- Anomeric alkylations and acylations of unprotected mono- and disaccharides mediated by pyridoneimine in aqueous solutions
-
A site-specific deprotonation followed by alkylations and acylations of sugar hemiacetals to the corresponding alkyl glycosides and acylated sugars in aqueous solutions is disclosed herein. Pyridoneimine as a new base is developed to mediate the deprotonation of readily available sugar hemiacetals and further reactions with alkylation and acylation agents.
- Dey, Kalyan,Jayaraman, Narayanaswamy
-
supporting information
p. 2224 - 2227
(2022/02/17)
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- Synthesis of the hyper-branched core tetrasaccharide motif of chloroviruses
-
Chemical synthesis of complex oligosaccharides, especially those possessing hyper-branched structures with one or multiple 1,2-cisglycosidic bonds, is a challenging task. Complementary reactivity of glycosyl donors and acceptors and proper tuning of the s
- Mishra, Bijoyananda,Manmode, Sujit,Walke, Gulab,Chakraborty, Saptashwa,Neralkar, Mahesh,Hotha, Srinivas
-
p. 1315 - 1328
(2021/02/26)
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- Synthesis, Conformational Analysis, and Complexation Study of an Iminosugar-Aza-Crown, a Sweet Chiral Cyclam Analog
-
A new family of chiral C2 symmetric tetraazamacrocycles, coined ISAC for IminoSugar Aza-Crown, incorporating two iminosugars adopting a 4C1 conformation is disclosed. Multinuclear NMR experiments on the corresponding Cdsu
- Ardá, Ana,Blériot, Yves,Bordes, Alexandra,Désiré, Jér?me,Franconetti, Antonio,Guillard, Jer?me,Jiménez-Barbero, Jesús,Ménand, Micka?l,Perrin, Flavie,Poveda, Ana,Sollogoub, Matthieu,Tripier, Rapha?l,Troadec, Thibault
-
supporting information
(2020/03/26)
-
- A Synthetic Carbohydrate-Protein Conjugate Vaccine Candidate against Klebsiella pneumoniae Serotype K2
-
Klebsiella pneumoniae causes pneumonia and liver abscesses in humans worldwide and contains virulence factor capsular polysaccharides and lipopolysaccharides linked to the cell wall. Although capsular polysaccharides are good antigens for vaccine producti
- Ravinder, Mettu,Liao, Kuo-Shiang,Cheng, Yang-Yu,Pawar, Sujeet,Lin, Tzu-Lung,Wang, Jin-Town,Wu, Chung-Yi
-
p. 15964 - 15997
(2020/11/13)
-
- Preparation method of fondaparinux sodium disaccharide intermediate
-
The invention discloses a preparation method of fondaparinux sodium disaccharide intermediate. 1-O-substituent sulfonyl-2,3-bis-O-benzyl-4,6-O-benzylidene-beta-D-glucopyranose directly reacts with 1,6-dehydrated-2-deoxy-2-azido-3-O-acetyl-beta-D-glucopyranose to prepare the fondaparinux sodium disaccharide intermediate as shown in a formula I; and meanwhile, the fondaparinux sodium intermediate asshown in the formula I can be used as a raw material to synthesize fondaparinux sodium intermediate as shown in a formula IV. The preparation method is simple and small in steps, the yield is high, the atomic utilization rate is high, the three wastes are small, and the preparation method is suitable for industrial large-scale production. Please see the description for the formula.
- -
-
Paragraph 0053; 0054; 0055
(2020/02/19)
-
- Acid-Assisted Direct Olefin Metathesis of Unprotected Carbohydrates in Water
-
The ability to use unprotected carbohydrates in olefin metathesis reactions in aqueous media is demonstrated. By using water-soluble, amine-functionalized Hoveyda–Grubbs catalysts under mildly acidic aqueous conditions, the self-metathesis of unprotected alkene-functionalized α-d-manno- and α-d-galactopyranosides could be achieved through minimization of nonproductive chelation and isomerization. Cross-metathesis with allyl alcohol could also be achieved with reasonable selectivity. The presence of small quantities (2.5 vol %) of acetic acid increased the formation of the self-metathesis product while significantly reducing the alkene isomerization process. The catalytic activity was furthermore retained in the presence of large amounts (0.01 mm) of protein, underlining the potential of this carbon–carbon bond-forming reaction under biological conditions. These results demonstrate the potential of directly using unprotected carbohydrate structures in olefin metathesis reactions under mild conditions compatible with biological systems, and thereby enabling their use in, for example, drug discovery and protein derivatization.
- Timmer, Brian J. J.,Ramstr?m, Olof
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p. 14408 - 14413
(2019/11/11)
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- Synthesis, kinetics and inhibition of Escherichia coli Heptosyltransferase I by monosaccharide analogues of Lipid A
-
Gram-negative bacteria comprise the majority of microbes that cause infections that are resistant to pre-existing antibiotics. The complex cell wall architecture contributes to their ability to form biofilms, which are often implicated in hospital-acquired infections. Biofilms promote antibiotic resistance by enabling the bacteria to survive hostile environments such as UV radiation, pH shifts, and antibiotics. The outer membrane of Gram-negative bacteria contains lipopolysaccharide (LPS), which plays a role in adhesion to surfaces and formation of biofilms. The main focus of this work was the synthesis of a library of glycolipids designed to be simplified analogues of the Lipid A, the membrane embedded portion component of LPS, to be tested as substrates or inhibitors of Heptosyltransferase I (HepI or WaaC, a glycosyltransferase enzyme involved in the biosynthesis of LPS). Fourteen analogues were synthesized successfully and characterized. While these compounds were designed to function as nucleophilic substrates of HepI, they all demonstrated mild inhibition of HepI. Kinetic characterization of inhibition mechanism identified that the compounds exhibited uncompetitive and mixed inhibition of HepI. Since both uncompetitive and mixed inhibition result in the formation of an Enzyme-Substrate-inhibitor complex, molecular docking studies (using AutoDock Vina) were performed, to identify potential allosteric binding site for these compounds. The inhibitors were shown to bind to a pocket formed after undergoing a conformational change from an open to a closed active site state. Inhibition of HepI via an allosteric site suggest that disruption of protein dynamics might be a viable mechanism for the inhibition of HepI and potentially other enzymes of the GT-B structural class.
- Nkosana, Noreen K.,Czyzyk, Daniel J.,Siegel, Zarek S.,Cote, Joy M.,Taylor, Erika A.
-
supporting information
p. 594 - 600
(2018/02/19)
-
- Glycosyl Aldehydes: New Scaffolds for the Synthesis of Neoglycoconjugates via Bioorthogonal Oxime Bond Formation
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The straightforward preparation of glycosyl neoconjugates by oxime (or hydrazone) bond formation represents a key bioorthogonal tool in chemical biology. However, when this strategy is employed by reacting the reducing end of the glycan moiety, the configuration and the stereochemical information is lost due to partial (or complete) opening of the glycan cyclic hemiacetal and the formation of the corresponding opened tautomers. We have completed the synthesis of a library of glycosyl aldehydes to be used as scaffold for the synthesis of neoglycoconjugates via oxime bond formation. These glycosyl aldehydes constitute a simple and accessible alternative to avoid loss of chiral information when conjugating, by oxime (or hydrazone) bonds, the aldehyde functionality present at the reducing end of natural carbohydrates.
- Reina, José J.,Rioboo, Alicia,Montenegro, Javier
-
p. 831 - 845
(2018/01/11)
-
- Chemical Synthesis of Modified Hyaluronic Acid Disaccharides
-
Herein we report a chemical synthesis towards new modified hyaluronic acid oligomers by using only commercially available d-glucose and d-glucosamine hydrochloride. The various protected hyaluronic acid disaccharides were synthesized bearing new functional groups at C-6 of the β-d-glucuronic acid moiety with a view to structure-related biological activity tests. The orthogonal protecting group pattern allows ready access to the corresponding higher oligomers. Also, 1H NMR studies of the new derivatives demonstrated the effect of the various functional groups on the intramolecular electronic environment.
- Mende, Marco,Nieger, Martin,Br?se, Stefan
-
supporting information
p. 12283 - 12296
(2017/09/14)
-
- β-1,6-GLUCAN CETUXIMAB ANTIBODY CONJUGATES
-
The present invention encompasses embodiments in which cetuximab or a related cetuximab antibody is conjugated to β-1,6-glucan oligomers. Thus, the present invention includes, among other things, compositions including cetuximab conjugated to one or more
- -
-
Paragraph 0248; 0253; 0254
(2016/12/22)
-
- Direct glycosylation of unprotected and unactivated sugars using bismuth nitrate pentahydrate
-
Bi(NO3)3, a low-cost, mild, and environmentally green catalyst, has been successfully utilized for Fischer glycosylation for the synthesis of alkyl/aryl glycopyranosides by reacting unprotected sugars, namely, D-glucose, L-rhamnose, D-galactose, D-arabinose, and N-acetyl-D-glucosamine with various alcohols in good to excellent yields. The glycosides were formed with high α-selectivity. Further, an expedient separation of α- and β-glycosides using silver nitrate-impregnated silica gel flash liquid chromatography has been developed.
- Polanki, Innaiah K.,Kurma, Siva H.,Bhattacharya, Asish K.
-
p. 196 - 205
(2015/06/08)
-
- Carbohydrate-derived iminium salt organocatalysts for the asymmetric epoxidation of alkenes
-
A new family of carbohydrate-based dihydroisoquinolinium salts has been prepared and tested for potential as asymmetric catalysts for the epoxidation of unfunctionalized alkene substrates, providing up to 57% ee in the product epoxides.
- Bulman Page, Philip C.,Chan, Yohan,Liddle, John,Elsegood, Mark R.J.
-
p. 7283 - 7305
(2017/09/13)
-
- 1,2-cis Alkyl glycosides: Straightforward glycosylation from unprotected 1-thioglycosyl donors
-
A 1,2-cis-alkyl glycosidation protocol that makes use of unprotected phenyl 1-thioglycosyl donors is reported. Glycosylation of various functionalized alcohols was accomplished in moderate to high yield and selectivity to give the 1,2-cis-glycosides. In order to quickly develop optimum glycosylation conditions, an FIA (flow injection analysis)-ESI-TOF-MS method was developed that enabled rapid and quantitative evaluation of yield on small scale. This methodology, coupled with NMR spectroscopy, allowed for rapid evaluation of the overall reactions.
- Meng, Bo,Zhu, Zhenqian,Baker, David C.
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p. 5182 - 5191
(2014/07/08)
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- Regiospecific anomerisation of acylated glycosyl azides and benzoylated disaccharides by using TiCl4
-
Chelation induced anomerisation is promoted when Lewis acids, such as TiCl4 or SnCl4, coordinate to the pyranose ring oxygen atom and another site, giving rise to endocyclic cleavage and isomerisation to the more stable anomer. In this research regiospecific site-directed anomerisation is demonstrated. TiCl4 (2.5equiv) was employed to induce anomerisation of 15 glycosyl azide and disaccharide substrates of low reactivity, and high yields (>75 %) and stereoselectivies (α/β>9:1) were achieved. The examples included glucopyranuronate, galactopyranuronate and mannopyranuronate as well as N-acetylated glucopyranuronate and galactopyranuronate derivatives. A disaccharide with the α1→4 linkage found in polygalacturonan was included. The use of benzoylated saccharides was found to be important in disaccharide anomerisation as attempts to isomerise related acetyl protected and 2,3-carbonate protected derivatives were not successful. Copyright
- Farrell, Mark,Zhou, Jian,Murphy, Paul V.
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p. 14836 - 14851
(2013/11/06)
-
- Synthesis of oligosaccharide fragments of the rhamnogalacturonan of Nerium indicum
-
Three trisaccharides, one pentasaccharide, and one heptasaccharide, namely α-D-GalA-(1→2)-α-L-Rha-(1→4)-β-D-GalA-OC 3H7 (1), α-L-Rha-(1→4)-α-D-GalA- (1→4)-β-D-GalA-OC3H7 (2), α-D-GalA- (1→4)-α-DGalA-(1→2)-α-L-Rh
- Ma, Yuyong,Cao, Xin,Yu, Biao
-
-
- An unusual synthesis of 2-pyridone and 3,5-dihydroxypyridine from a carbohydrate
-
An unusual aromatization to perbenzylated 3,5-dihydroxy-6-(hydroxymethyl)- 2-pyridone was demonstrated utilizing sugar lactam, under strong basic conditions, derived from d-Galactose. 2-Pyridone was efficiently converted into a pharmaceutically relevant s
- Gorantla, Jaggaiah N.,Kovval, Divya,Lankalapalli, Ravi S.
-
supporting information
p. 3230 - 3232
(2013/06/27)
-
- Structural Studies of the O-Acetyl-Containing O-Antigen from a Shigella flexneri Serotype 6 Strain and Synthesis of Oligosaccharide Fragments Thereof
-
Extensive analysis by NMR spectroscopy of the delipidated lipopolysaccharide of Shigella flexneri serotype 6 strain MDC 2924-71 confirmed the most recently reported structure of the O-antigen repeating unit as {→4)-β-D-GalpA-(1→3)-β-D-GalpNAc-(1→2) -α-L-R
- Chassagne, Pierre,Fontana, Carolina,Guerreiro, Catherine,Gauthier, Charles,Phalipon, Armelle,Widmalm, Goeran,Mulard, Laurence A.
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p. 4085 - 4106
(2013/07/26)
-
- OLEFIN METATHESIS REACTIONS OF AMINO ACIDS, PEPTIDES AND PROTEINS CONTAINING ALLYL SULFIDE GROUPS
-
A method for the modification of an amino acid, protein or peptide is disclosed. The method comprises reacting a carbon-carbon double bond-containing compound with an amino acid, a protein or a peptide containing an allyl sulfide group in the presence of a catalyst which promotes olefin metathesis, to form a modified amino acid, protein or peptide. Preferred carbon-carbon double bond-containing compounds include carbohydrates.
- -
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Page/Page column 7
(2012/07/27)
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- Stereoselective dihydroxylation reaction of alkenyl β- D -hexopyranosides: A methodology for the synthesis of glycosylglycerol derivatives and 1-O-Acyl-3-O-β- D -glycosyl-sn-glycerol analogues
-
A variety of new glycosylglycerol derivatives have been prepared by stereoselective dihydroxylation of a range of alkenyl β-D-hexopyanosides under Donohoe's conditions. We have studied the relationship between the diastereoisomeric excess and the structural features of the precursor (sugar and alkenyl moieties). The stereochemical yields demonstrated that the presence of a hydrogen-bond donor group (OH, NHAc) at the 2-position of the sugar moiety is required to obtain high levels of stereofacial discrimination. New 1-O-acyl-3-O-β-D-glycosyl-sn-glycerol analogues were obtained by functionalisation of the primary hydroxy group with a fatty acid. Preliminary cytotoxic activity assays of both glycosylglycerol and glycoglycerolipid analogues are also presented. An efficient asymmetric dihydroxylation reaction of alkenyl β-D-hexopyranoside derivatives is described. New glycosylglycerol and glycoglycerolipid analogues have been synthesised by this methodology. Preliminary cytotoxic activity assays are presented. Copyright
- Vega-Perez, Jose M.,Palo-Nieto, Carlos,Perinan, Ignacio,Vega-Holm, Margarita,Calderon-Montano, Jose M.,Lopez-Lazaro, Miguel,Iglesias-Guerra, Fernando
-
experimental part
p. 1237 - 1252
(2012/04/10)
-
- Fluorine-directed β-galactosylation: Chemical glycosylation development by molecular editing
-
Validation of the 2-fluoro substituent as an inert steering group to control chemical glycosylation is presented. A molecular editing study has revealed that the exceptional levels of diastereocontrol in glycosylation processes by using 2-fluoro-3,4,6-tri-O-benzyl glucopyranosyl trichloroacetimidate (TCA) scaffolds are a consequence of the 2R,3S,4S stereotriad. This study has also revealed that epimerization at C4, results in a substantial enhancement in β-selectivity (up to β/α 300:1). Copyright
- Durantie, Estelle,Bucher, Christoph,Gilmour, Ryan
-
supporting information; experimental part
p. 8208 - 8215
(2012/08/27)
-
- Synthesis of trisaccharides by hetero-diels-alder welding of two monosaccharide units
-
A new strategy for the synthesis of di- and trisaccharides based on the de novo synthesis of the linking saccharide unit is presented. In this strategy, functionalized monosaccharide building blocks already incorporating the glycosidic linkages are welded together using a metal-catalyzed hetero-Diels-Alder (HDA) reaction to generate a new monosaccharide unit between them. The highest yields and selectivities in the HDA reaction were obtained by using chiral Schiff base chromium complexes. Disaccharide products were accessible by reaction of Danishefsky's diene with acetyl- and benzyl-protected galactoside aldehydes. For the synthesis of trisaccharide products, acetyl-protected glucose or galactose-derived dienes were fused with monosaccharide-derived aldehydes using chromium catalysts for the HDA reaction. The desired trisaccharide products were obtained in moderate to good yields with excellent stereoselectivity. The central pyranulose-ring generated in the process possessed an L-cis-enulose configuration according to NMR spectroscopy and modeling studies. 1 + 1 equals 3! The hetero-Diels-Alder union of two functionalized monosaccharide building blocks - one bearing an aldehyde and the other a readily accessible diene moiety - affords functionalized trisaccharide structures in moderate to good yields and excellent stereoselectivities when β-anomers of the aldehydes are used. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
- Himanen, Jatta A.,Pihko, Petri M.
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p. 3765 - 3780
(2012/09/25)
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- Structurally diverse disaccharide analogs of antifreeze glycoproteins and their ability to inhibit ice recrystallization
-
The β-D-galactosyl-(1,3)-α-N-acetyl-D-galactosamine disaccharide is present in antifreeze glycoproteins (AFGPs). Analogs of this disaccharide including the β-linked (1,3)-, (1,4)-, and (1,6)-galactosyl-N-acetyl galactosamine and the β-(1,3)-galactosyl-galactoside were synthesized and evaluated for ice recrystallization inhibition (IRI) activity. The results from this study demonstrate that the b-linked-(1,4) disaccharide exhibits more potent IRI activity than the native b-linked-(1,3) disaccharide. The C2 N-acetyl group of the disaccharide does not affect IRI activity but in monosaccharides, the presence of the C2 N-acetyl group decreases IRI activity. The current study will facilitate the design of potent small-molecule ice recrystallization inhibitors.
- Balcerzak, Anna K.,Ferreira, Sandra S.,Trant, John F.,Ben, Robert N.
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p. 1719 - 1721
(2012/04/04)
-
- Synthesis of a glycodendrimer incorporating multiple mannosides on a glucoside core
-
The synthesis of a glycodendrimer by incorporating repetitive mannoside units onto a glucoside core was carried out to multivalently probe fundamental carbohydrate-protein interactions. The dendritic structure was constructed by a modified procedure that
- Wang, Chao,Sanders, Brian,Baker, David C.
-
experimental part
p. 959 - 963
(2011/10/10)
-
- COMPOUND RETAINED IN TUMOR
-
A novel compound which specifically resides in a tumor, a method for allowing it to reside in a tumor, and a method for detecting, diagnosing, and treating tumor with use thereof are provided. The present invention relates to a compound represented by chemical formula (I) wherein R is an anionic group binding to hydrogen, R1 is OH, OCOH, OCO(CH2)hCH3, or an acting group, h being an integer of 0 or more, R2 is H, OH, OCOH, OCO(CH2)iCH3, or an acting group, i being an integer of 0 or more, R3 is OH, SO3H, or an acting group, R4 is OH, SO3H, or an acting group, and R5 is OH, SO3H, or an acting group, at least one of R1, R2, R3, R4, and R5 containing an acting group, or pharmaceutically acceptable salts thereof.
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Page/Page column 48
(2011/12/03)
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- Green glycosylation promoted by reusable biomass carbonaceous solid acid: An easy access to β-stereoselective terpene galactosides
-
An efficient green protocol has been developed for the atom economic glycosylation of unprotected, unactivated glycosyl donors and glycosylation of glycosyl trichloroacetimidates with the aid of reusable eco-friendly biomass carbonaceous solid acid as catalyst. The Royal Society of Chemistry.
- Gorityala, Bala Kishan,Ma, Jimei,Pasunooti, Kalyan Kumar,Cai, Shuting,Liu, Xue-Wei
-
supporting information; experimental part
p. 573 - 577
(2011/05/06)
-
- Kinetic products under thermal conditions: Rapid entry into α/β-D-galactofuranosides using microwave irradiation and selective Lewis acids
-
A modified Fischer-Lubineau reaction, employing microwave irradiation and selected Lewis acids such as Mn(ClO4)2, Mn(C 2H3O2)3, FeCl3, CoCl 2, and AgF as independent a
- Santra, Soumava,Jonas, Emily,Bourgault, Jean-Paul,El-Baba, Tarick,Andreana, Peter R.
-
experimental part
p. 27 - 40
(2012/01/17)
-
- Olefin cross-metathesis on proteins: Investigation of allylic chalcogen effects and guiding principles in metathesis partner selection
-
Olefin metathesis has recently emerged as a viable reaction for chemical protein modification. The scope and limitations of olefin metathesis in bioconjugation, however, remain unclear. Herein we report an assessment of various factors that contribute to productive cross-metathesis on protein substrates. Sterics, substrate scope, and linker selection are all considered. It was discovered during this investigation that allyl chalcogenides generally enhance the rate of alkene metathesis reactions. Allyl selenides were found to be exceptionally reactive olefin metathesis substrates, enabling a broad range of protein modifications not previously possible. The principles considered in this report are important not only for expanding the repertoire of bioconjugation but also for the application of olefin metathesis in general synthetic endeavors.
- Lin, Yuya A.,Chalker, Justin M.,Davis, Benjamin G.
-
supporting information; experimental part
p. 16805 - 16811
(2011/02/17)
-
- Synthesis of benzaldehyde-functionalized glycans: A novel approach towards glyco-SAMs as a tool for surface plasmon resonance studies
-
In recent years the interest in tools for investigating carbohydrateprotein (CPI) and carbohydrate-carbohydrate interactions (CCI) has increased significantly. For the investigation of CPI and CCI, several techniques employing different linking methods are available. Surface plasmon resonance (SPR) imaging is a most appropriate tool for analyzing the formation of self-assembled monolayers (SAM) of carbohydrate derivatives, which can mimic the glycocalyx. In contrast to the SPR imaging methods used previously to analyze CPI and CCI, the novel approach reported herein allows a facile and rapid synthesis of linker spacers and carbohydrate derivatives and enhances the binding event by controlling the amount and orientation of ligand. For immobilization on biorepulsive amino-functionalized SPR chips by reductive amination, diverse aldehyde-functionalized glycan structures (glucose, galactose, mannose, glucosamine, cellobiose, lactose, and lactosamine) have been synthesized in several facile steps that include olefin metathesis. Effective immobilization and the first binding studies are presented for the lectin concanavalin A.
- Kopitzki, Sebastian,Jensen, Knud J.,Thiem, Joachim
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supporting information; experimental part
p. 7017 - 7029
(2010/09/10)
-
- Alkenyl β-d-galactopyranoside derivatives as efficient chiral templates in stereoselective cyclopropanation and epoxidation reactions
-
The synthesis of a wide range of alkenyl 4,6-O-(S)-benzylidene-β-d-galactopyranosides is described. The cyclopropanation and epoxidation reactions of these compounds were developed. Cyclopropanation reactions took place with high stereoselectivity giving diastereomeric excesses of up to 100%. As a part of our aim in studying hydroxyl-directed reactions, their epoxidation with m-CPBA was carried out. High diastereomeric excesses (80-100%) were obtained when the hydroxyl group at C-2 of the auxiliary was unprotected. The β-d-galactopyranoside moiety constitutes as an interesting auxiliary, due to its efficient chirality transfer capability as well as providing a way to obtain a variety of glycolipid derivatives.
- Vega-Perez, Jose M.,Perinan, Ignacio,Palo-Nieto, Carlos,Vega-Holm, Margarita,Iglesias-Guerra, Fernando
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experimental part
p. 81 - 95
(2010/04/06)
-
- Total synthesis of 3,3-difluorinated 1-deoxynojirimycin analogues
-
Difluorination of 1-deoxynojirimycin at position C(3) creates a competitive inhibitor 15 of 10 times higher activity against an α-glucosidase than the parent compound. Its screening against a panel of human cell lines showed a low cytotoxicity therefore m
- Csuk, René,Prell, Erik,Korb, Claudia,Kluge, Ralph,Str?hl, Dieter
-
scheme or table
p. 467 - 472
(2010/04/04)
-
- Exploiting the cross-metathesis reaction in the synthesis of pseudo-oligosaccharides
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An approach to the synthesis of pseudo-oligosaccharides based on the cross-metathesis reaction between distinct sugar-olefins, followed by intramolecular cyclization of the obtained heterodimer, is presented. In particular, the relative efficiency of two
- Ronchi, Paolo,Vignando, Stefano,Guglieri, Sara,Polito, Laura,Lay, Luigi
-
body text
p. 2635 - 2644
(2009/10/30)
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- Green glycosylation using ionic liquid to prepare alkyl glycosides for studying carbohydrate-protein interactions by SPR
-
Several simple glycosides of d-glucose (Glc) and N-acetyl-d-galactosamine (GalNAc) were prepared in a single step glycosylation reaction using unprotected and unactivated sugar donors. The resulting GalNAc glycoside, containing a bifunctional linker, was used to immobilize this glycoconjugate to a self assembled monolayer on a gold biosensor chip. Surface plasmon resonance (SPR) experiments demonstrated that this immobilized glycoconjugate bound to GalNAc specific lectin, Viscum album agglutinin.
- Javier Munoz,Andre, Sabine,Gabius, Hans-Joachin,Sinisterra, Jose V.,Hernaiz, Maria J.,Linhardt, Robert J.
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experimental part
p. 373 - 379
(2010/04/22)
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- Ionic liquid promoted atom economic glycosylation under Lewis acid catalysis
-
Straightforward glycosylation of various alcohols with unprotected and non-activated monosaccharides were performed under scandium triflate catalysis. Rate and yield of glycosylation were highly improved when using 1-butyl-3-methylimidazolium trifluoromethanesulfonate as a green solvent. This ionic liquid was allowed to be recycled at least three times without loss of activity. The possibility of drastically reducing the amounts of catalyst (down to 1 mol%) and aglycone (down to 1 equiv) when performing the reaction in ionic liquid opens new perspectives in O-glycosylation, as a direct coupling between an aglycone and free sugars.
- Auge, Jacques,Sizun, Gwenaelle
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scheme or table
p. 1179 - 1183
(2010/05/02)
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- Glycosylation using unprotected alkynyl donors
-
(Chemical Equation Presented) Gold(III) activation of unprotected propargyl glycosyl donors has been shown to be effective for the synthesis of saccharides. Terminal propargyl glycosides of glucose, galactose, and mannose required heating at reflux in ace
- Mamidyala, Sreeman K.,Finn
-
experimental part
p. 8417 - 8420
(2010/01/16)
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- Allyl sulfides are privileged substrates in aqueous cross-metathesis: Application to site-selective protein modification
-
Allyl sulfides undergo efficient cross-metathesis in aqueous media with Hoveyda-Grubbs second generation catalyst 1. The high reactivity of allyl sulfides in cross-metathesis was exploited in the first examples of cross-metathesis on a protein surface. S-Allylcysteine was incorporated chemically into the protein, providing the requisite allyl sulfide handle. Preliminary efforts to genetically incorporate S-allylcysteine into proteins are also reported. Copyright
- Lin, Yuya A.,Chalker, Justin M.,Floyd, Nicola,Bernardes, Goncalo J. L.,Davis, Benjamin G.
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supporting information; experimental part
p. 9642 - 9643
(2009/02/04)
-
- Montmorillonite K-10 as a reusable catalyst for fischer type of glycosylation under microwave irradiation
-
Montmorillonite K-10-catalyzed Fischer type glycosylation was studied for various monosacharides with different alcohols under microwave irradiation. The method was found to be efficient, economic, simple, and time saving and the catalyst montmorillonite K-10 was reused three times without loss of catalytic activity and anomeric selectivity. With glycerol, the method gave products glycosylated at primary alcohols only.
- Bordoloi, Manobjyoti
-
p. 300 - 308
(2008/12/21)
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- The stereochemical dependence of unimolecular dissociation of monosaccharide-glycolaldehyde anions in the gas phase: A basis for assignment of the stereochemistry and anomeric configuration of monosaccharides in oligosaccharides by mass spectrometry via a key discriminatory product ion of disaccharide fragmentation, m/z 221
-
Mass spectrometry of hexose-containing disaccharides often yields product ions of m/z 221 in the negative ion mode. Using a Paul trap, isolation and collision-induced dissociation of the m/z 221 anions yielded mass spectra that easily differentiated their stereochemistry and anomeric configuration, for all 16 stereochemical variants. The ions were shown to be glycopyranosyl- glycolaldehydes through chemical synthesis of their standards. The stereochemistry dramatically affected fragmentation which was dependent on four relative stereochemical arrangements: (1) the relationship between the hydroxyl group at position 2 and the anomeric configuration, (2) a cis relationship of the anomeric position and positions 2 and 3 (1,2,3-cis), (3) a 1,2 trans-2,3 cis relationship, and (4) the relationship between the hydroxyl group at position 4 and the anomeric configuration. After labeling the reducing carbonyl oxygen of a series of disaccharides with 18O to mass-discriminate between their monosaccharide components, it was demonstrated that m/z 221 anions are comprised of an intact nonreducing sugar glycosidically linked to a 2-carbon aglycon derived from the reducing sugar, irrespective of the linkage position between monosaccharides. This enabled the location of the intact sugar to be assigned to the nonreducing side of a glycosidic linkage. Detailed studies of experimental factors necessary for reproducibility demonstrated that the unique mass spectrum for each m/z 221 anion could be obtained from month-to-month through the use of an internal energy-input calibrant ion that ensured reproducible energy deposition into the ions. The counterparts to these ions for the 2-acetamido-2-deoxyhexoses were m/z 262 anions, and the anomeric configuration and stereochemistry of these anions could also be reproducibly discriminated for N-acetylglucosamine and N-acetylgalactosamine. The fragmentation patterns of m/z 221 anions provide a firm reproducible basis for assignment of sugar stereochemistries in the gas phase.
- Fang, Tammy T.,Bendiak, Brad
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p. 9721 - 9736
(2008/03/13)
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- Synthetic routes to three novel scaffolds for potential glycosidase inhibitors
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Efficient syntheses of three novel scaffolds for potential β-glycosidase inhibitors were developed: The first consists of a 2,7-dioxabicyclo[2.2.1]heptane derivative, which was prepared by an intramolecular ketalisation. The second scaffold consists of a
- Rommel, Michael,Ernst, Alexander,Koert, Ulrich
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p. 4408 - 4430
(2008/09/17)
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- Differentiation of the anomeric configuration and ring form of glucosyl-glycolaldehyde anions in the gas phase by mass spectrometry: isomeric discrimination between m/z 221 anions derived from disaccharides and chemical synthesis of m/z 221 standards
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Mass spectrometry of disaccharides in the negative-ion mode frequently generates product anions of m/z 221. With glucose-containing disaccharides, dissociation of isolated m/z 221 product ions in a Paul trap yielded mass spectra that easily differentiated between both anomeric configurations and ring forms of the ions. These ions were shown to be glucosyl-glycolaldehydes through chemical synthesis of their standards. By labeling the reducing carbonyl oxygen of disaccharides with 18O to mass discriminate between monosaccharides, it was established that the m/z 221 ions are comprised solely of an intact nonreducing sugar with a two-carbon aglycon derived from the reducing sugar, regardless of the disaccharide linkage position. This enabled the anomeric configuration and ring form of the ion to be assigned and the location of the ion to the nonreducing side of a glycosidic linkage to be ascertained. Detailed studies of experimental factors necessary for reproducibility in a Paul trap demonstrated that the unique dissociation patterns that discriminate between the isomeric m/z 221 ions could be obtained from month-to-month in conjunction with an internal energy-input calibrant ion that ensures reproducible energy deposition into isolated m/z 221 ions. In addition, MS/MS fragmentation patterns of disaccharide m/z 341 anions in a Paul trap enabled linkage positions to be assigned, as has been previously reported with other types of mass spectrometers.
- Fang, Tammy T.,Zirrolli, Joseph,Bendiak, Brad
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p. 217 - 235
(2007/10/03)
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- Synthesis of neosaponins and neoglycolipids containing a chacotriosyl moiety
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α-l-Rhamnopyranosyl-(1→4)-[α-l-rhamnopyranosyl-(1→2)]-β-d-glucopyranose (chacotriose) is the oligosaccharide moiety of dioscin. Chacotriosyl trichloroacetimidate was synthesized from d-glucose and l-rhamnose, and glycosylated to mevalonate (diosgenin, cholesterol, and glycyrrhetic acid) to yield dioscin and neosaponins. In order to simplify the structure of the aglycone part, the mevalonate moiety was replaced with double-chain neoglycolipids that mimicked glycosyl ceramides. A cytotoxicity test revealed the importance of the glycosidic linkage of the naturally occurring β-form and that dioscin and the neoglycolipid with the longest chain showed a moderate activity.
- Miyashita, Hiroyuki,Ikeda, Tsuyoshi,Nohara, Toshihiro
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p. 2182 - 2191
(2008/02/12)
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- Orthogonally protected cyclo-β-tetrapeptides as solid-supported scaffolds for the synthesis of glycoclusters
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Two novel peptide scaffolds, viz. cyclo[(Nα-Alloc)Dpr- β-Ala-(Nα-Fmoc)Dpr-β-Ala] (1) and cyclo[(N α-Alloc)Dpr-α-azido-β-aminopropanoyl-(N α-Fmoc)Dpr-/β-Ala] (2), composed of orthogonally protected 2,3-diaminopro
- Virta, Pasi,Karskela, Marika,Loennberg, Harri
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p. 1989 - 1999
(2007/10/03)
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- Synthesis of 1-deoxyhept-2-ulosyl-glycono-1,5-lactone utilizing α-selective O-glycosidation of 2,6-anhydro-1-deoxy-d-hept-1-enitols
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A series of 1-deoxy-heptulo-2-pyranosyl-glycono-1,5-lactones were synthesized utilizing completely α-selective O-glycosidation of heptenitols. Anomeric configuration of the products was confirmed by 3JC,H coupling measurement and X-ray crystal structural analysis. The benzyl-protected ketosyl saccharides were partly unstable, and glycosidic linkage was prone to cleave under the usual debenzylation conditions. To prevent this, we surveyed various additives for the Pd-catalyzed hydrogenation reaction and found that basic alumina was the most effective.
- Namme, Rie,Mitsugi, Takashi,Takahashi, Hideyo,Shiro, Moto,Ikegami, Shiro
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p. 9183 - 9192
(2007/10/03)
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- Synthesis of novel bicyclic ketals of galacturonic acid as potential glycosidase inhibitors
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A synthesis of novel bicyclic ketals of galacturonic acid is described. The key cyclisation step was realised under acidic anhydrous conditions in very good yield. X-ray crystal structure analysis determined the correct regio- and stereochemistry. Georg T
- Rommel, Michael,Ernst, Alexander,Harms, Klaus,Koert, Ulrich
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p. 1067 - 1070
(2007/10/03)
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- A short route for the synthesis of "sweet" macrocycles via a click-dimerization-ring-closing metathesis approach
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A facile and flexible approach for the preparation of macrocyclic molecules containing different carbohydrate moieties is presented, employing the reaction cascade: click-dimerization and ring-closing metathesis. The Royal Society of Chemistry 2005.
- Doerner, Simon,Westermann, Bernhard
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p. 2852 - 2854
(2007/10/03)
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- Microwave-accelerated Fischer glycosylation
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Fischer glycosylation has been used for decades for the synthesis of simple alkyl and aryl glycosides from free sugars. The reaction proceeds under reflux in the presence of catalytic acid with the alcohol as solvent. The main deficiency of this reaction is the long reaction time required. In this study microwave heating has been utilised for the Fischer glycosylation reaction of N-acetyl-d-glucosamine, N-acetyl-d-galactosamine, d-glucose, d-galactose and d-mannose with a variety of alcohols (methanol, ethanol, benzyl alcohol and allyl alcohol). Remarkable acceleration of the glycosylation reactions (minutes compared to hours) over conventional reflux heating was observed with good yields and production of the α-glycoside as the dominant product.
- Bornaghi, Laurent F.,Poulsen, Sally-Ann
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p. 3485 - 3488
(2007/10/03)
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- Simple preparation of phenylpropenoid β-D-glucopyranoside congeners by Mizoroki-Heck type reaction using organoboron reagents
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Palladium(II)-catalyzed carbon-carbon bond formation between allyl 2,3,4,6-tetra-O-acetyl-β-d-glucopyranoside (3) and arylboronic acid congeners gave the corresponding cinnamyl 2,3,4,6-tetra-O-acetyl- β-d-glucopyranosides (4a-m) in good yield. Among them, coupling products 4a-m were converted to not only the naturally occurring phenylpropenoid β-d-glucopyranoside analogues (1a-e) but also the unnaturally ones (1f-m).
- Kishida, Masashi,Akita, Hiroyuki
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p. 10559 - 10568
(2007/10/03)
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- Synthesis of ω-unsaturated O-protected glucosides as precursors for unsaturated neutral bolaforms
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The Lewis acid catalyzed glycosylation reaction of βperacetylated sugar derivative (glucose) with terminally unsaturated C3-C11-alkenols is used in a synthesis of some C3-C11alkenyl glucopyranosides as precursors for unsaturated neutral bolaforms. The process occurs under the influence of tin(IV) chloride.
- Konstantinovi?,Predojevi?,Gojkovi?,Pavlovi?
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p. 666 - 669
(2007/10/03)
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- Incorporating α-allyl glucoside into polyacrylonitrile by water-phase precipitation copolymerization to reduce protein adsorption and cell adhesion
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α-Allyl glucoside (AG) was incorporated into polyacrylonitrile by water-phase precipitation copolymerization (WPPCP) for the first time with K2S2O8-Na2SO3 as initiator system to improve the resistance
- Xu, Zhi-Kang,Kou, Rui-Qiang,Liu, Zhen-Mei,Nie, Fu-Qiang,Xu, You-Yi
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p. 2441 - 2447
(2007/10/03)
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- Synthesis of neosaponins having an α-L-rhamnopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]- D-glucopyranosyl glyco-linkage
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To verify the role of the α-L-rhamnopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]- β-D-glucopyranosyl (chacotriosyl) moiety of steroidal glycosides from Solaum plants in their antitumor and antivirus activities, chacotriosides of diosgenin, cholesterol, and glycrrhetic acid were synthesized by developing our trans-oligoglycosidation. The chacotriosyl trichloroacetimidate was linked to the aglycones to afford neoglycosides as a mixture of α and β anomers, that was easily separated with ODS chromatography.
- Ikeda, Tsuyoshi,Miyashita, Hiroyuki,Kajimoto, Tetsuya,Nohara, Toshihiro
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p. 2353 - 2356
(2007/10/03)
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- A practical synthetic method for α- and β-glycosyloxyacetic acids
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Dihydroxylation of allyl 2,3,4-tri-O-benzyl-6-O-tritylglycosides provides diols, the anomers of which can easily be separated by column chromatography in a practical scale. These anomers can be cleanly transformed into α- and β-glycosyloxyacetic acids, respectively, via oxidative cleavage of the diol followed by oxidation.
- Mandai, Tadakatsu,Okumoto, Hiroshi,Oshitari, Tetsuta,Nakanishi, Katsuyoshi,Mikuni, Katsuhiko,Hara, Ko-Ji,Hara, Ko-Zo
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p. 129 - 132
(2007/10/03)
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