oxidation oxidation of alcohols by chromium reagents

... determination of laccase activity Fig Mechanisms of the O2-laccase-HPI (A) and O2-laccaseTEMPO (B) oxidation of substrates 1–5 (Fig 2) The activity of laccase was determined by following the rate of oxidation ... the oxidation reaction Substrate consumption Table summarizes the results of our laccase oxidations of substrates 1–5, and the effect of the cosolvent and of the mediators on the amount of substrate ... could be detected by LC-MS, even though the formation of small amounts of olefinic products is indicated by 1H-NMR spectra also in this case (Fig 4) There is no evidence of oxidation of the internal...

Ngày tải lên: 21/02/2014, 01:21

... in the case of oxidation of 5, the reaction temperature provided by microwave or conventional heating increased the yield of 5b, ii) in case of the oxidation of 4, the assistance of microwave ... molar ratio of substrate, KMnO4, and CuSO4 5H2O was 3:12:24 This ratio, observed again also for the oxidation of indane, confirmed that it was the best molar ratio for the oxidation of alkylarenes ... 9-Fluorenone (8a) Fig Structure of substrates and products in the oxidation of alkylarenes 2.RESULTS AND DISCUSSION The stoichiometric factor investigated on the oxidation of diphenylmethane in two...

Ngày tải lên: 22/07/2014, 03:20

... Transformation of citrate by MnO2 19 Figure I.8 – Proposed reaction pathway of oxidation of triclosan by MnO2 [63] 21 Figure I.9 – Proposed Reaction Scheme for Oxidation of FQs by MnO2 ... Impact of NOM on oxidation and hydrolysis of micropollutant by MnO2 Adapted from [119] 34 The presence of soluble NOM was reported to decrease the oxidation rate of several organic contaminants by ... addition of mg L-1 NOM decreased the oxidation rate of Triclosan by 14% and 61% for 15 mg L-1 NOM [63] The presence of 10 mg L-1 humic acid reduced the transformation rate of macrolides by MnO2 by...

Ngày tải lên: 10/04/2016, 08:39

... Symbols viii List of Tables xiii List of Figures xiv List of Schemes xvi xviii Publications PART-I: Mild Protection of Alcohols using Thiotetrazole Reagents Chapter 1 Mild Protection of Alcohols using ... Figure 3-4: LC-MS profile of a standard mixture of L and D amino acids………60 Figure 3-5: (a) LC-MS profile of the synthetic all L-version of the tetrapeptide (b) LC-MS profile of the natural peptide ... Center, Singapore xviii PART-I MILD PROTECTION OF ALCOHOLS USING THIOTETRAZOLE REAGENTS Chapter-1: Mild Protection of Alcohols using Thiotetrazole Reagents 1.1 Introduction-protecting groups Protecting...

Ngày tải lên: 11/09/2015, 10:02

... description of this reaction, along with a detailed analysis of the spectroscopic properties of the product of NADP+ oxidation Fig Hypothetical mechanism of the reductive half-reaction of the catalytic ... concentration of 500 lm was fully saturating The initial rate of NADPO formation promoted by AdR was slightly lower (75%) than that of FprA under the same conditions A peculiar feature of the NADP+ oxidation ... role of specific residues of FprA by site-directed mutagenesis On the basis of structural data, Glu214 and His57 of FprA have been proposed to be involved in promoting nucleophilic attack by a...

Ngày tải lên: 16/03/2014, 11:20

... indicated for the oxidation of N-hydroxyguanidines by one-electron oxidants and for the oxidation of benzamidoximes by H2O2 in the presence of HRP [15,37,38] In addition, the formation of intermediate ... after by the addition of catalase Analysis of the reaction mixtures by RP-HPLC using UV-detection revealed a signicant decrease of the amount of starting N-hydroxyguanidine and the formation of ... The oxidation of N-hydroxyguanidine and of NOHA by H2O2 catalysed by MP8 clearly involves an active species derived from the haem of MP8 as metal-free MP8 was inactive It also involves high oxidation...

Ngày tải lên: 17/03/2014, 09:20

... The radical mechanism of oxidation of a nonphenolic substrate by a laccase->N–OH mediator system [22], it has time to follow an analogous H-abstraction route of oxidation of the nonphenolic substrate ... resulting in an increase of charge transport and therefore of current intensity Effect of the pK2 of the mediator and of solution pH on the laccase-catalyzed oxidation of 4-methoxybenzylalcohol ... rapidly metabolized by the enzyme (undesired routes) In this study, we first investigated the kinetics of oxidation of phenol red by Poliporus pinsitus laccase in the absence of any mediator, and...

Ngày tải lên: 23/03/2014, 21:20

... demonstrated the growth of thin SiO2 layers with embedded metal and metal silicide NCs by the combination of Si:Me mixture by PLD at room temperature and its thermal oxidation By means of this fabrication ... during the oxidation of the Si:Me layer After the oxidation is completed, the sample is still kept at elevated temperature facilitating the coalescence of Me NCs The effect of the oxidation temperature ... http://www.nanoscalereslett.com/content/6/1/148 20 Page of SiPt SiAu 0 oxidation h, 640 oxidation h, 640 18 28 26 16 CSiO , pF oxidation h, 640 C oxidation h, 640 C 30 24 22 14 20 18 12 16 10 14 12...

Ngày tải lên: 21/06/2014, 05:20

... glucocorticoid, those of NF-kB and TNFa were at the same level as in the absence of glucocorticoid, those of IL-1b and IL-6 were higher than in the absence of glucocorticoid, and those of Cu/Zn-SOD, ... trophoblast cells induced by TNFa was also suppressed by this lower concentration of glucocorticoid [1] These previous results suggested that the expression of mRNA of inflammatory cytokines and/or ... activation of apoptosis is associated with ROS produced by mitochondria [27], that the generation of ROS in mitochondria was activated by TNFa [28] and that apoptosis could be blocked or delayed by antioxidants...

Ngày tải lên: 22/02/2014, 07:20

... in the oxidation reaction of glucose The conversion of the reaction reached 87.67% when using HNO3 as oxidizing agent, but the selectivity of D-gluconic product is quite low The high oxidation ... The pH value was maintained at and air flow was controlled by Flow Meter 110 AC device The products of the oxidation was determined by High performance liquid chromatography method (HPLC) with ... of Pt did not affect the hexagonal structure of SBA-15 support material [3] PS-3 PS-2 PS-1 Figure X-ray diffraction patterns of PS-1, PS-2 and PS-3 samples 186 T.T.N Mai et al / VNU Journal of...

Ngày tải lên: 05/03/2014, 11:21

... the quantification of the oxidation products The observed progressive inhibition of metformin oxidation, in the presence of added hydrogen peroxide, would come from the reaction of ÆOH radicals ... concentration of 0.1 molÆL)1 in order to convert all radicals (ÆOH, ÆH and e–aq) into O2Æ– radicals with a final G-value of 0.62 lmolÆJ)1 [20] Analysis Detection of the oxidation products was achieved by ... analyzed at 232 nm by absorption spectrophotometry The consumption of metformin was gradually decreased by increasing the concentration of H2O2 from 0.05 to mmolÆL)1 regardless of the radiation...

Ngày tải lên: 07/03/2014, 16:20

... is a mixture of these two Table Properties of the enzymatic steps/enzymes of the a -oxidation pathway The table gives an overview of the present knowledge of some of the properties of the enzymes ... peroxisomes [35] Table gives an overview of the presently known characteristics of the four main enzymes of the a -oxidation pathway Stereospecificity of the a -oxidation pathway Phytol has two chiral ... known as an inhibitor of catalase, had little effect on the conversion of 14C-formate to CO2 (but decreased the rates of a -oxidation by 90%) In rat formate is metabolized by two pathways: the...

Ngày tải lên: 08/03/2014, 02:20

... capsaicin significantly inhibited the oxidation of LDL, as indicated by TBARS values which were 71 and 62% of control rats Extent of iron-induced oxidation of LDL was considerably lower in curcumin ... determined by the colorimetric methods described by Bergmeyer and Bernt [28,29] Lactate dehydrogenase (LDH, EC.1.1.27) was assayed by the method of Kornberg [30] following the rate of oxidation of NADH ... volume of 10% trichloroacetic acid (TCA) followed by centrifugation To mL of the supernatant was added 300 mg of NaCl and 0.75 mL of butanol The supernatant was made alkaline by the addition of 0.1...

Ngày tải lên: 08/03/2014, 08:20

... in vitro reconstitution of the oxidation of propionyl-CoA to pyruvate by the use of purified PrpC, PrpD, AcnB and PrpB from E coli PrpD and AcnB involved in the conversion of methylcitrate into ... sequenced by Edman degradation (kindly performed by D Linder, Universitat Gießen, Germany) ¨ Re-activation and inactivation of AcnB AcnB was inactivated by exposure to air and by addition of either ... protein fractions by SDS/PAGE (Fig 2, lanes and 7) with an apparent molecular mass of 94 kDa and a turnover number of s)1 Comparison of the forward reaction (hydration of Determination of 2-methyl-cis-aconitate...

Ngày tải lên: 17/03/2014, 10:20

... (A) Magnitude of the peak current, Ip, for cysteine oxidation as a function of square root of scan rate and (B) peak potentials Ep of cysteine oxidation as a function of logarithm of scan rates ... a bundle of carbon fiber is composed of single fiber; (b) a bundle of carbon fiber is composed of 16 single fiber; (c) a bundle of carbon fiber is composed of 32 single fiber Sensors 2012, 12 ... Stability of Flow Cell-Voltammetric Sensor The operational stability of the sensors was studied by continuous exposure to the flow stream Figure 13 shows the stability of the sensor over 12 h of repetitive...

Ngày tải lên: 21/03/2014, 12:18

... oxynitrite-mediated oxidation of HPX (Table 2), reflects oxidation of the heme–Fe atom by CO3– rather than conformational transition(s) depending on the nitration of Tyr and Trp residues by NO2 As observed ... mechanism of the peroxynitrite-mediated oxidation of myoglobin in the absence and presence of carbon dioxide Chem Res Toxicol 16, 390–402 Boccini F & Herold S (2004) Mechanistic studies of the oxidation ... Ascenzi et al Pseudo-enzymatic properties of heme–hemopexin Fig Kinetics of peroxynitrite-mediated oxidation of HPX–heme(II)–NO in the absence and presence of CO2, at pH 7.0 and 10.0 °C (A) Steady-state...

Ngày tải lên: 23/03/2014, 10:20

... products, at rates of and 17 pmolÆmin)1Æmg)1 protein None of the products were identified In the study of Snider et al [11], the rates of production of anandamide oxidation products by human kidney ... Arachidonic acid formed trace amounts of 14,15- and 8,9-EETs but only in the presence of cytochrome b5 as an auxiliary factor The rates of oxidation of a number of other arachidonic acid derivatives, ... reactions were terminated by addition of two volumes of ethyl acetate and analyzed as described above Assay of cholesterol oxidation Assays of cholesterol oxidation were performed using a general...

Ngày tải lên: 30/03/2014, 04:20

... structure of about m height The surface of the structure consists of grayblack microbial mat; the interior of the massive mat is pink The greenish-gray inner part of the structure consists of porous ... formation of carbonate structures Epifluorescence microscopy of sections of microbial mat revealed dense aggregations of archaea and bacteria (Fig 2) (see SOM) The mats are penetrated by systems of ... from nearby sediment pockmarks is of biogenic origin, as indicated by ␦13C values of Ϫ62.4 to Ϫ68.3‰ (n ϭ 6) (SOM) and most probably evolves from a deeper sedimentary source Samples of living...

Ngày tải lên: 12/06/2014, 11:18

... investigate the effect of Mn precursors on the catalytic ozone oxidation of benzene Experimental details Synthesis of MnOx/Al-SBA-16 catalysts The detailed procedure for the synthesis of mesoporous silica ... types of poorly dispersed Mn oxides were formed by Mn nitrate On the basis of these results, it was expected that Al-SBA-16-MA15% would show a higher activity for the catalytic ozone oxidation of ... activity of Al-SBA-16-MA15% was higher than that of Al-SBA-16-MN15% It was shown that the type of precursors used for Mn impregnation influenced the dispersion, oxidation state, and oxygen mobility of...

Ngày tải lên: 20/06/2014, 23:20

... two different oxidation methods, photooxidation and basic oxidative treatment, for comparison Photooxidation was performed using UV radiation at a peak wavelength of 254 nm and power of 15 mW/cm ... 3c), and after 30 of treatment (Figure 3d), the nanostructures completely disappeared, as was observed after of photooxidation treatment (Figure 2d) The extent of the surface oxidation and hydroxyl ... samples oxidized by both treatments increased initially and then decreased at a time point when the surface was etched off In the case of UV photooxidation, a maximum contact angle of 109° ± 2° was...

Ngày tải lên: 20/06/2014, 23:20