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Selective Reduction (selective + reduction)
Selected AbstractsLiquid-Liquid-Liquid Phase Transfer Catalysis: A Novel and Green Concept for Selective Reduction of Substituted NitroaromaticsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2005Ganapati Abstract The selective reduction of nitroaromatics to the corresponding amines is an important transformation since many aromatic amines exhibit biological activities and find a multitude of industrial applications, being intermediates for the synthesis of dyes, pharmaceuticals and agrochemicals. A variety of nitroaromatics dissolved in organic solvents was reduced by using aqueous sodium sulfide, and tetrabutylammonium bromide (TBAB) as the phase transfer catalyst by choosing appropriate concentrations which resulted in three immiscible liquid phases. Compared to L-L PTC, the L-L-L PTC offers much higher rates of reaction, better selectivities and repeated use of catalyst. The selectivities for the desired products were 100%. [source] Kinetic Reaction Models for the Selective Reduction of NO by Methane over Multifunctional Zeolite-based Redox CatalystsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 12 2004T. Sowade Abstract Kinetic measurements of the selective catalytic reduction (SCR) of NO by methane were performed over CeO2/H-ZSM-5, In-ZSM-5, and CeO2/In-ZSM-5 catalysts. The parameter space covered NO, CH4, and O2 concentrations varying from 250 to 1000 ppm, from 500 to 2000 ppm, and from 0.5 to 10,vol.-%, respectively, space velocities between 5000 and 90000 h,1 and temperatures between 573 and 873 K depending on the catalyst activities. With CeO2/In-ZSM-5 an additional series of measurements was performed with moistened feed gas (0.5,10,vol.-% H2O). On the basis of a pseudo-homogeneous, one-dimensional fixed-bed reactor model, the data were fitted to a kinetic model that includes power rate laws for the reduction of NO and for the unselective total oxidation of methane. From analyses of isothermal data sets, almost all reaction orders were found to vary significantly with changing temperature, which indicates that the simple kinetic model cannot reflect the complex reaction mechanism correctly. Nevertheless, the data measured with In-ZSM-5 could be modeled with good accuracy over a wide range of reaction temperatures (150 K) while the accuracy was less satisfactory with the remaining data sets, in particular for data with the moist feed over CeO2/In-ZSM-5. With the latter catalyst it was not possible to represent the data measured in dry and in moist feed in a single model even upon confinement to fixed reaction temperatures. A comparison of the separate models established showed strong changes in the reaction orders in the presence of water, which occur apparently already at a very low water content (,,0.5,vol.-%). The kinetic parameters found are in agreement with earlier conclusions about the reaction mechanisms. With In-ZSM-5, both reaction orders and the activation energy show a rate-limiting influence of NO oxidation on the NO reduction path which is removed by the presence of the CeO2 promoter. A difference in the reaction mechanism over CeO2/In-ZSM-5 and CeO2/H-ZSM-5 is reflected in different kinetic parameters. The differences of the kinetic parameters between dry-feed and moist-feed models for CeO2/In-ZSM-5 reflect adsorption competition between the reactants and water. [source] ChemInform Abstract: Iron-Catalyzed Selective Reduction of Nitro Compounds to Amines.CHEMINFORM, Issue 30 2010Leyla Pehlivan Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Iron-Catalyzed Selective Reduction of Nitroarenes to Anilines Using Organosilanes.CHEMINFORM, Issue 28 2010Kathrin Junge Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A New Reagent for Selective Reduction of Nitro Group.CHEMINFORM, Issue 2 2010B. Raju Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: An Efficient Selective Reduction of Aromatic Azides to Amines Employing BF3×OEt2/NaI: Synthesis of Pyrrolobenzodiazepines.CHEMINFORM, Issue 39 2008Ahmed Kamal Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Environmentally Benign and Selective Reduction of Nitroarenes with Fe in Pressurized CO2,H2O Medium.CHEMINFORM, Issue 33 2008Ge Gao Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Stereoselective Debromination and Selective Reduction of vic-Dibromides with Nickel Boride.CHEMINFORM, Issue 15 2007Jitender M. Khurana Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Selective Reduction of Aromatic Nitro Groups in the Presence of Amide Functionality.CHEMINFORM, Issue 39 2006Dibakar Chandra Deka Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Selective Reduction of Carbonyl Compounds with B-Phenoxydiisopinocampheylborane: Comparison of Its Reactivity to the Cyclohexoxy Derivative.CHEMINFORM, Issue 22 2005Jin Soon Cha Abstract For Abstract see ChemInform Abstract in Full Text. [source] Selective Reduction of Azoarenes into Arylamine(s) by Aluminum/NH4Br under Sonic Conditions.CHEMINFORM, Issue 42 2004M. A. Pasha Abstract For Abstract see ChemInform Abstract in Full Text. [source] Selective Reduction of Alkenes, ,,,-Unsaturated Carbonyl Compounds, Nitroarenes, Nitroso Compounds, N,N-Hydrogenolysis of Azo and Hydrazo Functions as well as Simultaneous Hydrodehalogenation and Reduction of Substituted Aryl Halides over PdMCM-41 Catalyst under Transfer Hydrogen Conditions.CHEMINFORM, Issue 30 2004Parasuraman Selvam No abstract is available for this article. [source] Selective Reduction of C=O in ,,,-Unsaturated Carbonyls Through Catalytic Hydrogen Transfer Reaction over Mixed Metal Oxides.CHEMINFORM, Issue 20 2004Sachin U. Sonavane Abstract For Abstract see ChemInform Abstract in Full Text. [source] Investigation of the Selective Reduction of Isatin Derivatives.CHEMINFORM, Issue 2 2004-Hydroxyacetophenone Derivatives, 3-(Ethylenedioxy)-2-hydroxyindoline Carboxylates., Ethyl spiro-, Synthesis of Abstract For Abstract see ChemInform Abstract in Full Text. [source] Molecular Diversity from Tonghaosu Analogues, Selective Reduction of the endo-Cyclic Double Bond of Tonghaosu Analogues and the Synthesis of Cyclopentenone Derivatives.CHEMINFORM, Issue 23 2003Biao-Lin Yin Abstract For Abstract see ChemInform Abstract in Full Text. [source] Selective Reduction of Fullerene C60 by Metals in Neutral and Alkaline Media.CHEMINFORM, Issue 18 2003Interaction of C60 with KOH Abstract For Abstract see ChemInform Abstract in Full Text. [source] Selective Reduction of Stereodefined Cyclopropyl Substituted Acrylate Esters to the Corresponding Propionate Esters.CHEMINFORM, Issue 4 2003Rong He Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: New Pd-Catalyzed Selective Reduction of Carboxylic Acids to Aldehydes.CHEMINFORM, Issue 29 2002Lukas J. Goossen Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Sulfurated Borohydride Exchange Resin: A Novel Reagent for Selective Reduction of Aldehydes.CHEMINFORM, Issue 1 2002B. P. Bandgar Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Selective Reduction of the Acyl Group in Cyclic ,-Acyl-,-dicarbonyl Compounds with Sodium Cyanoborohydride.CHEMINFORM, Issue 49 2001-Alkyl-, -dicarbonyl Compounds., Efficient Synthesis of Cyclic Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Indium/Ammonium Chloride Mediated Selective Reduction of Aromatic Nitro Compounds: Practical Synthesis of 6-Aminochrysene.CHEMINFORM, Issue 1 2001Bimal K. Banik Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Selective reduction by isolation rearing of 5-HT1A receptor-mediated dopamine release in vivo in the frontal cortex of miceJOURNAL OF NEUROCHEMISTRY, Issue 2 2002Y. Ago Abstract Serotonin (5-HT)1A receptors modulate in vivo release of brain monoaminergic neurotransmitters which may be involved in isolation-induced aggressive behavior. The present study examined the effect of isolation rearing on the 5-HT1A receptor-mediated modulation of dopamine (DA), 5-HT and noradrenaline (NA) release in the frontal cortex of mice. The selective 5-HT1A receptor agonist (S)-5-{3-[(1,4-benzodioxan-2-ylmethyl)amino]propoxy}-1,3-benzodioxole HCl (MKC-242) increased the release of DA and NA and decreased the release of 5-HT in the frontal cortex of mice. The effect of MKC-242 on DA release was significantly less in isolation-reared mice than in group-reared mice, while effects of the drug on NA and 5-HT release did not differ between both groups. The effect of the other 5-HT1A receptor agonist 8-hydroxy-2-(di- n -propylamino)tetralin on cortical DA release was also less in isolation-reared mice than in group-reared mice, and that of the drug on cortical 5-HT release did not differ between both groups. In contrast to MKC-242-induced DA release, amphetamine-induced increase in cortical DA release in vivo was greater in isolation-reared mice. The present findings suggest that isolation rearing enhances the activity of cortical dopaminergic neurons and reduces selectively the 5-HT1A receptor-mediated release of DA in the cortex. [source] Ji Q, Chang L, VanDenBerg D, Stanczyk FZ, Stolz A. Selective reduction of AKRIC2 in prostate cancer and its role in DHT metabolism.THE PROSTATE, Issue 4 2006Prostate 2003;54(4):27 No abstract is available for this article. [source] Thiopropyl-agarose as a solid phase reducing agent for chemical modification of IgG and F(ab,)2BIOTECHNOLOGY PROGRESS, Issue 5 2008Natalia Ferraz Abstract Selective reduction of native disulfide bonds in immunoglobulins is one of the best methods for introducing reactive groups on to the protein surface. Additionally, the thiol groups so generated may allow oriented conjugation at a specific site of the immunoglobulin. Solid-phase reducing agents have many advantages over soluble ones (including ease of separation of excess reagent from reduced protein by filtration, and the potential for regeneration and multiple reuse). In this work we report a comparative study of the reduction of rabbit IgG and its F(ab,)2 fragments, with mercaptohydroxypropylether-agarose (thiopropyl-agarose), a solid phase reducing agent, and dithiothreitol. The effect of different parameters on the process, such as the amount of reducing agent, incubation period, and temperature, was assessed by titration of thiol groups and SDS-PAGE analysis. Optimized reduction with thiopropyl-agarose introduced six thiol groups in the F(ab,)2 fragment (mol/mol). Native IgG was less reactive, probably due to steric effects, as only an average of three thiol groups were introduced. However, by increasing reaction temperature from 22 to 37°C, six thiol groups could be introduced in native IgG (mol/mol). Reduction with dithiothreitol also introduced six thiol groups in F(ab,)2 fragments (mol/mol) but led to higher thiol content for the whole IgG. These results demonstrated that thiopropyl-agarose can be a very useful tool for exercising more precise control over the reduction treatment, and for selecting which disulfide bridges are to be broken. After 6 h incubation with reducing agent containing 8 and 16 ,moles SH per mg of protein, the resulting reduced IgG retained the same biological activity as the native immunoglobulin. The controlled modification of native disulfides achieved with thiopropyl-agarose will be useful for the development of soluble and insoluble immunoglobulin conjugates. [source] GluR3 subunit regulates sleep, breathing and seizure generationEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2008Hendrik W. Steenland Abstract The functional role of GluR3 AMPA (,-amino-3-hydroxy-5-methylisoxazole-4-propionic acid) receptor subunits has remained elusive. In vitro studies of genetic knockout mice have not yielded significant alterations in synaptic communication. However, behavioural approaches utilizing knockout mice have shown that the subunit may be involved in exploration and motor coordination, suggesting that in vivo methodologies may be more forthcoming. We tested the hypothesis that GluR3 subunits are involved in the modulation of neural network activity. We used a freely behaving mouse model to examine the effect of GluR3,/, on field potential recordings of electroencephalogram, vital functions (i.e. breathing and heart rate) and muscle tone across natural sleep and wakefulness states. We found that GluR3,/, mice virtually lack electroencephalographic signatures of NREM sleep (n = 9) as demonstrated by reduction in electroencephalogram power in the low-frequency bands (,1, ,2 and ,). In addition, three of nine GluR3,/, mice expressed seizure activity during wakefulness and sleep, suggesting that deletion of the GluR3 gene may predispose to seizure. GluR3 gene knockout also produced state-dependent respiratory modulation, with a selective reduction in breathing rate during behavioural inactivity. These findings show that GluR3 subunits have diverse neurophysiological impact, modulating oscillatory networks for sleep, breathing and seizure generation. Finally, this is the first study to demonstrate the feasibility of direct diaphragm electromyogram recordings in freely behaving mice. [source] Preparation of high specific activity tritium labeled 6,,9,-difluoro-11,,21-dihydroxy-16,,17-[(1-methylethylidene)bis(oxy)]pregna-1,4-diene-3,20-one, fluocinolone acetonideJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 4 2009D. Zhong Abstract Fluocinolone acetonide was tritiated by selective reduction of the 1,2-double bond of the O -protected analog under tritium, followed by re-establishment of the 1,2-double bond and deprotection. Protection of both hydroxyl functionalities was required. The product was obtained with specific activity 36.8,Ci/mmol. Copyright © 2009 John Wiley & Sons, Ltd. [source] Synthesis of tritium- and deuterium-labeled budesonideJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 1 2008Bachir Latli Abstract Tritium-labeled budesonide was prepared by the selective reduction of a double bond in the butenylenedioxy side chain using carrier-free tritium and palladium on carbon as a catalyst in absolute ethanol. Although the reduction gave a mixture of the desired product and the expected byproducts resulting from over reduction of the other double bonds in ring A, the desired tritium-labeled budesonide was easily isolated by reverse phase HPLC and with specific activity of 54,Ci/mmol. [D8]-budesonide was prepared from 16,-hydroxyprednisolone and D8 -butyraldehyde in 1,4-dioxane in the presence of perchloric acid. The isotopic enrichment was found to be more than 99,atom% D. Copyright © 2008 John Wiley & Sons, Ltd. [source] Radical copolymerization of vinylidene fluoride with 1-bromo-2,2-difluoroethyleneJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2010G. K. Kostov Abstract The radical copolymerization of vinylidene fluoride (VDF) and 1-bromo-2,2-difluoroethylene (BDFE) in 1,1,1,3,3-pentafluorobutane solution at different monomer molar ratios (ranging from 96/4 to 25/75 mol %) and initiated by tert -butylperoxypivalate (TBPPI, mainly) is presented. Poly(VDF- co -BDFE) copolymers of various aspects (from white powders to yellow viscous liquids) were produced depending on the copolymer compositions. The microstructures of the obtained copolymers were characterized by 19F and 1H NMR spectroscopy and by elementary analysis and these techniques enabled one to assess the contents of both comonomers in the produced copolymers. VDF was shown to be more incorporated in the copolymer than BDFE. From the extended Kelen and Tudos method, the kinetics of the radical copolymerization led to the determination of the reactivity ratios, ri, of both comonomers (rVDF = 1.20 ± 0.50 and rBDFE = 0.40 ± 0.15 at 75 °C) showing that VDF is more reactive than BDFE. Alfrey-Price's Q and e values of BDFE monomer were calculated to be 0.009 (from QVDF = 0.008) or 0.019 (from QVDF = 0.015) and +1.22 (vs. eVDF = 0.40) or +1.37 (vs. eVDF = 0.50), respectively, indicating that BDFE is an electron-accepting monomer. Statistic cooligomers were produced with molar masses ranging from 1,800 to 5,500 g/mol (assessed by GPC with polystyrene standards). A further evidence of the successful copolymerization was shown by the selective reduction of bromine atoms in poly(VDF- co -BDFE) cooligomers that led to analog PVDF. The thermal properties of the poly(VDF- co -BDFE) cooligomers were also determined and those containing a high VDF amount exhibited a high thermal stability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3964,3976, 2010. [source] CryolipolysisÔ for subcutaneous fat layer reduction,LASERS IN SURGERY AND MEDICINE, Issue 10 2009Mathew M. Avram MD Abstract Background and Objective Cryolipolysis is a unique non-invasive method for the selective reduction of fat cells with controlled, localized cooling. It is important, therefore, to understand the potential efficacy and safety of this new procedure for fat layer reduction. Materials and Methods A review of the literature associated with cryolipolysis was performed to evaluate the findings from pre-clinical and clinical studies with respect to the mechanism of action, efficacy, and safety. Results Cryolipolysis has demonstrated efficacy in both human and animal studies. Histology findings also confirm the selective reduction of fat in both humans and animals, with evidence of a gradual thinning of the fat layer over a period of two to four months. Importantly, cryolipolysis has not produced any significant adverse side effects in studies to date and any noted effects have been minor and temporary. Conclusion Although the mechanism of action for cryolipolysis is not yet completely understood, the efficacy and safety of this non-invasive procedure for fat layer reduction has been demonstrated in the studies available to data. Further studies willl assist in identifying the mechanism and elucidate the full potential of this technology to perform safe, non-invasive fat reduction for areas of local fat accumulation. Lasers Surg. Med. 41:703,708, 2009. © 2009 Wiley-Liss, Inc. [source] Evidence of cell-nonautonomous changes in dendrite and dendritic spine morphology in the met-signaling,deficient mouse forebrainTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 21 2010Matthew C. Judson Abstract Human genetic findings and murine neuroanatomical expression mapping have intersected to implicate Met receptor tyrosine kinase signaling in the development of forebrain circuits controlling social and emotional behaviors that are atypical in autism-spectrum disorders (ASD). To clarify roles for Met signaling during forebrain circuit development in vivo, we generated mutant mice (Emx1Cre/Metfx/fx) with an Emx1-Cre-driven deletion of signaling-competent Met in dorsal pallially derived forebrain neurons. Morphometric analyses of Lucifer yellow-injected pyramidal neurons in postnatal day 40 anterior cingulate cortex (ACC) revealed no statistically significant changes in total dendritic length but a selective reduction in apical arbor length distal to the soma in Emx1Cre/Metfx/fx neurons relative to wild type, consistent with a decrease in the total tissue volume sampled by individual arbors in the cortex. The effects on dendritic structure appear to be circuit-selective, insofar as basal arbor length was increased in Emx1Cre/Metfx/fx layer 2/3 neurons. Spine number was not altered on the Emx1Cre/Metfx/fx pyramidal cell populations studied, but spine head volume was significantly increased (,20%). Cell-nonautonomous, circuit-level influences of Met signaling on dendritic development were confirmed by studies of medium spiny neurons (MSN), which do not express Met but receive Met-expressing corticostriatal afferents during development. Emx1Cre/Metfx/fx MSN exhibited robust increases in total arbor length (,20%). As in the neocortex, average spine head volume was also increased (,12%). These data demonstrate that a developmental loss of presynaptic Met receptor signaling can affect postsynaptic morphogenesis and suggest a mechanism whereby attenuated Met signaling could disrupt both local and long-range connectivity within circuits relevant to ASD. J. Comp. Neurol. 518:4463,4478, 2010. © 2010 Wiley-Liss, Inc. [source] | ||||||||||||||||