- A versatile approach to the synthesis of glycans containing mannuronic acid residues
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Reported herein is a new method for a highly effective synthesis of β-glycosides from mannuronic acid donors equipped with the 3-O-picoloyl group. The stereocontrol of glycosylations was achieved by means of the H-bond-mediated aglycone delivery (HAD). The method was utilized for the synthesis of a tetrasaccharide linkedviaβ-(1 → 3)-mannuronic linkages. We have also investigated 3,6-lactonized glycosyl donors that provided moderate to high β-manno stereoselectivity in glycosylations. A method to achieve complete α-manno stereoselectivity with mannuronic acid donors equipped with 3-O-benzoyl group is also reported.
- Alex, Catherine,Visansirikul, Satsawat,Demchenko, Alexei V.
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p. 2731 - 2743
(2021/04/07)
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- Beta-D-glucose short-chain fatty acid ester compound as well as preparation method and application thereof
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The invention discloses a beta-D-glucose short-chain fatty acid ester compound as well as a preparation method and application thereof, and belongs to the technical field of organic synthesis. The compound is a compound shown as a formula I, or a stereoisomer, a pharmaceutically acceptable salt, a solvate or a prodrug of the compound shown as the formula I. The formula is as shown in the description, wherein R is a methyl group, an ethyl group, a propyl group, a propylene group, an isopropylidene group, a butyl group, a butylidene group, an isobutylidene group, an amyl group, a pentylidene group or an isoamylidene group. The compound has potential prevention and treatment effects on diabetes, hyperlipidemia, atherosclerosis, Alzheimer's disease, cardiovascular and cerebrovascular diseases,inflammation, tumors and depression.
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- GLUCOSE TRIPTOLIDE CONJUGATES AND USES THEREOF
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A major hurdle in the treatment of cancer is chemoresistance induced under hypoxia that is characteristic of tumor microenvironment. Triptolide, a potent inhibitor of eukaryotic transcription, possesses potent antitumor activity. However, its clinical potential has been limited by toxicity and water solubility. To address those limitations of triptolide, the present disclosure designed and synthesized glucose-triptolide conjugates (glutriptolides) and demonstrated their antitumor activity in vitro and in vivo. The glutriptolides disclosed herein possess improved stability in human serum, greater selectivity towards cancer over normal cells and increased potency against cancer cells. Importantly, the glutriptolides are more potent against cancer cells under hypoxic conditions in contrast to existing cytotoxic drugs. These glutriptolides also exhibit sustained antitumor activity, prolonging survival in a prostate cancer metastasis animal model. Together, these findings suggest a new strategy to overcome chemoresistance through conjugation of cytotoxic agents to glucose.
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Paragraph 00298
(2021/09/11)
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- Chemical glucosylation of pyridoxine
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The chemical synthesis of pyridoxine-5′-β-D-glucoside (5′-β-PNG) was investigated using various glucoside donors and promoters. Hereby, the combination of α4,3-O-isopropylidene pyridoxine, glucose vested with different leaving and protecting groups and the application of stoichiometric amounts of different promoters was examined with regards to the preparation of the twofold protected PNG. Best results were obtained with 2,3,4,6-tetra-O-acetyl-D-glucopyranosyl fluoride and boron trifluoride etherate (2.0 eq.) as promoter at 0 °C (59%). The deprotection was accomplished stepwise with potassium/sodium hydroxide in acetonitrile/water followed by acid hydrolysis with formic acid resulting in the chemical synthesis of 5′-β-PNG.
- Bachmann, Thomas,Rychlik, Michael
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supporting information
(2020/02/13)
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- Ring Expansion Leads to a More Potent Analogue of Ipomoeassin F
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Two new ring-size-varying analogues (2 and 3) of ipomoeassin F were synthesized and evaluated. Improved cytotoxicity (IC50: from 1.8 nM) and in vitro protein translocation inhibition (IC50: 35 nM) derived from ring expansion imply that the binding pocket of Sec61α (isoform 1) can accommodate further structural modifications, likely in the fatty acid portion. Streamlined preparation of the key diol intermediate 5 enabled gram-scale production, allowing us to establish that ipomoeassin F is biologically active in vivo (MTD: μ3 mg/kg).
- Zong, Guanghui,Hu, Zhijian,Duah, Kwabena Baffour,Andrews, Lauren E.,Zhou, Jianhong,O'Keefe, Sarah,Whisenhunt, Lucas,Shim, Joong Sup,Du, Yuchun,High, Stephen,Shi, Wei Q.
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p. 16226 - 16235
(2020/12/22)
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- Enzyme-Catalyzed Regioselective Acetylation of Functionalized Glycosides
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Novozym 435 (N435) is an immobilized lipase (Candida antarctica lipase B) capable of catalyzing transesterfications in organic media. This paper describes how this enzyme can be used for regioselective acetylation of unprotected carbohydrates providing protected monosaccharide building blocks in only one step. Unprotected thiogylcosides with both gluco, xylo, and manno stereochemistry were tolerated by the enzyme and afforded the acetylated products in high yields. The regioselective acetylation was easily scaled up to a 5.0 gram scale and in most cases, no purification was needed. Several other glycosides, including 2-azido-2-deoxy glucosides, galactosides, and gluconolactones, were also acetylated and the scope and limitations using N435 has been uncovered.
- Holmstr?m, Thomas,Pedersen, Christian Marcus
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supporting information
p. 4612 - 4615
(2020/07/04)
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- One-Pot Relay Glycosylation
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A novel one-pot relay glycosylation has been established. The protocol is characterized by the construction of two glycosidic bonds with only one equivalent of triflic anhydride. This method capitalizes on the in situ generated cyclic-thiosulfonium ion as the relay activator, which directly activates the newly formed thioglycoside in one pot. A wide range of substrates are well-accommodated to furnish both linear and branched oligosaccharides. The synthetic utility and advantage of this method have been demonstrated by rapid access to naturally occurring phenylethanoid glycoside kankanoside F and resin glycoside merremoside D.
- Cai, Lei,Fang, Jing,Li, Ting,Song, Zejin,Sun, Jiuchang,Wan, Qian,Xiao, Xiong,Zeng, Jing
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supporting information
p. 5498 - 5503
(2020/04/09)
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- Synthesis of 12- O-Mono- and Diglycosyl-oxystearates, a New Class of Agonists for the C-type Lectin Receptor Mincle
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Fifteen glycosyl-oxystearates were synthesized by Crich's 4,6-benzylidene and K?ening-Knorr strategies. Assessment of structure-activity relationships using macrophage-inducible C-type lectin (Mincle) receptor cells expressing nuclear factor of activated
- Van Huy, Le,Tanaka, Chiaki,Imai, Takashi,Yamasaki, Sho,Miyamoto, Tomofumi
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supporting information
p. 44 - 49
(2019/01/15)
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- Visible Light Enables Aerobic Iodine Catalyzed Glycosylation
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A versatile protocol for light induced catalytic activation of thioglycosides using iodine as an inexpensive and readily available photocatalyst was developed. Oxygen serves as a green and cost-efficient terminal oxidant and irradiation is performed with a common household LED-bulb. The scope of this glycosylation protocol was investigated in the synthesis of O-glycosides with yields up to 95 %.
- Krumb, Matthias,Lucas, Tobias,Opatz, Till
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p. 4517 - 4521
(2019/08/06)
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- Preparation method of clostridium bolteae surface capsular polysaccharide structure derivative
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The invention discloses a preparation method of a clostridium bolteae surface capsular polysaccharide structure derivative and belongs to the field of sugar chemistry. The preparation method comprisesthe following steps: taking glucose as a glycosyl donor to obtain a target beta-glycosidic bond; then successfully synthesizing a disaccharide building block through an oxidization-reduction glucoseC-2 site method; then synthesizing a target oligosaccharide structure which takes the disaccharide building block as a repeating unit, such as the gram-positive bacterium surface capsular polysaccharide structure derivative [arrow3]-alpha-D-Manp-(1arrow4)-beta-D-Rhap-(1arrow]5-Linker. A reducing end of decaose is connected with a connecting arm and is used for connecting protein to form a glycoconjugate for carrying out immunology researches. The method provided by the invention has the advantages of simplicity, time saving, labor saving and low cost; the obtained clostridium bolteae surface capsular polysaccharide structure derivative is possibly used for developing and preparing medicine related to autism.
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- An Empirical Understanding of the Glycosylation Reaction
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Reliable glycosylation reactions that allow for the stereo- and regioselective installation of glycosidic linkages are paramount to the chemical synthesis of glycan chains. The stereoselectivity of glycosylations is exceedingly difficult to control due to the reaction's high degree of sensitivity and its shifting, simultaneous mechanistic pathways that are controlled by variables of unknown degree of influence, dominance, or interdependency. An automated platform was devised to quickly, reproducibly, and systematically screen glycosylations and thereby address this fundamental problem. Thirteen variables were investigated in as isolated a manner as possible, to identify and quantify inherent preferences of electrophilic glycosylating agents (glycosyl donors) and nucleophiles (glycosyl acceptors). Ways to enhance, suppress, or even override these preferences using judicious environmental conditions were discovered. Glycosylations involving two specific partners can be tuned to produce either 11:1 selectivity of one stereoisomer or 9:1 of the other by merely changing the reaction conditions.
- Chatterjee, Sourav,Moon, Sooyeon,Hentschel, Felix,Gilmore, Kerry,Seeberger, Peter H.
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p. 11942 - 11953
(2018/09/27)
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- Rapid Synthesis of l-Idosyl Glycosyl Donors from α-Thioglucosides for the Preparation of Heparin Disaccharides
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A new methodology for the synthesis of the most challenging heparin building block has been developed. Orthogonally protected l-idosyl glycosyl donors were prepared by C5 epimerization of the corresponding thioglucosides using the hydroboration/oxidation method followed by a 4,6-acetal formation. The α-anomeric configuration was crucial, and the bulky C4 substituent was advantageous for the high l-ido diastereoselectivity. The 4,6-arylmethylene group proved to be a directing element in glycosylation, whereby stereoselective α-idosylation could be achieved by using idosyl donors without a C-2 participating group.
- Herczeg, Mihály,Demeter, Fruzsina,Balogh, Tímea,Kelemen, Viktor,Borbás, Anikó
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p. 3312 - 3316
(2018/07/13)
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- A NOVEL SYNTHETIC NEISSERIA MENINGITIDIS SEROGROUP A OLIGOMER AND PROCESS FOR SYNTHESIZING THEREOF
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The present invention relates to novel synthetic Neisseria meningitidis Serogroup A (hereinafter MenA) capsular polysaccharide repeating unit oligomer and a process for synthesizing said synthetic MenA capsular polysaccharide repeating unit oligomer. More specifically, the present invention relates to the chemical synthesis of the tetramer of MenA capsular polysaccharide repeating unit capable of being used as a candidate in the development of semisynthetic or fully synthetic conjugate vaccines as monovalent or as a part of combination vaccines against Meningococcal serogroup A bacterial infection.
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- Synthesis of Azido-Glycans for Chemical Glycomodification of Proteins
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Chemically produced, accurately linkable oligosaccharides are of importance for the synthesis of neo-glycoproteins. On the route to high-mannose type N-glycans, we present a convenient synthesis of several glycans bearing an azide moiety at the reducing end. An azido-glycan core structure as valuable precursor was modified into the protected N-glycan pentasaccharide core structure and the possibility of modular attachment of different antenna was demonstrated through synthesis of a pentamannose donor and glycosylation with the core structure. The azido function allows for chemical ligation with recombinantly modified proteins featuring noncanonical cyclooctyne amino acids, providing access to customized glycopatterns of glycoproteins, e.g., of antibodies that are of high interest for biopharmaceutical applications.
- Wawryszyn, Mirella,Sauter, Paul F.,Nieger, Martin,Koos, Martin R. M.,Koehler, Christine,Luy, Burkhard,Lemke, Edward A.,Br?se, Stefan
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p. 4296 - 4305
(2018/08/29)
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- Synthesis and binding affinity analysis of α1-2- and α1-6-O/S-linked dimannosides for the elucidation of sulfur in glycosidic bonds using quartz crystal microbalance sensors
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The role of sulfur in glycosidic bonds has been evaluated using quartz crystal microbalance methodology. Synthetic routes towards α1-2- and α1-6-linked dimannosides with S- or O-glycosidic bonds have been developed, and the recognition properties assessed in competition binding assays with the cognate lectin concanavalin A. Mannose-presenting QCM sensors were produced using photoinitiated, nitrene-mediated immobilization methods, and the subsequent binding study was performed in an automated flow-through instrumentation, and correlated with data from isothermal titration calorimetry. The recorded Kd-values corresponded well with reported binding affinities for the O-linked dimannosides with affinities for the α1-2-linked dimannosides in the lower micromolar range. The S-linked analogs showed slightly disparate effects, where the α1-6-linked analog showed weaker affinity than the O-linked dimannoside, as well as positive apparent cooperativity, whereas the α1-2-analog displayed very similar binding compared to the O-linked structure.
- Norberg, Oscar,Wu, Bin,Thota, Niranjan,Ge, Jian-Tao,Fauquet, Germain,Saur, Ann-Kathrin,Aastrup, Teodor,Dong, Hai,Yan, Mingdi,Ramstr?m, Olof
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- Chemical Synthesis of Modified Hyaluronic Acid Disaccharides
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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
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p. 12283 - 12296
(2017/09/14)
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- Oxidative activation of C-S bonds with an electropositive nitrogen promoter enables orthogonal glycosylation of alkyl over phenyl thioglycosides
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A method for the selective activation of thioglycosides that uses the N+-thiophilic reagent Omesitylenesulfonylhydroxylamine (MSH) as a promoter is presented. The reaction proceeds via anomeric mesitylensulfonate intermediates, which could be isolated and fully characterized by placing a fluorine atom at the C2 position. In the presence of a soft Lewis acid, glycosylation reaction proceeds at ambient temperature with good yields. It is further demonstrated that it is possible to orthogonally activate S-ethyl in the presence of S-phenyl donors, enabling the design of sequential glycosylation strategies.
- Kitowski, Annabel,Jiménez-Moreno, Ester,Salvadó, Míriam,Mestre, Jordi,Castillón, Sergio,Jiménez-Osés, Gonzalo,Boutureira, Omar,Bernardes, Gon?alo J.L.
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p. 5490 - 5493
(2017/11/07)
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- Urea–hydrogen peroxide prompted the selective and controlled oxidation of thioglycosides into sulfoxides and sulfones
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A practical method for the selective and controlled oxidation of thioglycosides to corresponding glycosyl sulfoxides and sulfones is reported using urea–hydrogen peroxide (UHP). A wide range of glycosyl sulfoxides are selectively achieved using 1.5 equiv of UHP at 60 °C while corresponding sulfones are achieved using 2.5 equiv of UHP at 80 °C in acetic acid. Remarkably, oxidation susceptible olefin functional groups were found to be stable during the oxidation of sulfide.
- Singh, Adesh Kumar,Tiwari, Varsha,Mishra, Kunj Bihari,Gupta, Surabhi,Kandasamy, Jeyakumar
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p. 1139 - 1144
(2017/06/20)
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- Synthesis of the tetrasaccharide glycoside moiety of Solaradixine and rapid NMR-based structure verification using the program CASPER
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The major glycoalkaloid in the roots of Solanum laciniatum is Solaradixine having the branched tetrasaccharide β-d-Glcp-(1→2)-β-d-Glcp-(1→3)[α-l-Rhap-(1→2)]-β-d-Galp linked to O3 of the steroidal alkaloid Solasodine. We herein describe the synthesis of th
- Angles d'Ortoli, Thibault,Widmalm, G?ran
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p. 912 - 927
(2016/01/28)
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- Large-scale synthesis of 6-deoxy-6-sulfonatomethyl glycosides and their application for novel synthesis of a heparinoid pentasaccharide trisulfonic acid of anticoagulant activity
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Multigram-scale syntheses of three 6-deoxy-6-sulfonatomethyl α-glucosides were accomplished via reactions of the corresponding primary triflate derivatives with the lithiated ethyl methanesulfonate. Chemoselective glycosylation reactions of different 6-C-sulfonatomethyl glucoside donors were studied. The sulfonic acid-containing building blocks were utilised in a novel [2+3] block synthesis of a trisulfonic acid isoster of the anticoagulant pentasaccharide idraparinux.
- Mezo, Erika,Herczeg, Mihály,Eszenyi, Dániel,Borbás, Anikó
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- Exploring glycosylation reactions under continuous-flow conditions
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The industrial development of carbohydrate-based drugs is greatly thwarted by the typical challenges inherent in oligosaccharide synthesis. The practical advantages of continuous-flow synthesis in microreactors (high reproducibility, easy scalability, and fast reaction optimization) may offer an effective support to make carbohydrates more attractive targets for drug-discovery processes. Here we report a systematic exploration of the glycosylation reaction carried out under microfluidic conditions. Trichloroacetimidates and thioglycosides have been investigated as glycosyl donors, using both primary and secondary acceptors. Each microfluidic glycosylation has been compared with the corresponding batch reaction, in order to highlight advantages and drawbacks of microreactors technology. As a significant example of multistep continuous-flow synthesis, we also describe the preparation of a trisaccharide by means of two consecutive glycosylations performed in interconnected microreactors.
- Cancogni, Damiano,Lay, Luigi
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p. 2873 - 2878
(2015/01/16)
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- Synthesis of 6-sulfonatomethyl thioglycosides by nucleophilic substitution: Methods to prevent 1→6 anomeric group migration of thioglycoside 6-o-triflates
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Introduction of a sulfonatomethyl moiety into the primary position of thioglycosides by nucleophilic displacement of the corresponding 6-O-triflate is described. The 1→6 migration of the anomeric group, which inevitably occurs through a bicyclic sulfonium ion intermediate, from conformationally flexible β-thioglycosides was prevented by using an α-thioglycoside or conformationally locked β-thioglycoside as the starting material. The thioglycoside 6-sulfonic acids showed excellent α-selectivity during synthesis of uronic acid containing heparinoid trisaccharides. Two routes to prepare C6-sulfonatomethyl thioglucosides by displacement of a 6-O-triflate moiety are reported. The undesired participation of the β-thio aglycon is prevented by changing the anomeric configuration or by locking the pyranose ring. The 6-sulfonatomethyl donors show excellent α-selectivities but significantly different reactivities during the synthesis of heparinoid trisaccharides. Copyright
- Herczeg, Mihaly,Mezo, Erika,Eszenyi, Daniel,Lazar, Laszlo,Csavas, Magdolna,Bereczki, Ilona,Antus, Sandor,Borbas, Aniko
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p. 5570 - 5573
(2013/09/12)
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- 'Naked' and hydrated conformers of the conserved core pentasaccharide of N-linked glycoproteins and its building blocks
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N-glycosylation of eukaryotic proteins is widespread and vital to survival. The pentasaccharide unit -Man3GlcNAc2- lies at the protein-junction core of all oligosaccharides attached to asparagine side chains during this process. Although its absolute conservation implies an indispensable role, associated perhaps with its structure, its unbiased conformation and the potential modulating role of solvation are unknown; both have now been explored through a combination of synthesis, laser spectroscopy, and computation. The proximal -GlcNAc-GlcNAc- unit acts as a rigid rod, while the central, and unusual, -Man-β-1,4-GlcNAc- linkage is more flexible and is modulated by the distal Man-α-1,3- and Man-α-1,6- branching units. Solvation stiffens the 'rod' but leaves the distal residues flexible, through a β-Man pivot, ensuring anchored projection from the protein shell while allowing flexible interaction of the distal portion of N-glycosylation with bulk water and biomolecular assemblies.
- Barry, Conor S.,Cocinero, Emilio J.,Carcabal, Pierre,Gamblin, David P.,Stanca-Kaposta, E. Cristina,Remmert, Sarah M.,Fernandez-Alonso, Maria C.,Rudic, Svemir,Simons, John P.,Davis, Benjamin G.
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p. 16895 - 16903
(2013/12/04)
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- High-yield total synthesis of (-)-strictinin through intramolecular coupling of gallates
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This paper describes a total synthesis of (-)-strictinin, an ellagitannin that is 1-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl (HHDP)-β-d-glucose. In the study, total efficiency of the synthesis was improved to produce a 78% overall yield in 13 steps from d-glucose. In the synthesis, formation of the 4,6-(S)-HHDP bridge including the 11-membered bislactone ring was a key step, in which intramolecular aryl-aryl coupling was adopted. The coupling was oxidatively induced by CuCl2-n-BuNH2 with perfect control of the axial chirality, and the reaction conditions of this coupling were optimized thoroughly to achieve the quantitative formation of the bridge.
- Michihata, Naoki,Kaneko, Yuki,Kasai, Yusuke,Tanigawa, Kotaro,Hirokane, Tsukasa,Higasa, Sho,Yamada, Hidetoshi
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p. 4319 - 4328
(2013/06/27)
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- Studies on the substrate specificity of a GDP-mannose pyrophosphorylase from Salmonella enterica
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A series of methoxy and deoxy derivatives of mannopyranose-1-phosphate (Manp-1P) were chemically synthesized, and their ability to be converted into the corresponding guanosine diphosphate mannopyranose (GDP-Manp) analogues by a pyrophosphorylase (GDP-ManPP) from Salmonella enterica was studied. Evaluation of methoxy analogues demonstrated that GDP-ManPP is intolerant of bulky substituents at the C-2, C-3, and C-4 positions, in turn suggesting that these positions are buried inside the enzyme active site. Additionally, both the 6-methoxy and 6-deoxy Manp-1P derivatives are good or moderate substrates for GDP-ManPP, thus indicating that the C-6 hydroxy group of the Manp-1P substrate is not required for binding to the enzyme. When taken into consideration with other previously published work, it appears that this enzyme has potential utility for the chemoenzymatic synthesis of GDP-Manp analogues, which are useful probes for studying enzymes that employ this sugar nucleotide as a substrate.
- Zou, Lu,Zheng, Ruixiang Blake,Lowary, Todd L.
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supporting information; experimental part
p. 1219 - 1226
(2012/09/21)
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- Preparation of α- And β-D-glucoseptanose pentaacetates
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The α- and β-d-glucoseptanose pentaacetates have been prepared by treatment of ethyl 1-thio-β-d-glucoseptanoside tetraacetate with mercury(II) acetate in acetic acid. The solid state structure of the β-isomer has been determined by X-ray diffraction.
- Bhadbhade, Mohan,Craig, Donald C.,Ng, Clarence J.,Odier, Leon,Stevens, John D.
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- Contribution of phosphates and adenine to the potency of adenophostins at the IP3 receptor: Synthesis of all possible bisphosphates of adenophostin A
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Although adenophostin A (AdA), the most potent agonist of d-myo-inositol 1,4,5-trisphosphate receptors (IP3R), is thought to mimic IP 3, the relative roles of the different phosphate groups and the adenosine motif have not been established. We synthesized all three possible bisphosphate analogues of AdA and glucose 3,4-bisphosphate (7, AdA lacking the 2′-AMP). 2′-Dephospho-AdA (6) was prepared via a novel regioselective dephosphorylation strategy. Assessment of the abilities of these bisphosphates to stimulate intracellular Ca2+ release using recombinant rat type 1 IP3R (IP3R1) revealed that 6, a mimic of Ins(4,5)P2, is only 4-fold less potent than IP3, while 7 is some 400-fold weaker and even 3′3-dephospho-AdA (5) is measurably active, despite missing one of the vicinal bisphosphate groups normally thought to be crucial for IP3-like activity. Compound 6 is the most potent bisphosphate yet discovered with activity at IP3R. Thus, adenosine has a direct role independent of the 2′-phosphate group in contributing toward the potency of adenophostins, the vicinal bisphosphate motif is not essential for activity at the IP3R, as always thought, and it is possible to design potent agonists with just two of the three phosphates. A model with a possible adenine-R504 interaction supports the activity of 5 and 6 and also allows a reappraisal of the unexpected activity previously reported for the AdA regioisomer 2′3-phospho-3′3- dephospho-AdA 40.
- Sureshan, Kana M.,Riley, Andrew M.,Thomas, Mark P.,Tovey, Stephen C.,Taylor, Colin W.,Potter, Barry V. L.
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supporting information; experimental part
p. 1706 - 1720
(2012/05/04)
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- GLYCOMIMETIC COMPOUNDS AND METHODS TO INHIBIT INFECTION BY HIV
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Compounds, compositions and methods are provided for use to inhibit infection by human immunodeficiency virus (HIV). More specifically, the present invention relates to glycomimetic compounds that inhibit HIV infection, and uses thereof.
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- Synthesis of a glycodendrimer incorporating multiple mannosides on a glucoside core
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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.
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experimental part
p. 959 - 963
(2011/10/10)
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- Synthetic, structural, and biosynthetic studies of an unusual phospho-glycopeptide derived from α-dystroglycan
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Aberrant glycosylation of α-dystroglycan (α-DG) results in loss of interactions with the extracellular matrix and is central to the pathogenesis of several disorders. To examine protein glycosylation of α-DG, a facile synthetic approach has been developed for the preparation of unusual phosphorylated O-mannosyl glycopeptides derived from α-DG by a strategy in which properly protected phospho-mannosides are coupled with a Fmoc protected threonine derivative, followed by the use of the resulting derivatives in automated solid-phase glycopeptide synthesis using hyper-acid-sensitive Sieber amide resin. Synthetic efforts also provided a reduced phospho-trisaccharide, and the NMR data of this derivative confirmed the proper structural assignment of the unusual phospho-glycan structure. The glycopeptides made it possible to explore factors that regulate the elaboration of critical glycans. It was established that a glycopeptide having a 6-phospho-O-mannosyl residue is not an acceptor for action by the enzyme POMGnT1, which attaches β(1,2)-GlcNAc to O-mannosyl moietes, whereas the unphosphorylated derivate was readily extended by the enzyme. This finding implies a specific sequence of events in determining the structural fate of the O-glycan. It has also been found that the activity of POMGnT1 is dependent on the location of the acceptor site in the context of the underlying polypeptide/glycopeptide sequence. Conformational analysis by NMR has shown that the O-mannosyl modification does not exert major conformational effect on the peptide backbone. It is, however, proposed that these residues, introduced at the early stages of glycoprotein glycosylation, have an ability to regulate the loci of subsequent O-GalNAc additions, which do exert conformational effects. The studies show that through access to discrete glycopeptide structures, it is possible to reveal complex regulation of O-glycan processing on α-DG that has significant implications both for its normal post-translational maturation, and the mechanisms of the pathologies associated with hypoglycosylated α-DG.
- Mo, Kai-For,Fang, Tao,Stalnaker, Stephanie H.,Kirby, Pamela S.,Liu, Mian,Wells, Lance,Pierce, Michael,Live, David H.,Boons, Geert-Jan
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supporting information; experimental part
p. 14418 - 14430
(2011/10/19)
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- Preparation of Thiosugars and Their Use
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A process for the preparation of a thiosaccharide represented by Saccharide-S-H wherein Saccharide comprises at least 4 sugar units, comprises subjecting a corresponding compound of the formula (P)Saccharide-S-(P) wherein (P) represents an O- or S-protecting group(s), to Birch reduction.
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Page/Page column 7-8; 18
(2009/07/18)
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- Modular synthesis of heparan sulfate oligosaccharides for structure-activity relationship studies
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Although hundreds of heparan sulfate binding proteins have been identified and implicated in a myriad of physiological and pathological processes, very little information is known about the ligand requirements for binding and mediating biological activiti
- Arungundram, Sailaja,Al-Mafraji, Kanar,Asong, Jinkeng,Leach III, Franklin E.,Amster, I. Jonathan,Venot, Andre,Turnbull, Jeremy E.,Boons, Geert-Jan
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scheme or table
p. 17394 - 17405
(2010/03/23)
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- Synthesis and cytotoxicities of icogenin analogues with disaccharide residues
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For further structure-activity relationships (SAR) research of furostan saponin, two icogenin analogues: (25R)-22-O-methyl-furost-5-en-3β,26-diol-3-O-α-l-rhamnopyrano syl-(1 → 2)-β-d-glucopyranoside 1 and (25R)-22-O-methyl-furost-5-en-3β,26-diol-3-O-α-l-r
- Wang, Haixing,Su, Fuqin,Zhou, Liang,Chen, Xiaoguang,Lei, Pingsheng
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scheme or table
p. 2796 - 2800
(2010/04/05)
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- Synthesis of 2-(trimethylsilyl)ethyl α-D-mannopyranosides revisited
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Glycosylation of 2-(trimethylsilyl)ethanol with various ethyl 1-thioglycosides, which were activated with N-iodosuccinimide and silver triflate, was studied. The starting thioglycosides, some prepared for the first time, were obtained conventionally from the corresponding α-1-acetates. When β-1-acetates were more readily available, these were converted to the α-anomers by anomerization, prior to the glycosylation. Using ethyl 1-thioglycosides as glycosyl donors, especially those bearing a pivaloyl or a nonparticipating group at O-2, the corresponding 2-(trimethylsilyl)ethyl α-D-mannopyranosides were obtained in excellent yields.
- Saksena, Rina,Zhang, Jian,Kovac, Pavol
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p. 453 - 470
(2007/10/03)
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- Synthesis of three Salmonella epitopes for biosensor studies of carbohydrate-antibody interactions
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Disaccharides 1-3 corresponding to the antigenic determinants of Salmonella serotypes A, B, and D1 were synthesized in a form suited for use in biosensors. The disaccharide determinants each contain a unique 3,6-dideoxyhexose, namely abequose (
- Yu, Henry N.,Ling, Chang-Chun,Bundle, David R.
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p. 1131 - 1140
(2007/10/03)
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- Stereoselective synthesis of 2-S-ethyl(phenyl)-2-thio-β-glucopyranosides via 1,2-migration and concurrent glycosidation of ethyl(phenyl) 2,3-orthoester-1-thio-α-mannopyranosides
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1,2-Migration and concurrent glycosidation of ethyl(phenyl) 2,3-orthoester-1-thio-α-D- and L-mannopyranosides under the action of TMSOTf readily afforded the corresponding 2-S-ethyl(phenyl)-2-thio-β-glucopyranosides, ready precursors to 2-deoxy-arabino-hexopyranosides (2-deoxy-β-glucopyranosides).
- Yang, Zunyi,Yu, Biao
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p. 105 - 114
(2007/10/03)
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- Can preferential β-mannopyranoside formation with 4,6-O-benzylidene protected mannopyranosyl sulfoxides be reached with trichloroacetimidates?
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Studies with 3-O-allyl-2-O-benzyl-4,6-O-benzylidene-α-D-mannopyranosyl sulfoxide (3d) and the corresponding trichloroacetimidate (4) as glycosyl donors and various acceptors (A-F) led under similar reaction conditions to similar glycosylation results, i.e. mainly or exclusively the β-anomers of glycosides 5dA-5dF could be obtained. Thus, the versatile building block 5dA for N-glycan synthesis is readily available. For the activation of the sulfoxide leaving group, one equivalent of Tf2O and two equivalents of DTBMP are required, whereas for trichloroacetimidate activation catalytic amounts of TMSOTf are sufficient; hence, the trichloroacetimidate based procedure is very convenient. Various parameters were modified in the reaction of 4 with A (catalyst concentration, configuration of 4, size of the 2-O-protective group, solvent), thus, a proposal for the reaction course was derived. (C) 2000 Elsevier Science Ltd.
- Weingart,Schmidt
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p. 8753 - 8758
(2007/10/03)
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- Synthesis of a D,D- and L,D-heptose-containing hexasaccharide corresponding to a structure from Haemophilus ducreyi lipopolysaccharides
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The synthesis of a linear hexasaccharide, 2-(4-trifluoroacetamidophenyl)ethyl (β-D-galactopyranosyl)-(1→4)-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-(1→3)-(β-D-galactopyranosyl)-(1→4)-(D-glycero-α-D-manno-heptopyranosyl)-(1→6)-(β-D-glucopyranosyl)-(1→4)-L-
- Bernlind, Christian,Bennett, Simon,Oscarson, Stefan
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p. 481 - 492
(2007/10/03)
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- Investigations into the chemistry of some 1,6-epithio 1,6-episeleno β-D-glucopyranoses
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Derivatives of 1,6-dideoxy-1,6-epithio-β-D-glucopyranose have been shown to undergo oxidation reactions to afford the corresponding sulfoxides and sulfones. The sulfoxides participate in Pummerer reactions to afford the corresponding α-acetoxy sulfides wh
- Skelton, Brian W.,Stick, Robert V.,Tilbrook, D. Matthew G.,White, Allan H.,Williams, Spencer J.
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p. 389 - 397
(2007/10/03)
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- Synthesis of potent agonists of the D-myo-inositol 1,4,5-trisphosphate receptor based on clustered disaccharide polyphosphate analogues of adenophostin A
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Clustered disaccharide analogues of adenophostin A (2), i.e. mono-, di-, and tetravalent derivatives 6-8, respectively, were synthesized and evaluated as novel ligands for the tetrameric D-myo-inositol 1,4,5-trisphosphate receptor (IP3R). The s
- De Kort,Correa,Valentijn,Van der Marel,Potter,Taylor,Van Boom
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p. 3295 - 3303
(2007/10/03)
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- Synthesis of highly branched oligomannosides. 3. Synthesis of trityl ethers of mannobiosides and mannotriosides as precursors for higher mannooligosaccharides [1,2]
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Synthesis of mono- and ditrityl ethers of mannobiosides and mannotriosides as precursors for higher mannooligosaccharides is described. Advantage is taken of selective glycosylation of primary-secondary ditrityl ethers and selective removal of O-acetyl pr
- Backinowsky,Abronina,Nepogodiev,Grachev,Kochetkov
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p. 955 - 965
(2007/10/03)
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- Regioselective Lipase-catalysed acylation of 4,6-O-benzylidene-α- and - β-D-pyranoside derivatives displaying a range of anomeric substituents
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The application of Lipase enzymes to effect regioselective C-3-O- acylation of 4,6-O-benzylidene-β-D-gluco- and -galactopyranosides displaying a range of anomeric substituents, and C-2-O-acylation of phenyl 4,6-O- benzylidene-α-D-glucopyranoside and ethyl 4,6-O-benzylidene-1-thio-α-D- glucopyranoside is reported. In particular this method has allowed introduction of a variety of acyl protecting groups at the C-3 hydroxyl group of ethyl 4,6-O-benzylidene-1-thio-β-D-glucopyranoside 11.
- Gridley, Jonathan J.,Hacking, Andrew J.,Osborn, Helen M. I.,Spackman, David G.
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p. 14925 - 14946
(2007/10/03)
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- Synthesis of a trisaccharide fragment corresponding to the lipopolysaccharide region of vibrio parahaemolyticus
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Vicinal syn-dihydroxylation of D-manno-hept-6-enopyranosides 4 and 10 with OsO4 afforded D-glycero-α-D-manno-heptopyranosides 5 and 11, respectively, in good yield and with a high degree of stereoselectivity. Compound 5 was converted into DD-He
- Van Strafen,Kriek,Timmers,Wigchert,Van Der Marel,Van Boom
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p. 947 - 966
(2007/10/03)
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- Regioselective lipase-catalysed acylation of 4,6-O-benzylidene-β-D-pyranoside derivatives displaying a range of anomeric substituents
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The application of lipase enzymes to effect regioselective C-3-O-acylation of 4,6-O-benzylidene-β-D-gluco- and galactopyranosides displaying a range of anomeric substituents is reported. In particular this method has allowed introduction of a variety of acyl protecting groups at the C-3 hydroxyl group of ethyl 4,6-O-benzylidene-1-thio-β-D-glucopyranoside 9.
- Gridley, Jonathan J.,Hacking, Andrew J.,Osborn, Helen M. I.,Spackman, David G.
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p. 1397 - 1399
(2007/10/03)
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- Total synthesis of tricolorin A
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Tricolorin A (1), a structurally amazing resin glycoside with promising bioactivities from Ipomoea tricolor cav. (convolvulaceae), was synthesized in a total of 45 steps, with the longest linear sequence of 20 steps and overall yield of 0.65% from D-mannitol. The AB disscharide 19-membered lactone 2 was constructured by a regioselective macrolactonization using Corey-Nicolaou protocol. The macrolactone tetrasaccharide 33 was realized either by 'one- pot two-step' glycosylation procedure or by a stepwise assembly employing the 'armed-disarmed' glycosylation strategy.
- Lu, Shou-Fu,O'Yang, QinQin,Guo, Zhong-Wu,Yu, Biao,Hui, Yong-Zheng
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p. 8400 - 8405
(2007/10/03)
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- Chemoenzymatic synthesis of ethyl 1-thio-(β-D-galactopyranosyl)-O-β-D-glycopyranosyl disaccharides using the β-galactosidase from Bacillus circulans
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Different ethyl 1-thio-β-D-disaccharides have been synthesised by transgalactosylation using the β-galactosidase from Bacillus circulans as biocatalyst. This β-galactosidase shows mainly a β-1-4 specificity in the galactosyl transfer. Gal-β-(1-4)-O-β-D-GlcSEt 15 was obtained in 36% yield, Gal-β-(1-4)-O-α-D-GlcSEt 19 in 30% yield, Gal-β-(1-4)-O-β-D-GalSEt 17 in 60% yield, Gal-β-(1-4)-O-β-D-GalNAcSEt 20 in 49% yield, Gal-β-(1-4)-O-β-D-Gal-β-(1-4)-O-β-D-GalNAcSEt 21 in 9% yield, Gal-β-(1-6)-O-β-D-GlcSEt 16 in 3% yield and Gal-β-(1-3)-O-β-D-XylSEt 18 in 25% yield.
- Vic,Hastings,Howarth,Crout
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p. 709 - 720
(2007/10/03)
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- The Stereoselective Synthesis of Cyclomaltopentaose. A Novel Cyclodextrin Homologue with D.P. Five.
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A key intermediate 15 was prepared via successive glycosidations of 1,6-anhydro maltose derivative 8 with glycosyl donors 6 and then with 11, cyclized under a diluted condition, and deprotected to give the title compound.Every glycosidation, including the
- Nakagawa, Toshio,Ueno, Koji,Kashiwa, Mariko,Watanabe, Junko
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p. 1921 - 1924
(2007/10/02)
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- PARTIAL SUBSTITUTION OF THIOGLYCOSIDES BY PHASE TRANSFER CATALYZED BENZOYLATION AND BENZYLATION
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Partial substitution by phase transfer catalysis giving monobenzoylated and monobenzylated products from 2,3- and from 4,6-diols in ethyl 1-thio-D-hexopyranosides with the β-gluco, β-galacto- and α-manno-configurations are described.Two disaccharide thiog
- Garegg, Per J.,Kvarnstroem, Ingemar,Niklasson, Annika,Niklasson, Gunilla,Svensson, Stefan C. T.
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p. 933 - 954
(2007/10/02)
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- Synthesis of the laminara-oligosaccharide methyl β-glycosides of dp 3-8
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Ethyl 2,3,4,6-tetra-O-acetyl-1-thio-α-D-glucopyranoside has been prepared in a good yield by anomerization of the corresponding β-thioglucoside with tin(IV) chloride and transformed, in three steps, into ethyl 2-O-benzoyl-4,6-O-benzylidene-1-thio-α-D-glucopyranoside (18). Chloroacetylation of 18, followed by treatment of the product with chlorine gave crystalline 2-O-benzoyl-4,6-O-benzylidene-3-O-chloroacetyl-β-D-glucopyranosyl chloride (20). This was coupled with methanol in the presence of silver carbonate-silver perchlorate and the product was O-dechloroacetylated to afford methyl 2-O-benzoyl-4,6-O-benzylidene-β-D-glucopyranoside (22). Silver triflate-promoted glucosylation of 18 with 20 gave a β-(1 → 3)-linked disaccharide derivative, reaction of which with chlorine yielded crystalline O-(2-O-benzoyl-4,6-O-benzylidene-3-O-chloroacetyl-β-D-glucopyranosyl) -(1 → 3)-2-O-benzoyl-4,6-O-benzylidene-β-D-glucopyranosyl chloride (24). Likewise, condensation of 22 with 20 gave a β-(1 → 3)linked disaccharide glycoside, which was partially deprotected to give methyl O-(2-O-benzoyl-4,6-O-benzylidene-β-D-glucopyranosyl)-(1 → 3)-2-O-benzoyl-4,6-O-benzylidene-β-D-glucopyranoside (26). The methyl β-glycosides of a homologous series of (1 → 3)-linked β-D-gluco-oligosaccharides from the tri- to the octa-saccharide have been synthesized in a blockwise manner by using 22 and 26 as the glycosyl acceptors, 24 as the disaccharide donor, and silver triflate as the promoter. Ethyl 2,3,4,6-tetra-O-acetyl-1-thio-α-D-glucopyrano- side has been prepared in a good yield by anomerization of the corresponding B-thioglucoside with tin(IV) chloride and transformed, in three steps.
- Takeo,Maki,Wada,Kitamura
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