresponding reaction free energies, according to the current theories of the ET process.The results indicate that the ET is an endergonic process driven by a fast bond breaking of the ET product.Both the homogeneous and the heterogeneous reactions are consistent with an outer-sphere adiabatic electron-exchange process, characterized by a relatively high activation free energy.To account for the latter, inner reorganization energies must be considered, together with solvent reorganization.This is an agreement with the easy breaking of the C-S bond in the primari ET product.
- Severin, Maria Gabriella,Arevalo, Maria Carmen,Farnia, Giuseppe,Vianello, Elio
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p. 466 - 472
(2007/10/02)
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- Photochemistry of Some Azaphenanthrene N-Oxides
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1- and 4-Azaphenanthrene N-oxides undergo solvent-dependent photoisomerization, yielding naphtho-1,3-oxazepines in aprotic solvents and benzoquinolin-1(2H)-ones in water.No ring enlargement but only isomerization to the corresponding lactam is observed to take place in the case of 9-azaphenanthrene N-oxide.Measurements of the quantum yield of two photoprocesses (lactam formation and ring enlargement) confirm the difference between the photochemical behaviour of 9-azaphenanthrene N-oxide and that of the other two N-oxides examined
- Albini, Angelo,Bettinetti, Gian Franco,Minoli, Giovanna
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p. 1159 - 1161
(2007/10/02)
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