- Selective reduction of carboxylic acids to aldehydes catalyzed by B(C 6F5)3
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B(C6F5)3 efficiently catalyzes hydrosilylation of aliphatic and aromatic carboxylic acids to produce disilyl acetals under mild conditions. Catalyst loadings can be as low as 0.05 mol %, and bulky tertiary silanes are favored to give selectively the acetals. Acidic workup of the disilyl acetals results in the formation of aldehydes in good to excellent yields.
- Bezier, David,Park, Sehoon,Brookhart, Maurice
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supporting information
p. 496 - 499
(2013/03/29)
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- Kinetics and mechanism of the oxidation of aliphatic primary alcohols by imidazolium fluorochromate
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The oxidation of nine aliphatic primary alcohols by imidazolium fluorochromate (IFC) in dimethylsulphoxide leads to the formation of corresponding aldehydes. The reaction is first order with respect to IFC. A Michaelis-Menten type kinetics is observed with respect to alcohols. The reaction is promoted by hydrogen ions; the hydrogen-ion dependence has the form : kobs = a + b [H+]. The oxidation of [1,1- 2H2]ethanol (MeCD2OH) exhibits a substantial primary kinetic isotope effect (kH/kD = 5.87 at 298 K). The reaction has been studied in nineteen different organic solvents. The solvent effect was analysed using Taft's and Swain's multiparametric equations. The rate of oxidation is susceptible to both polar and steric effects of the substituents. A suitable mechanism has been proposed.
- Gehlot,Gilla,Mishra,Sharma, Vinita
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experimental part
p. 685 - 692
(2012/04/04)
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- Synthesis, characterization, redox, catalytic, and antibacterial activities of binuclear ruthenium(III) schiff base complexes containing triphenylphosphine as co-ligand
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New hexa-coordinated binuclear Ru(III) Schiff base complexes of the type [(PPh3)2X2Ru]2L (where, X = Cl or Br; L = binucleating N2O2 Schiff bases) have been synthesized and characterized by elemental analysis, magnetic susceptibility measurement, FT-IR, UV-vis, 13C1H-NMR, ESR, cyclic voltammetric, SEM and powder X-ray diffraction pattern. The new complexes have been used as catalyst in C C coupling reaction and the oxidation of alcohols to their corresponding carbonyl compounds by using molecular oxygen atmosphere at ambient temperature. Further, the new Schiff base ligands and their Ru(III) complexes were also screened for their antibacterial activity against K. pneumoniae, Shigella sp., M. luteus, E. coli and S. typhi. From this study, it was found out that the activity of the ruthenium(III) Schiff base complexes almost reaches the effectiveness of the conventional bacteriocide standards. Copyright Taylor & Francis Group, LLC.
- Manimaran, Arumugam,Jayabalakrishnan, Chinnasamy
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experimental part
p. 116 - 128
(2010/08/13)
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- Biocidal and catalytic efficiency of ruthenium(III) complexes with tridentate Schiff base ligands
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The reaction of the Schiff bases (obtained by condensing isatin with o-aminophenol/o-aminothiophenol/o-aminobenzoic acid) with [RuX 3(EPh3)3] (where X = Cl/Br; E = P/As) in benzene afforded new, air-stable Ru(III) complexes of the general formula [Ru(L)X(EPh3)2] (L = dianion of tridentate Schiff bases). In all these reactions, the Schiff base ligand replaces one triphenylphosphine/ triphenylarsine and two chlorides/bromides from the ruthenium precursors. The complexes were characterized by elemental analyses, spectral (FT-IR, UV-vis,1H and 13C NMR for the ligands, and EPR) and electrochemical studies. All the metal complexes exhibit characteristic LMCT absorption bands in the visible region. The catalytic reactivity proved these complexes to be efficient catalysts in the oxidation of alcohols and C-C coupling. All the complexes were screened for their biocidal efficiency against bacteria such as Staphylococcus epidermidis and Escherichia coli and fungi such as Botrytis cinerea and Aspergillus niger at 0.25,0.50 and 1 % concentrations.
- Arunachalam,Priya, N. Padma,Boopathi,Jayabalakrishnan,Chinnusamy
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experimental part
p. 491 - 498
(2010/10/18)
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- Oxidation of aliphatic primary alcohols by morpholinium chlorochromate: A kinetic and mechanistic approach
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The oxidation of nine aliphatic primary alcohols by morpholinium chlorochromate (MCC) in dimethylsulfoxide leads to the transformation of alcohols to the corresponding aldehydes. The reaction is first order with respect to both MCC and the alcohol both. The reaction is catalysed by hydrogen ions. The hydrogen-ion dependence has the form: kobs = a + A[H +]. The oxidation of [1,1-2H2]ethanol (MeCD2OH) exhibits a substantial primary kinetic isotope effect. The reaction has been studied in nineteen different organic solvents. The solvent effect was analysed using Taft's and Swain's multiparametric equations. The rate of oxidation is susceptible to both polar and steric effects of the substituents. A suitable mechanism has been proposed.
- Choudhary,Yajurvedi,Soni,Agarwa,Sharma, Vinita
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experimental part
p. 1061 - 1066
(2011/05/05)
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- Reaction of zirconium alkoxides with tert-butyl hydroperoxide. Oxidative ability of the Zr(OBu-t)4-t-BuOOH system
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Oxidation of the isopropoxy group in the Zr(i-PrO)4·i- PrOH complex involves both direct reaction with tert-butyl hydroperoxide and intermediate formation of zirconium peroxy compound. Zirconium tetra-tert-butoxide reacts with tert-bytyl hydroperoxide to form metal-containing peroxide and trioxide. Decomposition of the latter leads to oxygen evolution and is accompanied by radical formation. The alkoxyl and peroxyl radicals formed were identified by ESR spectroscopy. The nature of the oxidant (oxygen, zirconium-containing peroxide and-trioxide) in the Zr(OBu-t)4-t-BuOOH system is determined by the structure of the substrate molecule. Pleiades Publishing, Inc., 2006.
- Gulenova,Stepovik,Cherkasov
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p. 980 - 988
(2008/02/03)
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- Oxidation of unactivated primary aliphatic amines catalyzed by an electrogenerated 3,4-azaquinone species: A small-molecule mimic of amine oxidases
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High catalytic performance of the electrogenerated amine oxidase mimic 3,4-iminoquinone 1ox is observed under metal-free conditions in the chemoselective oxidation reaction of unactivated primary aliphatic amines.
- Largeron, Martine,Neudorffer, Anne,Fleury, Maurice-Bernard
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p. 1026 - 1029
(2007/10/03)
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- Quantitative RP-HPLC determination of some aldehydes and hydroxyaldehydes as their 2,4-dinitrophenylhydrazone derivatives
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A high-performance liquid chromatographic (HPLC) method is described for the quantitative determination of some aliphatic aldehydes and β- hydroxyaldehydes as their 2,4-dinitrophenylhydrazone derivatives. A method is described for the preparation of deriv
- Koivusalmi,Haatainen,Root
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- Transformation of acid chlorides into aldehydes by reduction of in-situ formed acyltributylphosphonium ions with zinc-copper couple or zinc
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Transformation of acid chlorides into the corresponding aldehydes without over-reduction to alcohols was effectively achieved by the reduction of acyltributylphosphonium ions, formed in-situ from the chlorides and tributylphosphine in CH3CN, with Zn-Cu couple or Zn in the presence of CH3SO3H under an N2 atmosphere.
- Maeda, Hatsuo,Maki, Toshihide,Ohmori, Hidenobu
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p. 2247 - 2250
(2007/10/02)
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- KINETICS OF THE FORMATION OF 2,4-DINITROPHENYLHYDRAZONES IN HYDROCARBONS
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The kinetics of the formation of 2,4-dinitrophenylhydrazones in a hydrocarbon medium were studied.By an integral method it was found that the reaction of carbonyl compounds with 2,4-dinitrophenylhydrazine is reversible, and the forward and reverse reactio
- Kuznetsova, E. V.,Mil'kina, T. N.,Morzhakova, T. M.,Taranenko, S. A.,Kudinova, L. M.,Batalin, O. E.
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p. 1914 - 1918
(2007/10/02)
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