- Stereoselective Synthesis of 1,1′-Disaccharides by Organoboron Catalysis
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The highly stereoselective synthesis of 1,1′-disaccharides was achieved by using 1,2-dihydroxyglycosyl acceptors and glycosyl donors in the presence of a tricyclic borinic acid catalyst. In this reaction, the complexation of the diols and the catalyst is
- Izumi, Sanae,Kobayashi, Yusuke,Takemoto, Yoshiji
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p. 14054 - 14059
(2020/06/10)
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- Reagent controlled glycosylations for the assembly of well-defined pel oligosaccharides
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A new additive, methyl(phenyl)formamide (MPF), is introduced for the glycosylation of 2-azido-2-deoxyglucose building blocks. A linear α-(1,4)-glucosamine tetrasaccharide was assembled to prove the utility of MPF. Next, a hexasaccharide fragment of the Pseudomonas aeruginosa exopolysaccharide Pel was assembled using a [2 + 2 + 2] strategy modulated by MPF. The used [galactosazide-α-(1,4)-glucosazide] disaccharide building blocks were synthesized using a 4,6-O-DTBS protected galactosyl azide donor.
- Codeé, Jeroen D.C.,Wang, Liming,Zhang, Yongzhen,Overkleeft, Herman S.,van der Marel, Gijsbert A.
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p. 15872 - 15884
(2021/01/19)
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- Total Synthesis of the Congested, Bisphosphorylated Morganella morganii Zwitterionic Trisaccharide Repeating Unit
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Zwitterionic polysaccharides (ZPSs) activate T-cell-dependent immune responses by major histocompatibility complex class II presentation. Herein, we report the first synthesis of a Morganella morganii ZPS repeating unit as an enabling tool in the synthesis of novel ZPS materials. The repeating unit incorporates a 1,2-cis-α-glycosidic bond; the problematic 1,2-trans-galactosidic bond, Gal-β-(1 → 3)-GalNAc; and phosphoglycerol and phosphocholine residues which have not been previously observed together as functional groups on the same oligosaccharide. The successful third-generation approach leverages a first in class glycosylation of a phosphoglycerol-functionalized acceptor. To install the phosphocholine unit, a highly effective phosphocholine donor was synthesized.
- Keith, D. Jamin,Townsend, Steven D.
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p. 12939 - 12945
(2019/08/22)
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- Conversion of glycals into vicinal-1,2-diazides and 1,2-(or 2,1)-azidoacetates using hypervalent iodine reagents and Me3SiN3. Application in the synthesis of: N -glycopeptides, pseudo-trisaccharides and an iminosugar
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Glycals were found to react with a reagent system comprising of phenyliodine bis(trifluoroacetate) (PIFA) and Me3SiN3 in the presence of TMSOTf as a catalyst to form the corresponding vicinal 1,2-diazides. On the other hand, they rea
- Chennaiah, Ande,Bhowmick, Srijita,Vankar, Yashwant D.
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p. 41755 - 41762
(2017/09/08)
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- Direct, microwave-assisted substitution of anomeric nitrate-esters
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A series of carbohydrate 2-azido-1-nitrate-esters, protected at the C-3, C-4, and C-6 positions, were hydrolyzed thermally under reagent free conditions. This preliminary result was extended to direct exchange of the 1-nitrate-ester modality for alcohol,
- Keith, D. Jamin,Townsend, Steven D.
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supporting information
p. 20 - 24
(2017/03/11)
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- Study of the stereoselectivity of 2-azido-2-deoxygalactosyl donors: Remote protecting group effects and temperature dependency
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The stereoselectivity of glycosylation reactions is affected by many factors. Synthesis of 1,2-cis glycosidic linkages (such as α linkages in glucose and galactose like monosaccharides) is challenging due to lack of control of the stereoselectivity. Our s
- Kalikanda, Jane,Li, Zhitao
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p. 5207 - 5218
(2011/08/09)
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- Glycosylation using 2-azido-3,4,6-tri-O-benzyl-2-deoxy-D-glucose, - galactose, and -mannose with the aid of p-nitrobenzenesulfonyl chloride- silver trifluoromethanesulfonate-triethylamine system
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This report describes a simple synthesis of 2-azido-3,4,6-tri-O-benzyl- 2-deoxy-D-glucopyranose. Glycosylation using this as well as 2-azido-3,4,6- tri-O-benzyl-2-deoxy-D-galactopyranose and -mannopyranose was achieved with the aid of a reagent system consisting of p-nitrobenzenesulfonyl chloride, silver trifluoromethanesulfonate, and triethylamine, and its modifications. O-(2-Acetamido-2-deoxy-β-D-glucopyranosyl)-(1 → 4)-O-α-D-mannopyranosyl- (1 → 4)-a-D-mannopyranose, the repeating unit of the main chain of the O- specific cell wall polysaccharide of E. coli 058 was synthesized.
- Koto, Shinkiti,Asami, Kazuyasu,Hirooka, Motoko,Nagura, Kazuo,Takizawa, Mizue,Yamamoto, Satoko,Okamoto, Nami,Sato, Mitsuko,Tajima, Hiromi,Yoshida, Toyosaku,Nonaka, Nobuo,Sato, Tadaaki,Zen, Shonosuke,Yago, Kazuo,Tomonaga, Fumiya
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p. 765 - 777
(2007/10/03)
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- Synthesis of some amino and carboxy analogs of galabiose; evaluation as inhibitors of the pilus protein PapG(J)96 from Escherichia coli
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The 2'-amino-2'-deoxy, 6-amino-6-deoxy, and 6-carboxy analogs of the reference inhibitor 2(trimethylsilyl)ethyl (α-D-galactopyranosyl)-(1→4)- β-d-galactopyranoside were synthesized and evaluated as inhibitors of the binding of the Escherichia coli-derived pilus protein PapG(J96), using an ELISA assay. The inhibitory efficiencies (K(rel); relative to the reference inhibitor) were: 157, 13, and 8, respectively. The results support the previously proposed combining site model, where the protein carries a negatively charged amino acid residue near HO-2' and HO-6 of the galabioside.
- Hansen, Henrik C.,Magnusson, Goeran
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p. 233 - 242
(2007/10/03)
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- Electrophilic Azidation of 2-Deoxy-aldono-1,5-lactones: an Alternative Route to 2-Azido-2-deoxy-aldopyranoses
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Electrophilic azidation of tri-O-benzyl-2-deoxy-D-galactono-1,5-lactone 3 with triisopropylphenylsulfonyl azide, followed by selective reduction with diisobutylaluminium hydride, yielded tri-O-benzyl-2-azido-2-deoxy-D-galactopyranose 5 as the sole product
- Dupradeau, Francois-Yves,Hakomori, Sen-itiroh,Toyokuni, Tatsushi
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p. 221 - 222
(2007/10/02)
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- Preparation of diversely protected 2-azido-2-deoxyglycopyranoses from glycals
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A new and efficient preparation of diversely protected 2-azido-2-deoxyglycopyranosides from the corresponding glycals is described. The glycals are first transformed into protected phenyl 2-azido-2-deoxy-selenoglycopyranosides by azido-phenylselenylation.
- Czernecki,Ayadi
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p. 343 - 350
(2007/10/03)
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- New and Efficient Synthesis of Protected 2-Azido-2-deoxy-glycopyranoses from the Corresponding Glycal
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Diversely protected 2-azido-2-deoxy-D-glycopyranoses are prepared by azido phenylselenylation of the corresponding glycal followed by hydrolysis of the resulting selenoglycosides: from protected D-galactal, protected 2-azido-2-deoxy-D-galactopyranose is obtained, as the sole product in 72percent overall yield.
- Czernecki, Stanislas,Ayadi, Ebtissam,Randriamandimby, Dominique
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- Glycosylphosphonates of 2-Amino-2-deoxy-aldoses. Synthesis of a Phosphonate Analogue of Lipid X
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A preparation of glycosylphosphonates (27, 28, 36, 38, and 39) from 2-azido-2-deoxy-glycoses (26, 35, and 37) and the synthesis of the non-isosteric phosphonate analogue 3a of lipid X (2) are described.The 2-azido group was introduced by azidonitration.Tr
- Briner, Karin,Vasella, Andrea
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p. 1341 - 1356
(2007/10/02)
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- SYNTHESE DER TETRA- UND TRISACCHARID-SEQUENZEN VON ASIALO-GM1 UND -GM2. LENKUNG DER REGIOSELEKTIVITAET DER GLYCOSIDIERUNG VON LACTOSE
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A regioselective β-glycosidation of lactose derivatives unsubstituted at OH-3' and -4' is possible, depending on the catalyst system applied.With silver silicate or silver carbonate as catalyst under hetrogeneous conditions, β-glycosidation occured selectively at the less reactive OH-4'group of the acceptor, whereas with trimethylsilyl triflate or soluble mercury salt as catalyst under homogeneous conditions, it occured almost exclusively at the more reactive OH-3' group.The reactivity of the glycosyl donor, acceptor, and catalyst had to be properly matched for successful regioselective coupling.In this way, the trisaccharide unit of asialo-GM2-ganglioside, O-(2-acetamido-2-deoxy-β-D-galactopyranosyl)-(1--4)-(β-D-galactopyranosyl-(1--4)-D-glucopyranose, and the tetrasaccharide unit of asialo-GM1-ganglioside, O-(β-D-galactopyranosyl)-(1--3)-(2-acetamido-2-deoxy-β-D-galactopyranosyl)-(1--4)-(β-D-galactopyranosyl)-(1--4)-β-D-glucopyranose were synthesized.This new method constitutes a very useful approach in the field of ganglioside synthesis.
- Paulsen, Hans,Paal, Michael
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- Glycosyl Imidates 13. - Application of the Trichloroacetimidate Procedure to 2-Azidoglucose and 2-Azidogalactose Derivatives
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Base-catalyzed addition of 1-O-unsubstituted 2-azidohexoses to trichloroacetonitrile led to the corresponding O-glycosyl trichloroacetimidates.Depending on the base used α- and β-trichloroacetimidates of 2-azidogalactosyl, 2-azidoglucosyl, and 2-azidolact
- Grundler, Gerhard,Schmidt, Richard R.
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p. 1826 - 1847
(2007/10/02)
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