- Synthesis and reactivity of 4'-deoxypentenosyl disaccharides
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4-Deoxypentenosides (4-DPs) are versatile synthons for rare or higher-order pyranosides, and they provide an entry for structural diversification at the C5 position. Previous studies have shown that 4-DPs undergo stereocontrolled DMDO oxidation; subsequent epoxide ring-openings with various nucleophiles can proceed with both anti or syn selectivity. Here, we report the synthesis of α- and β-linked 4'-deoxypentenosyl (4'-DP) disaccharides, and we investigate their post-glycosylational C5' additions using the DMDO oxidation/ring-opening sequence. The α-linked 4'-DP disaccharides were synthesized by coupling thiophenyl 4-DP donors with glycosyl acceptors using BSP/Tf2O activation, whereas β-linked 4'-DP disaccharides were generated by the decarboxylative elimination of glucuronyl disaccharides under microwave conditions. Both α- and β-linked 4'-DP disaccharides could be epoxidized with high stereoselectivity using DMDO. In some cases, the α-epoxypentenosides could be successfully converted into terminal l-iduronic acids via the syn addition of 2-furylzinc bromide. These studies support a novel approach to oligosaccharide synthesis, in which the stereochemical configuration of the terminal 4'-DP unit is established at a post-glycosylative stage.
- Padungros, Panuwat,Fan, Ren-Hua,Casselman, Matthew D.,Cheng, Gang,Khatri, Hari R.,Wei, Alexander
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p. 4878 - 4891
(2014/06/23)
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- Synthesis and evaluation of 2-deoxy-2-amino-β-cellobiosides as cellulase inhibitors
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The cellulase mixture of Hypocrea jecorina (formerly Trichoderma reesei) contains a variety of exo- and endoglucanases that belong to different structural families. As such, these enzymes form an interesting model system to study the enzyme-ligand interac
- Desmet, Tom,Claeyssens, Marc,Piens, Kathleen,Nerinckx, Wim
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p. 164 - 180
(2011/06/19)
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- Simple preparations of alkyl and cycloalkyl α-glycosides of maltose, cellobiose, and lactose
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Alkyl, cycloalkyl, allyl, 4-pentenyl, and benzyl α-glycosides of maltose, cellobiose, and lactose were prepared via direct reaction of the free bioses with a binary AcBr-AcOH system, followed by glycosidation with alcohol using FeCl3 in MeNO2 or CH2Cl2, Zemple?n deacetylation, and the chromatographic resolution of the mixture. The respective β-biosides were obtained via the glycosidation in MeCN. Alkyl, cycloalkyl, allyl, 4-pentenyl, and benzyl α-glycosides of maltose, cellobiose, and lactose were prepared (17-77% yield; α/β = 70/30-96/4) via a direct reaction of the free disaccharides with a binary AcBr-AcOH mixture, followed by glycosidation with alcohol using FeCl3 in MeNO2 or CH2Cl2, Zemple?n deacetylation, and resolution of the anomeric mixture of glycosides by chromatography. Using MeCN as solvent for the glycosidation step, the corresponding β-biosides were also prepared (16-61% yield; α/β = 25/75-5/95).
- Koto, Shinkiti,Hirooka, Motoko,Tashiro, Takako,Sakashita, Motokazu,Hatachi, Masaharu,Kono, Takayuki,Shimizu, Miho,Yoshida, Nahoko,Kurasawa, Sayaka,Sakuma, Natsuko,Sawazaki, Sunao,Takeuchi, Akihiro,Shoya, Naomi,Nakamura, Emi
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p. 2415 - 2424
(2007/10/03)
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- The chemical synthesis of beta-(1-->4)-linked D-mannobiose and D-mannotriose.
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A D-cellobiose derivative was converted to D-mannobiose via simultaneous epimerization at C-2 and C-2'. Subsequent beta-D-glucosylation and epimerization at C-2" gave D-mannotriose.
- Twaddle, Gavin W,Yashunsky, Dmitry V,Nikolaev, Andrei V
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p. 623 - 628
(2007/10/03)
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