نتایج جستجو برای: anomeric based oxidation

تعداد نتایج: 3036890  

2007
Marek Chmielewski Birgit Sauerzapfe Peter Gasteier Karel Krenek Warren W. Wakarchuk Vladimir Kren Martin Möller Lothar Elling

Some time ago we reported the oxidation of 2,3-unsaturated hexopyranosides and 2-Cmethylene glycosides with hydrogen peroxide in the presence of molybdenum trioxide catalyst to give the corresponding anomeric hydroperoxides 1-5. Relatively stable hydroperoxides 1-5 were used for enantioselective oxidation of prochiral alcohols and sulfides in the presence of Ti(OiPr)4 with stereoselectivities v...

Journal: :The Journal of organic chemistry 2016
Varsha R Jumde Niek N H M Eisink Martin D Witte Adriaan J Minnaard

Palladium-catalyzed oxidation can single out the secondary hydroxyl group at C3 in glucose, circumventing the more readily accessible hydroxyl at C6 and the more reactive anomeric hydroxyl. Oxidation followed by reduction results in either allose or allitol, each a rare sugar that is important in biotechnology. Also, N-acetylglucosamine is selectively oxidized at C3. These results demonstrate t...

Nea Hasanzadeh Raja Ahmadzadeh

NBO analysis, hybrid density functional theory (B3LYP/6-311+G**) based methods were used to study the anomeric effects (AE), Stereoelectronic interactions, dipole-dipole interactions on the conformational properties of 1-Fluoro-N, N-dimethylmethanamine (1) and phosphorus (2) and arsenic (3) analogues.Moreover, relationships between stability of the anti-conformations of 1-Fluoro-N, N-dimethylme...

Journal: :Physical chemistry chemical physics : PCCP 2010
Fernando Cortés-Guzmán Jesús Hernández-Trujillo Gabriel Cuevas

The conformational preference in normal and reverse anomeric effects is analyzed by taking advantage of the known additivity and transferability of functional group energies defined by the gradient of the electron density. As the anomeric effect has an energetic origin and every change in the electron density produces an energetic change, an explanation of this phenomenon should be based on the...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد یزد - دانشکده شیمی 1392

in this study, a simple, rapid and selective method was developed for the determination of dexamethasone. the proposed method is based on inhibitory effect of dexamethasone on the oxidation of orange-g by bromate in sulfuric acid media. the reaction was followed spectrophotometrically at 478.5 nm (?max). under optimum experimental conditions, (72.6 ?mol l-1 of orange-g, 0.76 mol l-1 of h2so4, 0...

2015
Patricia Wildberger Martin Pfeiffer Lothar Brecker Bernd Nidetzky

Sugar phosphates play an important role in metabolism and signaling, but also as constituents of macromolecular structures. Selective phosphorylation of sugars is chemically difficult, particularly at the anomeric center. We report phosphatase-catalyzed diastereoselective "anomeric" phosphorylation of various aldose substrates with α-D-glucose 1-phosphate, derived from phosphorylase-catalyzed c...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1389

fluorescence chemical sensors for the highly sensitive and selective determination of pb2+ , hg2+, co2+ and fe3+ ions in aqueous solutions are described. the ion sensing system was prepared by incorporating lipophilic ligand (l) as a neutral ion-selective fluoroionophore in the plasticized pvc membrane containing sodium tetraphenylborate or potasium tetrakis (p-chlorophenyl) borate as a liphoph...

2005
JAMES BADDILEY

The well-known immologically active component of pneumococci, C-polysaccharide, is a teichoic acid that can be isolated from the cell walls and purified by Sephadex and ionexchange chromatography. Further details of the structure of C-teichoic acid were established by chemical degradation, including hydrolysis in acid and alkali, treatment with HF, periodate oxidation and methylation. In additi...

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