- Mannose-binding geometry of pradimicin A
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Pradimicins (PRMs) and benanomicins are the only family of non-peptidic natural products with lectin-like properties, that is, they recognize D-mannopyranoside (Man) in the presence of Ca2+ ions. Coupled with their unique Man binding ability, t
- Nakagawa, Yu,Doi, Takashi,Taketani, Takara,Takegoshi,Igarashi, Yasuhiro,Ito, Yukishige
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supporting information
p. 10516 - 10525
(2013/08/23)
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- β-Rhamnosides from 6-thio mannosides
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Upon condensation of 6-thio-6-deoxy-mannosyl donors 1,2-cis products are obtained with a high degree of stereoselectivity. Subsequent reductive removal of the 6-thio functionality gives 1,2-cis rhamnosides. The 1,2-cis-selectivity can be rationalized with
- Christina, Alphert E.,Es, Daan Van Der,Dinkelaar, Jasper,Overkleeft, Hermen S.,Marel, Gijsbert A. Van Der,Codee, Jeroen D. C.
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supporting information; experimental part
p. 2686 - 2688
(2012/04/10)
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- Rapid assembly of gp120 oligosaccharide moieties via one-pot glycosidation-deprotection sequences
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Mannosyl trihaloacetimidate donors equipped with a 2-O-Fmoc group can be effectively activated by catalytic Bi(OTf)3 in glycosidations. Despite the expected participating effect of the Fmoc group, the reaction solvent was found to be decisive f
- Pastore, Antonello,Adinolfi, Matteo,Iadonisi, Alfonso,Valerio, Silvia
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experimental part
p. 1316 - 1323
(2010/10/02)
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- Synthesis of novel mannose-based crown ethers
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A novel class of chiral crown ether analogues incorporating carbohydrate subunits can be easily prepared from methyl α-D-mannopyranoside. By a short reaction sequence involving either alkylations using a dibutylstannane intermediate or by phase transfer c
- Rathjens,Thiem
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p. 211 - 222
(2007/10/03)
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- Efficient synthesis of man2, man3, and man 5 oligosaccharides, using mannosyl iodide donors
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A highly efficient protocol for making Man3 and Man5 oligosaccharides with use of orthogonally protected glycosyl iodide donors has been developed. Glycosylation of a C-2-O-acetyl mannosyl iodide donor in the presence of silver trifl
- Lam, Son N.,Gervay-Hague, Jacquelyn
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p. 8772 - 8779
(2007/10/03)
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- Borane/Bu2BOTf: A mild reagent for the regioselective reductive ring opening of benzylidene acetals in carbohydrates
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BH3/Bu2OTf is an effective reagent to reductively cleave 4,6-O-benzylidene acetals of various hexopyranosides to the corresponding 4-O-benzyl ethers. 4,6-O-Isopropylidene acetals can be similarly cleaved. Common protecting groups are
- Jiang, Lu,Chan, Tak-Hang
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p. 355 - 358
(2007/10/03)
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- Chemistry of 1-alkoxy-1-glycosyl radicals: The manno- and rhamnopyranosyl series. Inversion of α- to β-pyranosides and the fragmentation of anomeric radicals
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The formation and stereoselective quenching of 1-mannopyranosyl radicals by a tributyltin hydride-mediated intramolecular 1,5-hydrogen abstraction sequence is described. A competing process is 1,4-hydrogen atom abstraction leading principally to glucopyran-2-ulosides. Fragmentation of the anomeric radical resulting in the formation of ring opened products is a problem in certain series. The chemistry is dictated to a considerable extent by the nature of the protecting groups employed with the 4,6-benzylidene series and, for rhamnose, the Ley 3,4-dispiroketal, being particularly susceptible to the 1,4-hydrogen atom abstraction but less to the fragmentation. Photochemical conditions are described, in which these side reactions are practically eliminated, and applied to the inversion of an α- to a β-mannoside in a disaccharide.
- Crich, David,Sun, Sanxing,Brunckova, Jarmila
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p. 605 - 615
(2007/10/03)
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- Control of glycoprotein synthesis. Characterization of (1->4)-N-acetyl-β-D-glucosaminyltransferases acting on the α-D-(1->3)- and α-D-(1->6)-linked arms of N-linked oligosaccharides
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Hen oviduct membranes contain at least three N-acetyl-β-D-glucosaminyltransferases (GlcNAc-T) that attach a βGlcNAc residue in (1-4)-linkage to a D-Manp residue of the N-linked oligosaccharide core, i.e., (1->4)-β-D-GlcNAc-T III which adds a "bisecting " GlcNAc group to form the β-D-GlcpNAc-(1->4)-β-D-Manp-(1->4)-D-GlcNAc moiety: (1->2)-β-D-GlcNAc-T IV which adds a GlcNAc group to the (1->3)-α-D-Man arm to form the β-D-GlcpNAc-(1->4)-2)>-α-D-Manp-(1->3)-β-D-Manp-(1->4)-D-GlcpNAc component; and (1->4)-β-D-GlcNAc-T VI which adds a GlcNAc group to the α-D-Manp residue of β-D-GlcpNAc-(1->6)-2)>-α-D-Manp-R to form β-D-GlcpNAc-(1->6)-4)>-2)>-α-D-Manp-R.We now report a novel (1->4)-β-D-GlcNAc-T activity (GlcNAc-T VI') in hen oviduct membranes that transfers GlcNAc to β-D-GlcpNAc-(1->2)-α-D-Manp-(1->6)-β-D-Manp-R to form β-D-GlcpNAc-(1->4)-2)>-α-D-Manp-(1->6)-β-D-Manp-R.The structure of the enzyme product was confirmed by 1H NMR spectroscopy.FAB-mass spectrometry and methylation analysis.Previous work with GlcNAc-T IV was carried out with biantennary substrates; we now show that hen oviduct membrane GlcNAc-T IV can also transfer GlcNAc to monoantennary β-D-GlcpNAc-(1->2)-α-D-Manp-(1->3)-β-D-Manp-R to form β-D-GlcpNAc-(1->4)-2)>-α-D-Man-p-(1->3)-β-D-Manp-R.The findings that GlcNAc-T VI'and IV have similar kinetic characteristics and that hen oviduct membranes can convert methyl β-D-GlcpNAc-(1->2)-α-D-Manp to methyl β-D-GlcpNAc-(1->4)-2)>-α-D-Manp suggest that these two activities may be due to the same enzyme.The R-group of the β-D-GlcpNAc-(1->2)-α-D-Manp-(1->6)-β-D-Manp (or Glcp)-R substrate has an important influence on GlcNAc-T VI'enzyme activity.When R is GlcNAc or βGlc-ally, the activity is drastically reduced.This may be due to conformational factors and may explain why hen oviduct membranes add a GlcNAc residue in (1->4)-β-linkage mainly to the (1->3)-α-D-Man arm of the bi-antennary substrate β-D-GlcpNAc-(1->2)-α-D-Manp-(1->6)-2)-α-D-Manp-(1->3)>-β-D-Manp-R to form β-D-GlcpNAc-(1->2)-α-D-Manp-(1->6)-2)-4)>-α-D-Manp-(1->3)>-β-D-Manp-R.
- Brockhausen, Inka,Moeller, Gabriele,Yang, Ji-Mao,Khan, Shaheer H.,Matta, Khushi L.,et al.
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p. 281 - 300
(2007/10/02)
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- SYNTHESIS OF EVERNINOSE, A NON-REDUCING DISACCHARIDE COMPONENT OF THE ORTHOSOMYCIN-TYPE OLIGOSACCHARIDE ANTIBIOTICS
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Glycosylation of 3,4-di-O-benzyl-2-O-methyl-L-lyxopyranose (1) with 3,4-di-O-benzyl-2,6-di-O-methyl-α-D-mannopyranosyl chloride afforded a mixture of the α,α- 12) and α,β-disaccharide derivative (10).Reaction of 1 with 3,4-di-O-benzyl-2,6-di-O-methyl-α-D-
- Olah, V. Anna,Harangi, Janos,Liptak, Andras
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p. 113 - 120
(2007/10/02)
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- Ditritylation of Methyl and Benzyl α-D-Gluco-, -Manno-, and -Galactopyranosides and Preparation of Their Partially Benzylated Derivatives
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The ditritylation of methyl and benzyl α-D-gluco-, -manno-, and -galactopyranosides with trityl chloride in pyridine at 70 deg C proceeds in a regioselective manner to give the 2,6-ditrityl ethers of the glucosides, the 3,6-ones of the mannosides, and bot
- Koto, Shinkiti,Morishima, Naohiko,Yoshida, Toyosaku,Uchino, Masaharu,Zen, Shonosuke
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p. 1171 - 1175
(2007/10/02)
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- CHEMO-, STEREO- AND REGIOSELECTIVE HYDROGENOLYSIS OF CARBOHYDRATE BENZYLIDENE ACETALS. SYNTHESIS OF BENZYL ETHERS OF BENZYL α-D-, METHYL β-D-MANNOPYRANOSIDES AND BENZYL α-D-RHAMNOPYRANOSIDE BY RING CLEAVAGE OF BENZYLIDENE DERIVATIVES WITH THE LiAlH4-AlCl3
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Treatment of benzyl α-(1) and methyl β-D-mannopyranoside (2) with α,α-dimethoxytoluene gave the exo and endo isomers (3,5 and 4,6) of the dibenzylidene derivatives of 1 and 2.Hydrogenolysis of the exo isomers (3 and 5) with a molar equivalent of AlH2Cl ga
- Liptak, Andras,Imre, Janos,Harangi, Janos,Nanasi, Pal,Neszmelyi, Andras
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p. 3721 - 3728
(2007/10/02)
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- SYNTHESIS OF A MODEL OF AN IMMER CHAIN OF CELL-WALL PROTEOHETEROGLYCAN ISOLATED FROM Piricularia oryzae: BRANCHED D-MANNOPENTAOSIDES
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Efficient syntheses are described of the branched D-mannopentaosides methyl 2,6-di-O-(2-O-α-D-mannopyranosyl-α-D-mannopyranosyl)-α-D-mannopyranoside and methyl 2,4-di-O-(2-O-α-D-mannopyranosyl-α-D-mannopyranosyl)-α-D-mannopyranoside, starting from the gly
- Ogawa, Tomoya,Sasajima, Kikuo
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