- Copper-Catalyzed Anomeric O-Arylation of Carbohydrate Derivatives at Room Temperature
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Direct and practical anomeric O-arylation of sugar lactols with substituted arylboronic acids has been established. Using copper catalysis at room temperature under an air atmosphere, the protocol proved to be general, and a variety of aryl O-glycosides have been prepared in good to excellent yields. Furthermore, this approach was extended successfully to unprotected carbohydrates, including α-mannose, and it was demonstrated here how the interaction between carbohydrates and boronic acids can be combined with copper catalysis to achieve selective anomeric O-arylation.
- Verdelet, Tristan,Benmahdjoub, Sara,Benmerad, Belkacem,Alami, Mouad,Messaoudi, Samir
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supporting information
p. 9226 - 9238
(2019/08/12)
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- Copper-mediated anomeric: O -arylation with organoboron reagents
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Copper-mediated couplings of arylboroxines with glycosyl hemiacetals furnish O-aryl glycosides via Csp2-O bond formation. The method enables the anomeric O-arylation of protected pyranose and furanose derivatives, and is tolerant of functionalized arylboroxine partners. Whereas mixtures of anomers are formed from glucopyranose, galactopyranose and arabinofuranose hemiacetals, the α-anomer is generated selectively from mannopyranose and mannofuranose-derived substrates.
- Dimakos, Victoria,Liu, Jacklyn J. W.,Ge, Zhenlu,Taylor, Mark S.
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supporting information
p. 5671 - 5674
(2019/06/18)
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- 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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- Revisit of the phenol O-glycosylation with glycosyl imidates, BF 3·OEt2 is a better catalyst than TMSOTf
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With BF3·OEt2 as the catalyst, the glycosylation of phenols with glycosyl trichloroacetimidates (or N-phenyl trifluoroacetimidates) bearing 2-O-participating groups leads to the desired 1,2-trans-O-glycosides in generally excellent yields without formation of the 1,2-cis-anomers. However, with TMSOTf as the catalyst, the outcomes of the corresponding phenol O-glycosylation are highly dependent on the nucleophilicity of the phenols; less nucleophilic is the phenol, higher amounts of the 1,2-cis-O-glycoside together with more side-products are generated. 1,2-Orthoesters have been found to be the major products at a low temperature (a higher temperature. BF 3·OEt2 is an effective catalyst to promote the conversion of 1,2-orthoesters into the corresponding 1,2-trans-O-glycosides. However, the 1,2-orthoesters could be converted into the dioxolenium triflate and glycosyl triflate in the presence of TMSOTf, these intermediates which might be in equilibrium with the glycosyl oxocarbenium related species lead to the final mixture of the α/β-O-glycosides and side-products.
- Li, Yali,Mo, Huaping,Lian, Gaoyan,Yu, Biao
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- Palladium-catalyzed ullmann-type reductive homocoupling of iodoaryl glycosides
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A catalytic synthesis of novel biaryl-linked divalent glycosides was achieved using an electroreductive palladium-catalyzed iodoaryl-iodoaryl coupling reaction. This new method was optimized for the synthesis of divalent biaryl-linked mannopyranosides that was subsequently generalized toward several carbohydrate substrates with yields up to 96%.
- Bergeron-Brlek, Milan,Giguere, Denis,Shiao, Tze Chieh,Saucier, Catherine,Roy, Rene
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scheme or table
p. 2971 - 2977
(2012/05/04)
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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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- Stereoselectivity of reactions at the glycoside center of carbohydrates: VII. Synthesis of aryl α- and -β-D-glucopyranosides by Helferich, catalyzed by boron trifluoride etherate
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13C NMR spectroscopy was used to study the stereoselectivity of glycosylation of phenols with the α and β anomers of penta-O-acetyl-D-glucopyranose, penta-O-trifluoroacetyl-D-glucopyranose, and 2,3,4,6-tetra-O-acetyl-1-O-trifluoroacetyl-D-glucopyranose in the presence of boron trifluoride etherate at varied temperature, time, and catalyst amount. The boron trifluoride etherate-catalyzed reaction of penta-O-acetyl-β -D-glucopyranose and 2,3,4,6-tetra-O-acetyl-1-O-trifluoroacetyl-β -D-glucopyranose with phenols occurs with a high stereocontrol to give, depending on conditions, predominantly 1,2-cis- or 1,2-trans-aryl-glycosides. This reaction can be used for preparative synthesis of the α- and β-anomeric forms of glycosides of a wide range of phenols.
- Sokolov,Zakharov,Studentsov
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p. 806 - 811
(2007/10/03)
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- The catalytic synthesis of aryl O-glycosides using triaryloxyboranes
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Triaryloxyboranes worked as highly reactive glycosyl acceptors of glycosyl acetates to afford aryl O-glycosides in excellent yields. A catalytic amount of ytterbium(III) trifluoromethanesulfonate activated the formation reaction of aryl O-glycosidic linka
- Yamanoi, Takashi,Yamazaki, Ippo
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p. 4009 - 4011
(2007/10/03)
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- Glycosylation of Phenols: Preparation of 1,2-cis and 1,2-trans Glycosylated Tyrosine Derivatives to be used in Solid-phase Glycopeptide Synthesis
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The synthesis of four building blocks, Nα-Fmoc-Tyr(Ac4-β-D-Glc)-OPfp 6, Nα-Fmoc-Tyr(Bz4-α-D-Glc)-OPfp 16, Nα-Fmoc-Tyr4-α-D-Glc-(1->4)-Ac3-β-D-Glc>-OPfp 9 and Nα-Fmo
- Jensen, Knud J.,Meldal, Morten,Bock, Klaus
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p. 2119 - 2130
(2007/10/02)
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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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- Novel Synthesis of Aryl 2,3,4,6-Tetra-O-acetyl-D-glucopyranosides
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The glucosidation of phenols with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl fluoride in the presence of BF3*OEt2 to give, predominantly, α-anomers has been studied.In the presence of an amine base, 1,1,3,3-tetramethylguanidine, however, enhanced β-selectivity was achieved.The former reaction provides a novel and useful synthesis of aryl 2,3,4,6-tetra-O-acetyl-α-D-glucopyranoside whilst the latter is effective for the glycosidation of relatively hindered phenols.
- Yamaguchi, Masahiko,Horiguchi, Akira,Fukuda, Akira,Minami, Toru
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p. 1079 - 1082
(2007/10/02)
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- Glycosidation catalust and process for preparing glycoside derivatives
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Disclosed are a glycosidation catalyst comprising at least one of heteropoly acids represented by the formula wherein X is P, As, Si or Ge, M is at least one species selected from the group consisting of Mo, W and V, a is 3 4 or 6, b is an integer of
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- Phosphorus Oxychloride-catalysed Synthesis of Glucosides
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Anhydrous POCl3 has now been found to be a useful catalyst for the synthesis of both the β- and α-anomers of acetylated aryl, alkyl and arylalkyl D-glucosides.
- Bhat, V. S.,Sinha, Bharati,Bose, J. L.
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p. 514 - 516
(2007/10/02)
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- α-Glucosylation of Phenols with Tetra-O-benzyl-α-D-glucose
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An α-glucosylation of phenols with 2,3,4,6-tetra-O-benzyl-α-D-glucopyranose is described.This uses a mixture of p-nitobenzenesulfonyl chloride, silver trifluoromethanesulfonate and triethylamine in dichloromethane in a two-stage treatment.
- Koto, Shinkiti,Morishima, Naohiko,Araki, Mihoko,Tsuchiya, Takuji,Zen, Shonosuke
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p. 1895 - 1896
(2007/10/02)
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