- Synthesis of stigmasteryl (β1→4)-oligoglucosides
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Stigmasteryl (β1→4)-oligoglucosides were prepared with cellobiose, cellotriose, and cellotetraose as glycan chains. For the preparation of the peracetylated oligoglucosyl donors anomeric acetate was deprotected and the respective hemiacetals were converted into trichloroacetimidates. Glycosylation with stigmasterol yielded both α-and β-anomers because during the treatment with Lewis acid the 2-OAc is cleaved to some extent; thus, with the emerging hydroxyl group neighboring group participation does not take place. Due to their different number of hydroxyl groups (0 vs. 1) separation of the two products proved to be facile. Saponification led to the desired stigmasteryl glucosides.
- Kettelhoit, Katharina,Werz, Daniel B.
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- Isolation, modification, and NMR assignments of a series of cellulose oligomers
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A homologous series of cellulose oligomers from two to eight repeating subunits have been isolated and size-fractionated from the hydrolysis products of microcrystalline cellulose. Chemical modification of cellotriose (1), cellotetraose (2), cellopentaose (3), and cellohexaose (4) to the corresponding β-methyl glycosides 13-16 proceeded in three steps in overall yields of 16-46%. Peracetylation produced oligomers 5-8 in 70-75% yield, and subsequent formation of the β-methyl glycosides gave 9-12 in 42-89% yield. Removal of the acetate-protecting groups employing guanidine provided 13-16 in 73-79% yield. This modification eliminated anomeric equilibration and permitted a detailed NMR solution study of these oligomers. The complete 1H and 13C chemical shift assignments of each peracetylated and deprotected oligomer were obtained through a combination of DQF-COSY, HMQC, HMBC, and HMQC-TOCSY experiments. All the resonances in methyl cellotriose (13) and methyl cellotetraose (14) were readily distinguishable from one another and directly assignable. Severe overlap of the resonances for the inner pyranose rings of methyl cellopentaose (15) and methyl cellohexaose (16) was observed and could only be resolved and assigned using a comprehensive battery of 3D pulse sequences. These results demonstrate the utility of multidimensional NMR experiments in assigning the signals from a repeating polysaccharide and represent the first necessary step in a comprehensive, systematic study of cellulose oligomers in solution.
- Flugge, Lisa A.,Blank, Jarred T.,Petillo, Peter A.
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- Design, synthesis of oleanolic acid-saccharide conjugates using click chemistry methodology and study of their anti-influenza activity
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The development of entry inhibitors is an emerging approach to the inhibition of influenza virus. In our previous research, oleanolic acid (OA) was discovered as a mild influenza hemagglutinin (HA) inhibitor. Herein, as a further study, we report the preparation of a series of OA-saccharide conjugates via the CuAAC reaction, and the anti-influenza activity of these compounds was evaluated in vitro. Among them, compound 11b, an OA-glucose conjugate, showed a significantly increased anti-influenza activity with an IC50 of 5.47 μM, and no obvious cytotoxic effect on MDCK cells was observed at 100 μM. Hemagglutination inhibition assay and docking experiment indicated that 11b might interfere with influenza virus infection by acting on HA protein. Broad-spectrum anti-influenza experiments showed 11b to be robustly potent against 5 different strains, including influenza A and B viruses, with IC50 values at the low-micromole level. Overall, this finding further extends the utility of OA-saccharide conjugates in anti-influenza virus drug design.
- Su, Yangqing,Meng, Lingkuan,Sun, Jiaqi,Li, Weijia,Shao, Liang,Chen, Kexuan,Zhou, Demin,Yang, Fan,Yu, Fei
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- Saccharide-functionalized alkanethiols for fouling-resistant self-assembled monolayers: Synthesis, monolayer properties, and antifouling behavior
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We describe the synthesis of a series of mono-, di-, and trisaccharide-functionalized alkanethiols as well as the formation of fouling-resistant self-assembled monolayers (SAMs) from these. The SAMs were characterized using ellipsometry, wetting measurements, and infrared reflection-absorption spectroscopy (IRAS). We show that the structure of the carbohydrate moiety affects the packing density and that this also alters the alkane chain organization. Upon increasing the size of the sugar moieties (from mono- to di- and trisaccharides), the structural qualities of the monolayers deteriorated with increasing disorder, and for the trisaccharide, slow reorganization dynamics in response to changes in the environmental polarity were observed. The antifouling properties of these SAMs were investigated through protein adsorption experiments from buffer solutions as well as settlement (attachment) tests using two common marine fouling species, zoospores of the green macroalga Ulva linza and cypris larvae of the barnacle Balanus amphitrite. The SAMs showed overall good resistance to fouling by both the proteins and the tested marine organisms. To improve the packing density of the SAMs with bulky headgroups, we employed mixed SAMs where the saccharide-thiols are diluted with a filler molecule having a small 2-hydroxyethyl headgroup. This method also provides a means by which the steric availability of sugar moieties can be varied, which is of interest for specific interaction studies with surface-bound sugars. The results of the surface dilution study and the low nonspecific adsorption onto the SAMs both indicate the feasibility of this approach.
- Fyrner, Timmy,Lee, Hung-Hsun,Mangone, Alberto,Ekblad, Tobias,Pettitt, Michala E.,Callow, Maureen E.,Callow, James A.,Conlan, Sheelagh L.,Mutton, Robert,Clare, Anthony S.,Konradsson, Peter,Liedberg, Bo,Ederth, Thomas
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experimental part
p. 15034 - 15047
(2012/04/10)
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- Photocleavable molecule for laser desorption ionization mass spectrometry
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(Figure Presented) A new photocleavable molecule for laser desorption ionization mass spectrometry (LDI-MS) was designed and synthesized. The molecule exhibited high sensitivity for negative mode MS detection with good chemical stability. The molecule was successfully applied to molecular tag for (LDI-MS). Kinetic measurement of the amidation reaction and monitoring of aminolysis of acetylated sugars were demonstrated with the molecular tag.
- Maki, Toshihide,Ishida, Koji
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p. 6427 - 6433
(2008/02/10)
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- Saccharide-coated M12L24 molecular spheres that form aggregates by multi-interaction with proteins
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The self-assembly of saccharide-coated nanometer-sized molecular spheres is reported, where 24 (oligo)saccharides are precisely arrayed at the periphery of the spherical core. When combined with lectins, they form aggregates because of the cluster effect of the saccharides on the spheres. Copyright
- Kamiya, Nozomi,Tominaga, Masahide,Sato, Sota,Fujita, Makoto
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p. 3816 - 3817
(2008/02/03)
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- REAGENTS AND METHODS FOR THE FORMATION OF DISULFIDE BONDS AND THE GLYCOSYLATION OF PROTEINS
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Methods and reagents for the formation of disulfide bonds, particularly in proteins, peptides and amino acids. The methods and reagents are particularly useful for the controlled glycosylation of proteins, peptides and amino acids. The methods utilise thiosulfonate or selenenylsulfide compounds as reagents or intermediates. Some proteins and peptides comprising selenenylsulfide groups also form part of the invention.
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Page/Page column 24-25
(2010/02/10)
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- A programmable one-pot oligosaccharide synthesis for diversifying the sugar domains of natural products: A case study of vancomycin
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The notoriously difficult glycosylation of vancomycin was tackled in a one-pot procedure. A number of oligosaccharides were synthesized and attached to the vancomycin aglycon to create a library of derivatives (see formula) to probe the effect of glycosylation on the antibiotic activity.
- Ritter, Thomas K.,Mong, Kwok-Kong T.,Liu, Haitian,Nakatani, Takuji,Wong, Chi-Huey
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p. 4657 - 4660
(2007/10/03)
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- Glycosyl phenylthiosulfonates (glyco-PTS): novel reagents for glycoprotein synthesis.
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Controlled site-selective glycosylation can be achieved by combining site-directed cysteine mutagenesis with chemical modification of the introduced thiol; a new class of more efficient chemoselective reagents, glycosyl phenylthiosulfonates, allow rapid glycosylations of representative simple thiols, peptides and proteins.
- Gamblin, David P,Garnier, Philippe,Ward, Sarah J,Oldham, Neil J,Fairbanks, Antony J,Davis, Benjamin G
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p. 3642 - 3644
(2007/10/03)
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- A short route to malto-trisaccharide synthons: Synthesis of the branched nonasaccharide, 6?-α-maltotriosyl-maltohexaose
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A short route to phenyl 1-thio-β-maltotrioside derived building blocks and their use for the synthesis of the branched nonasaccharide, 6?-α-maltotriosyl-maltohexaose, is described. Instead of using glucose and maltose as starting materials, maltotriose wa
- Damager, Iben,Olsen, Carl Erik,Lindberg M?ller, Birger,Motawia, Mohammed Saddik
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p. 418 - 426
(2007/10/03)
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- Synthesis of α-tocopheryl oligosaccharides
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As effective natural antioxidants, tocopherols and also their esters are frequently added to foodstuffs, pharmaceuticals and cosmetics. For increase of polarity, hence solubility in water, a series of α-tocopheryl oligosaccharides was synthesised using BF3-etherate. The pure α-tocopheryl β-maltotetraoside as well as the higher homologues proved to be water-soluble.
- Lahmann, Martina,Thiem, Joachim
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- Synthesis of Glucose-Containing Linear Oligosaccharides Having α(1->4) and α(1->6) Linkages Using Stereoselective Dehydrative Glycosylation
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Glycogen-storage-disease-relating linear tetra-, hexa-, and octasaccharides of D-glucose having α(1->4) and α(1->6) linkages were synthesized using a stereoselective dehydrative glycosylation with a reagent mixture of p-nitrobenzenesulfonyl chloride, silver trifluoromethanesulfonate, N,N-dimethylacetamide, and triethylamine.A cross-condensation of a quasi-stoichiometric amount of a donor and an acceptor of an octasaccheride, followed by deprotection, afforded a glucohexadecasaccharide.
- Koto, Shinkiti,Haigoh, Hisamitsu,Shichi, Sonoko,Hirooka, Motoko,Nakamura, Teiko,et al.
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p. 2331 - 2348
(2007/10/03)
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- Synthesis of 1,3-di-O-alkyl-2-O-(β-glycosyl)glycerols bearing oligosaccharides as hydrophilic groups
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A novel series of synthetic glycolipids, 1,3-di-O-alkyl-2-O-(β-glycosyl)glycerols, and their efficient synthetic route were proposed.These glyceroglycolipids were synthesized in good overall yields and stereoselectivity in five steps via trichloroacetimidate glycosylation with 1,3-di-O-alkylglycerols.This route was applied to prepare the glycolipids bearing a cello- or malto-oligosaccharide with a definite number of sugar residues from one to six.Thin-layer chromatography, elemental analysis, nuclear magnetic resonance spectroscopy and infrared absorption spectroscopy confirmed that these glycolipids were chemically pure compounds.Keywords: Glyceroglycolipids; Oligosaccharide headgroups; Synthesis
- Minamikawa, Hiroyuki,Murakami, Teiichi,Hato, Masakatsu
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p. 111 - 118
(2007/10/02)
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- 1,6-ANHYDRO-β-MALTOTRIOSE: PREPARATION FROM PULLULAN, AND REGIOSELECTIVE PARTIAL-PROTECTION REACTIONS
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1,6-Anhydro-β-maltotriose (4) was prepared from the microbial polysaccharide pullulan in 33percent overall yield by a combination of enzymic degradation and subsequent chemical treatments.Reaction of 4 with α,α-dimethoxytoluene and with 2,2-dimethoxypropa
- Sakairi, Nobuo,Hayashida, Mitsuo,Kuzuhara, Hiroyoshi
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