- Selective iron-catalyzed oxidation of phenols and arenes with hydrogen peroxide: Synthesis of vitamin e intermediates and vitamin k3
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(Figure Presented). Pumping iron! Convenient iron-based catalyst systems for the selective oxidation of arenes and phenols with hydrogen peroxide to give 1, 4-quinones have been developed. This selective oxidation reaction takes place under mild conditions (room temperature, alcoholic solvents) with H 2O2 as the terminal oxidant.
- Moeller, Konstanze,Wienhoefer, Gerrit,Schroeder, Kristin,Join, Benoit,Junge, Kathrin,Beller, Matthias
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experimental part
p. 10300 - 10303
(2010/10/21)
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- Bis(trifluoroacetoxyiodo)benzene-induced activation of tert-butyl hydroperoxide for the direct oxyfunctionalization of arenes to quinones
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Various aromatic hydrocarbons were oxidized with bis(trifluoroacetoxyiodo) benzene (PIFA)/tert-butyl hydroperoxide system to afford the corresponding quinones. The reaction conditions and scope have been discussed in detail.
- Catir, Mustafa,Kilic, Hamdullah
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p. 2151 - 2154
(2007/10/03)
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- Chromium(VI) oxide-catalyzed oxidation of arenes with periodic acid
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Chromium(VI) oxide was found to catalyze the oxidation of arenes such as naphthalenes and anthrathene to the corresponding quinones with periodic acid as the terminal oxidant in acetonitrile. 2-Methylnaphthalene was oxidized smoothly to 2-methyl-1,4-naphthoquinone (vitamin K3) by the catalytic system in high yield and regioselectivity.
- Yamazaki, Shigekazu
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p. 3355 - 3357
(2007/10/03)
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- Dimethyl sulfoxide and anhydrous copper (II) sulfate as alkylating reagent for 1,4-quinones
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1,4-Quinones and its derivatives have been alkylated by dimethyl sulfoxide in the presence of anhydrous copper (II) sulfate at the active quinonoid position selectively, in a facile single step reaction with good yields.
- Bansal,Thapliyal,Khanna
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p. 1669 - 1675
(2007/10/02)
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- ELECTRON-TRANSFER PROCESSES: MECHANISMS OF OXIDATION OF ETHERS AND ESTERS BY SILVER-CATALYZED PEROXYDISULPHATE
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Nucleophilic carbon-centred radicals, generated from the oxidation of diethyl ether, ethyl acetate, propyl acetate, ethyl propionate, diethyl oxalate and 2-phenylethyl acetate by silver-catalyzed decomposition of peroxydisulphate, have been trapped, mostly by naphthoquinone and in a few cases by protonated quinoline. Characterization of the intermediate radicals allows the rationalization of the mechanism of these oxidations, which are likely to occur through an initial electron-transfer step by Ag(II).
- Minisci, Francesco,Coppa, Fausta,Fontana, Francesca,Zhao, Lihua
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p. 613 - 616
(2007/10/02)
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- HOMOLYTIC ALKYLATION OF NAPHTHOQUINONE AND METHYL-NAPHTHOQUINONE. ENTHALPIC, STERIC AND POLAR EFFECTS.
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The homolytic methylation of naphthoquinone to obtain menadione has been investigated by three sources of methyl radical: t-BuOOH, DMSO and H2O2, acetone and H2O2.Moreover the homolytic alkylation of naphthoquinone and 2-methylnaphthoquinone has been investigated by using alkyl iodides as sources of alkyl radicals.
- Coppa, F.,Fontana, F.,Minisci, F.,Barbosa, M. C. Nogueira,Vismara, E.
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p. 7343 - 7352
(2007/10/02)
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- Synthesis of 2,3-Dialkyl-6,7-dichloro- and 2,3-Dialkyl-6,7-dibromo-1,4-naphthoquinones
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Thermal treatment of 1,4-benzoquinone and its 2-methyl and 2,3-dimethyl homologues with 3,4-dichlorothiophene 1,1-dioxide followed by oxidation affords the corresponding 6,7-dichloro-1,4-naphthoquinones; the parent compound and its 2-methyl homologue can be alkylated at the free quinonoid positions using the alkanoic acid-persulphate-silver ion system.Nitration of 2,3-dibromonaphthalene yields 2,3-dibromo-5-nitronaphthalene, which via sequential reduction, diazotisation, hydrolysis, and oxidation with Fermy's salt gives 6,7-dibromo-1,4-naphthoquinone, which can be similarly alkylated.
- Ashnagar, Alamdar,Bruce, J. Malcolm,Lloyd-Williams, Paul
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p. 559 - 562
(2007/10/02)
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- PREPARATION OF NAPHTHALDEHYDES BY CERIUM(IV)AMMONIUM NITRATE OXIDATION OF METHYLNAPHTHALENES.
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Naphthalenes with an Me group in the 1-position gave aldehydes in good to excellent yields when oxidized with cerium(IV) ammonium nitrate (CAN) in 50percent HOAc at 85 deg C.Under the same conditions methylnaphthalenes with no Me group in a peri position gave aldehydes in fair yields but also significant amounts of 1,4-naphthoquinone.
- Sydnes, Leiv K.,Burkow, Ivan C.,Hansen, Sissel H.
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p. 5703 - 5706
(2007/10/02)
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- CERIUM CATALYZED PERSULFATE OXIDATION OF POLYCYCLIC AROMATIC HYDROCARBONS TO QUINONES
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A practical synthesis of polycyclic quinones from the parent hydrocarbons is described.The twophase oxidation of hydrocarbons was accomplished by using ammonium persulfate in the catalytic presence of cerium ammonium sulfate, silver nitrate, and sodium dodecyl sulfate.The reaction conditions and scope have been discussed in detail.
- Skarzewski, Jacek
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p. 4997 - 5000
(2007/10/02)
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- PHOTOOXYGENATIONS PAR TRANSFERT D'ELECTRON SENSIBILISEES PAR LE DICYANO-9,10 ANTHRACENE. ROLE DU SOLVANT ET FORMATION D'OXYGENE SINGULET.
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Photooxygenation of naphtalenic compounds sensitized by electron acceptors like 9,10 dicyanoanthracene (DCA) is shown to proceed by two distinct ways depending on the solvent polarity.In a polar solvent superoxide ion (O2-.) as well as singlet oxygen (1O2*) are involved while in a non polar solvent only singlet oxygen is produced.
- Santamaria, J.,Gabillet, P.,Bokobza, L.
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p. 2139 - 2142
(2007/10/02)
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- Dimeric Naphthoquinones, XI. - Oxidation Products of Substituted Binaphthyls
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1',4,4'-Trimethoxy-2,2'-binaphthyl-1-ol (7a) is oxidized in high yield forming the quinone 8a or the cyclic acetal 22.Under acidic conditions, both compounds are easily transferred into substituted dinaphthofurans.
- Laatsch, Hartmut
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p. 1367 - 1381
(2007/10/02)
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- PHOTOCHEMICAL REACTION OF EPOXYNAPHTHOQUINONES WITH ALCOHOLS. AN IONIC TRAPPING OF CARBONYL YLIDES
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Irradiation of several 2,3-dialkyl-2,3-epoxy-2,3-dihydro-1,4-naphthoquinones in the presence of alcohol gave ring-contracted alcohol-adducts via nucleophilic addition of alcohol to carbonyl ylides.
- Osuka, Atsuhiro,Suzuki, Hitomi,Maruyama, Kazuhiro
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p. 201 - 204
(2007/10/02)
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