- Synthesis and Characterization of Iron-Nitrogen-Doped Graphene/Core-Shell Catalysts: Efficient Oxidative Dehydrogenation of N-Heterocycles
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An important goal for nanocatalysis is the development of flexible and efficient methods for preparing active and stable core-shell catalysts. In this respect, we present the synthesis and characterization of iron oxides surrounded by nitrogen-doped-graphene shells immobilized on carbon support (labeled FeOx@NGr-C). Active catalytic materials are obtained in a simple, scalable and two-step method via pyrolysis of iron acetate and phenanthroline and subsequent selective leaching. The optimized FeOx@NGr-C catalyst showed high activity in oxidative dehydrogenations of several N-heterocycles. The utility of this benign methodology is demonstrated by the synthesis of pharmaceutically relevant quinolines. In addition, mechanistic studies prove that the reaction progresses via superoxide radical anions (·O2-).
- Cui, Xinjiang,Li, Yuehui,Bachmann, Stephan,Scalone, Michelangelo,Surkus, Annette-Enrica,Junge, Kathrin,Topf, Christoph,Beller, Matthias
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supporting information
p. 10652 - 10658
(2015/09/28)
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- Silver-catalyzed oxidative coupling of aniline and ene carbonyl/acetylenic carbonyl compounds: An efficient route for the synthesis of quinolines
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An efficient silver-mediated coupling of aniline with ene carbonyl/acetylenic carbonyl compounds for the synthesis of quinolines is reported. The transformation is effective for a broad range of substrates, thus enabling the expansion of substituent architectures on the heterocyclic framework. The electronic properties of the substituents on the amine have been investigated. It was found that molecules with both electron-donating and electron-withdrawing substituents were suitable substrates for this transformation, and the expected products were obtained in moderate to excellent yields. The use of a single catalytic system to mediate chemical transformations in a synthetic operation is important for the development of new atom-economic strategies and this strategy is efficient in building complex structures from simple starting materials in an environmentally benign fashion.
- Zhang, Xu,Xu, Xuefeng
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supporting information
p. 3089 - 3093
(2015/02/19)
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- NMR study of O and N, O-substituted 8-quinolinol derivatives
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The 1H and 13C NMR spectral study of several biologically active derivatives of 8-quinolinol have been made through extensive NMR studies including homodecoupling and 2D-NMR experiments such as COSY-45°, NOESY, and HeteroCOSY. Electron donating resonance and electron withdrawing inductive effect of several groups showed marked changes in chemical shifts of nuclei at the seventh positions of O-substituted quinolinols (2-15). Although in N-alkyl, 8-alkoxyquinolinium halides (16-21), ring A rightly showed low frequency chemical shift values. Copyright
- Mastoor, Sobia,Faizi, Shaheen,Saleem, Rubeena,Siddiqui, Bina Shaheen
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p. 115 - 121
(2014/03/21)
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- In vitro studies of the antibacterial and antifungal activity of oxime and its derivatives
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Twenty-one derivatives of 8-hydroxyquinoline (oxine, 8H, CAS 148-24-3) were prepared and characterized by UV, IR, MS and NMR spectroscopy. Four of these derivatives, N-butyl, 8-butyloxyquinolinium bromide (HBD), 8-pentyloxyquinoline (HPEM), N-pentyl, 8-pentyloxyquinolinium bromide (HPED) and N-benzyl, 8-benzyloxy quinolinium chloride (HBED) are new and reported for the first time. The antimicrobial activity of these compounds was carried out in vitro against 11 Gram positive and 18 Gram negative bacteria, and 18 fungi including 9 dermatophytes, 7 other filamentous fungi and 2 Candida species. Three compounds namely, HPRD, HPED and HBED were found to possess significant antibacterial activity in order of HPED > HPRD > HBED, whereas 4 were found to possess significant antifungal activity in order of 8H > HT > HPEM > 8B.
- Khan,Ahmed Khan,Khalid,Ahmed,Siddiqui,Saleem,Siddiqui,Faizi
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p. 972 - 975
(2007/10/02)
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- Ameliorations et simplification de la synthese des ethers phenoliques par alkylation d'ions phenates: catalyse par transfert de phase solide-liquide sans solvant
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Several aryl ethers can be obtained in excellent yields under mild and economical conditions in the absence of organic solvents by reacting stoechiometric amounts of corresponding phenol, finely ground KOH and alkyl bromides in the presence of 2percent Aliquat 336.This method is very favourable compared with recent works dealing with anionic activation.
- Loupy, Andre,Sansoulet, Jean,Zand, Farchid Vaziri-
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p. 1027 - 1035
(2007/10/02)
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- NEGATIVE-ION MASS SPECTROMETRY OF 8-HYDROXYQUINOLINE DERIVATIVES
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The dissociative resonance electron capture mass spectra of nitro and halogen derivatives of 8-hydroxy(alkoxy)quinolines were studied with the use of the deutero analogs and model compounds.During the dissociation of 8-alkoxyquinolines the - fragments (R=CH3 and C2H5) are formed, and their peak intensities and resonance energies depend on the electron-withdrawing characteristics of the substituents in the benzene ring.The electron densities at the atoms and the bond orders in the - anions and neutral molecules were calculated by the CNDO/2 method.The negative charge in such anions is lo calized predominatly at the oxygen atom.By means of the deuterium-labeled compounds it was established that during the dissociation of 8-hydroxyquinolines the - anion is formed through the elimination of hydrogen both from the hydroxyl group and from the carbon atoms of the ring.
- Ermakov, A. I.,Khvostenko, O. G.,Voronin, V. G.,Sorokin, A. A.,Asfandiarov, N. L.,Khvostenko, V. I.
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p. 2140 - 2145
(2007/10/02)
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- MASS SPECTROMETRY OF 8-HYDROXYQUINOLINE DERIVATIVES
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In contrast to the fragmentation of the corresponding alkyl aryl ethers, characteristic + and + fragments were observed in the fragmentation of 5-nitro(halo)-substituted 8-alkoxyquinolines.It was found by means of deuterium labeling that a hydrogen atom is split out primarily from the alkoxy group.It was demonstrated that an + fragment was from the + ion, which has a three-ring structure and quaternary nitrogen atom.The formation of an + fragment is characteristic for the fragmentation of 5(7)-nitro(halo)-substituted 8-hydroxyquinolines.The interrelationship between the intensities of the +, +, and + ion peaks and the protonation constants (pKa) of the investigated compounds is discussed.
- Ermakov, A. I.,Voronin, V. G.,Sorokin, A. A.,Epshtein, N. I.,Muravskaya, I. D.,et al.
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p. 637 - 642
(2007/10/02)
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- SOLID-LIQUID PHASE TRANSFER CATALYSIS WITHOUT SOLVENT: A MILD AND EFFICIENT PREPARATION OF MONO AND DI-ETHERS DERIVED FROM 8-HYDROXYQUINOLINE
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The title compounds are easily prepared by reaction of 8-hydroxyquinoline with either 1 eq.CnH2n+1Br (2/=n/=16) or 0.5 eq.Br(CH2)nBr (3/=n/=6) in the presence of 1 eq. finely ground KOH and 2percent Aliquat 336.Reactions are performed in the absence of any organic solvent.Yields and experimental conditions compare very favourably to those obtained previously by classical methods.
- Bram, G.,Loupy, A.,Sansoulet, J.,Strzelecka, H.
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p. 889 - 898
(2007/10/02)
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