- Enantioselective and protecting group-free synthesis of 1-deoxythionojirimycin, 1-deoxythiomannojirimycin, and 1- deoxythiotalonojirimycin
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1-Deoxythioglyconojirimycins were synthesized by using a protecting group-free strategy, starting from readily available carbohydrates, in good overall yield. Use of benzyltriethylammonium tetrathiomolybdate, [BnEt 3N]2MoS4, as a sulfur transfer reagent and borohydride exchange resin (BER) reduction of a lactone enabled the efficient synthesis of the title compounds.
- Gunasundari, Thanikachalam,Chandrasekaran, Srinivasan
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supporting information; experimental part
p. 6685 - 6688
(2010/12/25)
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- Solubilization, purification, and properties of membrane-bound D-glucono-δ-lactone hydrolase from Gluconobacter oxydans
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Membrane-bound glucono-δ-lactonase (MGL) was purified to homogeneity from the membrane fraction of Gluconobacter oxydans IFO 3244. After solubilization with 1 M CaCl2, MGL was purified in the presence of Ca2+ and detergent. A single
- Shinagawa, Emiko,Ano, Yoshitaka,Yakushi, Toshiharu,Adachi, Osao,Matsushita, Kazunobu
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body text
p. 241 - 244
(2009/06/20)
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- Redox behaviour of chromium(VI) towards D-mannose in the presence and absence of micelles and inorganic salts
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The kinetics and mechanism of the oxidation of D-mannose by chromium(VI) in the absence and presence of sodium dodecyl sulfate(SDS) and polyoxylethylene t-octylphenol(TX-100) micelles have been investigated. Under pseudo-first-order conditions the reaction rate is of fractional- and first-order, respectively, in D-mannose and oxidant. The reaction is catalyzed by the micelles which is due to favourable electrostatic/thermodynamic/hydrophobic/hydrogen bonding between the reactants and anionic/nonionic micelles. From the observed kinetic data micelle-chromium(VI) binding constants(KS) and micelle-D-mannose binding constants(KM) were calculated to be 86, 84 mol-1 dm3 and 58, 75 mol-1 dm3 for SDS and TX-100, respectively. The reaction is retarded by addition of inorganic salts (NaBr, LiBr, NH4Br) which is attributed to competition between salt cations and H+ from the reaction sites in the SDS micelles.
- Kabir-Ud-Din,Morshed, Abu Mohanunad Azmal,Khan, Zaheer
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p. 2178 - 2188
(2007/10/03)
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- δ-Galactonolactone: Synthesis, isolation, and comparative structure and stability analysis of an elusive sugar derivative
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δ-D-Gluconolactone, δ-D-mannonolactone, and - for the first time - the thermodynamically unstable δ-D-galactonolactone have been prepared and isolated from DMF solution by oxidizing the corresponding sugars with Shvo's catalyst [(C4Ph4CO)(CO)2Ru] 2 and a hydrogen acceptor. The preferred conformation of δ-D-galactonolactone in [D6] DMSO solution has been determined by 1H NMR spectroscopy experiments and DFT calculations to be 4H3 and is compared to those of the previously established conformations of δ-D-gluconolactone (4H3) and δ-D-mannonolactone (B2,5), The conformations of the lactones suggest an explanation for their relative rates of isomerization to their respective γ-D-lactones by an intramolecular mechanism. Wiley-VCH Verlag GmbH & Co, KGaA, 69451 Weinheim, Germany, 2004.
- Bierenstiel, Matthias,Schlaf, Marcel
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p. 1474 - 1481
(2007/10/03)
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- Kinetics of Ru(III) Catalysed Oxidation of Aldoses by N-Bromosuccinimide in Aqueous Acetic Acid
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The title reaction, studied in the presence of mercuric acetate, sulphuric acid and 10percent (v/v) acetic acid, is first order in both in the presence and absence of catalyst.However, the order in in the absence of catalyst, Ru(III) is unity which changes to fractional order in the presence of it.Increase in retards the reaction rate.The order of reactivities of different aldoses is: D-arabinose > D-xylose > D-galactose > D-mannose > D-glucose.Individual rate constants (k), formation constants (K) of the complex of aldoses and the catalyst and corresponding thermodynamic parameters have been evaluated and a suitable mechanism involving the α-anomer of aldose as the reactive substrate species has been suggested.
- Kistayya, T.,Reddy, M. Surekha,Kandlikar, Sushama
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p. 905 - 907
(2007/10/02)
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