- Phenyl glycosides – Solid-state NMR, X-ray diffraction and conformational analysis using genetic algorithm
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The X-ray structures of 2,6-dimethylphenyl and phenyl 2,3,4,6-tetra-O-acetyl β-glucosides (1 and 3) and phenyl α-mannoside (6) were obtained. The independent part of the unit cell of the glycosides 1 and 6 was formed by one molecule, and for the glucoside 3, two molecules in the crystal cell were observed. In deacetylated glycosides 4 and 6 the crystal structure was established by a hydrogen bond network formed between the sugar hydroxyls and solvent molecules. The 13C CPMAS NMR spectra of aryl glycosides 1–6 were analysed. In the spectrum of 3, doubling of the C4 aryl signal was observed which confirmed the presence of two independent molecules in the solid sample. The GAAGS (Genetic Algorithm-Assisted Grid Search) method was used to determine the low-energy conformers of α-mannosides and β-glucosides. The orientation of the aryl pendant group was calculated using Molecular Mechanics (MMFF94) as well as Quantum Mechanics theory (DFT, B3LYP/6-31 + G(d,p)).
- Wa?ejko, Piotr,Bukowicki, Jaros?aw,Dobrzycki, ?ukasz,Socha, Pawe?,Paradowska, Katarzyna
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p. 126 - 136
(2019/01/03)
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- Purification, characterization, and gene identification of an α-glucosyl transfer enzyme, a novel type α-glucosidase from Xanthomonas campestris WU-9701
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The α-glucosyl transfer enzyme (XgtA), a novel type α-glucosidase produced by Xanthomonas campestris WU-9701, was purified from the cell-free extract and characterized. The molecular weight of XgtA is estimated to be 57 kDa by SDS-PAGE and 60 kDa by gel filtration, indicating that XgtA is a monomeric enzyme. Kinetic properties of XgtA were determined for α-glucosyl transfer and maltose-hydrolyzing activities using maltose as the α-glucosyl donor, and if necessary, hydroquinone as the acceptor. The Vmax value for α-glucosyl transfer activity was 1.3 × 10-2 (mM/s); this value was 3.9-fold as much as that for maltose-hydrolyzing activity. XgtA neither produced maltooligosaccharides nor hydrolyzed sucrose. The gene encoding XgtA that contained a 1614-bp open reading frame was cloned, identified, and highly expressed in Escherichia coli JM109 as the host. Site-directed mutagenesis identified Asp201, Glu270, and Asp331 as the catalytic sites of XgtA, indicating that XgtA belongs to the glycoside hydrolase family 13.
- Sato, Toshiyuki,Hasegawa, Nobukazu,Saito, Jun,Umezawa, Satoru,Honda, Yuki,Kino, Kuniki,Kirimura, Kohtaro
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body text
p. 20 - 27
(2012/09/05)
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- COMPOUNDS AND METHODS FOR TREATING BACTERIAL INFECTIONS
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The present invention encompasses compounds and methods for treating urinary tract infections.
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Page/Page column 69-70
(2011/05/06)
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- FimH antagonists for the oral treatment of urinary tract infections: From design and synthesis to in vitro and in vivo evaluation
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Urinary tract infection (UTI) by uropathogenic Escherichia coli (UPEC) is one of the most common infections, particularly affecting women. The interaction of FimH, a lectin located at the tip of bacterial pili, with high mannose structures is critical for the ability of UPEC to colonize and invade the bladder epithelium. We describe the synthesis and the in vitro/in vivo evaluation of α-d-mannosides with the ability to block the bacteria/host cell interaction. According to the pharmacokinetic properties, a prodrug approach for their evaluation in the UTI mouse model was explored. As a result, an orally available, low molecular weight FimH antagonist was identified with the potential to reduce the colony forming units (CFU) in the urine by 2 orders of magnitude and in the bladder by 4 orders of magnitude. With FimH antagonist 16b, the great potential for the effective treatment of urinary tract infections with a new class of orally available antiinfectives could be demonstrated.
- Klein, Tobias,Abgottspon, Daniela,Wittwer, Matthias,Rabbani, Said,Herold, Janno,Jiang, Xiaohua,Kleeb, Simon,Lüthi, Christine,Scharenberg, Meike,Bezen?on, Jacqueline,Gubler, Erich,Pang, Lijuan,Smiesko, Martin,Cutting, Brian,Schwardt, Oliver,Ernst, Beat
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supporting information; experimental part
p. 8627 - 8641
(2011/02/28)
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- Selective electrochemical glycosylation by reactivity tuning
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Electrochemical glycosylation of a selenoglycoside donor proceeds efficiently in an undivided cell in acetonitrile to yield β-glycosides. Measurement of cyclic voltammograms for a selection of seleno-, thio-, and O-glycosides indicates the dependence of o
- France, Robert R.,Compton, Richard G.,Davis, Benjamin G.,Fairbanks, Antony J.,Rees, Neil V.,Wadhawan, Jay D.
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p. 2195 - 2202
(2007/10/03)
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- Regioselective Lipase-catalysed acylation of 4,6-O-benzylidene-α- and - β-D-pyranoside derivatives displaying a range of anomeric substituents
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The application of Lipase enzymes to effect regioselective C-3-O- acylation of 4,6-O-benzylidene-β-D-gluco- and -galactopyranosides displaying a range of anomeric substituents, and C-2-O-acylation of phenyl 4,6-O- benzylidene-α-D-glucopyranoside and ethyl 4,6-O-benzylidene-1-thio-α-D- glucopyranoside is reported. In particular this method has allowed introduction of a variety of acyl protecting groups at the C-3 hydroxyl group of ethyl 4,6-O-benzylidene-1-thio-β-D-glucopyranoside 11.
- Gridley, Jonathan J.,Hacking, Andrew J.,Osborn, Helen M. I.,Spackman, David G.
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p. 14925 - 14946
(2007/10/03)
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- Stannic chloride promoted synthesis of mannosides
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Use of anhyd.SnCl4 has been described for the synthesis of aryl, arylalkyl and alkyl α-D-mannopyranosides.A possible mechanism for the formation of α-anomer in these reactions is discussed.
- Irani, Rustom K,Sinha, Bharati,Bose, J L
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p. 519 - 521
(2007/10/02)
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- Solvolysis of D-Glucopyranosyl Derivatives in Mixtures of Ethanol and 2,2,2-Trifluoroethanol
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The products of solvolysis of α- and β-D-glucopyranosyl fluorides, 2,4-dinitrophenyl β-D-glucopyranoside, and the trifluoromethanesulfonates of the β-D-glucopyranosyl 3-bromopyridinium and α-D-glucopyranosyl 4-methylpyridinium ions in an equimolar mixture of ethanol and trifluoroethanol buffered with ca. 2 equiv of 2,6-lutidine have been examined by GLC of their trimethylsilyl ethers.The initial products of the solvolyses of phenyl α- and β-D-glucopyranosides catalyzed by trifluoromethanesulfonic acid in an equimolar mixture of ethanol and trifluoroethanol, and the products of uncatalyzed solvolysis of β-D-glucopyranosyl-p-nitrophenyltriazene, have been likewise examined.The composition of the medium for solvolysis of the glucosyl fluorides has also been systematically varied from pure ethanol to pure trifluoroethanol.The percentage of products with the same anomeric configuration as the starting material is in the range 8.1-88.5percent; change of leaving group, at constant anomeric configuration, or of anomeric configuration, at constant leaving group, yields different product distributions.Therefore the transition state for the product-determining step contains the leaving group.The preference for attack by ethanol as compared with trifluoroethanol varies from 0.9 to 20 in a way which shows no general systematic distinction between pathways for retention or inversion.The nucleophilic selectivity for retention is lowered by anionic leaving groups, especially fluoride, which preferentially stabilize the transition state containing trifluoroethanol by hydrogen bonding.Nucleophilic attack at the α face is preferred over nucleophilic attack at the β face, and exibits a lower selectivity: this is ascribed to hydrogen bonding between the oxygen atom of the 2-hydroxyl group and the hydroxyl group of the approaching alcohol.A model for solvolysis involving a reversibly formed ion pair or encounter complex is incompatible with the selectivities still observed with leaving groups less nucleophilic than the solvent components: a model involving selection between the components of a pool of solvent molecules by an irreversibly formed ion pair or encounter complex requires an implausibly large pool to explain observed specificities.It is therefore concluded that the observed selectivities are a consequence of the facilitation of the departure of the leaving group by the solvent, from either side of the reaction center.
- Sinnott, Michael L.,Jencks, William P.
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p. 2026 - 2032
(2007/10/02)
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