- N-Glycosylation reactions in the solid to solid state
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The solid to solid sstate reactions of glycopyranosyl bromide silylated uracil or thymine in the presence of silver trifluoroacetate provided glycopyranosyl uracil or thymine with an excellent stereoselectivity.
- Im, Juwon,Kim, Jaechul,Kim, Sukjin,Hahn, Bosup,Toda, Fumio
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- Synthesis of pyranonucleoside-6′-triphosphates through the cyclosal-method
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The high yielding synthesis of pyranonucleoside-6′-triphosphates by using the cycloSal-method is described. Synthesis of the activated cycloSal-pyranonucleoside-6′-phosphate triesters was achieved by applying a synthetic route that had been developed for the synthesis of cycloSal-(glycopyranosyl-6)-phosphates by us. The route involved regioselective 6′-tert-butyldimethylsilyl protection and exchange of the silyl protecting group by the fluorenylmethyloxycarbonyl (Fmoc) group. The 6′-Fmoc- protected derivatives were selectively converted into the cycloSal-triester. These were then very efficiently converted into triphosphates by a "titration-like" reaction with pyrophosphate. Simple purification by first ion exchange followed by reversed phase (RP) column chromatography afforded the triphosphates in very good yields. Copyright
- Huchting, Johanna,Meier, Chris
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- NIS/TMSOTf-Promoted Glycosidation of Glycosyl ortho-Hexynylbenzoates for Versatile Synthesis of O-Glycosides and Nucleosides
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Glycosidation plays a pivotal role in the synthesis of O-glycosides and nucleosides that mediate a diverse range of biological processes. However, efficient glycosidation approach for the synthesis of both O-glycosides and nucleosides remains challenging in terms of glycosidation yields, mild reaction conditions, readily available glycosyl donors, and cheap promoters. Here, we report a versatile N-iodosuccinimide/trimethylsilyl triflate (NIS/TMSOTf)-promoted glycosidation approach with glycosyl ortho-hexynylbenzoates as donors for the highly efficient synthesis of O-glycosides and nucleosides. The glycosidation approach highlights the merits of mild reaction conditions, cheap promoters, extremely wide substrate scope, and good to excellent yields. Notably, the glycosidation approach performs very well in the construction of a series of challenging O- and N-glycosidic linkages. The glycosidation approach is then applied to the efficient synthesis of oligosaccharides via the one-pot strategy and the stepwise strategy. On the basis of the isolation and characterization of the departure species derived from the leaving group, a plausible mechanism of NIS/TMSOTf-promoted glycosidation of glycosyl ortho-hexynylbenzoates is proposed.
- Liu, Rongkun,Hua, Qingting,Lou, Qixin,Wang, Jiazhe,Li, Xiaona,Ma, Zhi,Yang, You
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p. 4763 - 4778
(2021/04/06)
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- SELECTIVE VALORIZATION OF BIOMASS SUGARS
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Disclosed are methods of forming an epimer or a dehydrated isomer of a pyranose monosaccharide or a pyranose saccharide residue in an oligosaccharide or a glycoside.
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Page/Page column 23; 31
(2021/06/26)
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- Effective synthesis of nucleosides utilizing O-acetyl-glycosyl chlorides as glycosyl donors in the absence of catalyst: Mechanism revision and application to silyl-hilbert-johnson reaction
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An effective synthesis of nucleosides using glycosyl chlorides as glycosyl donors in the absence of Lewis acid has been developed. Glycosyl chlorides have been shown to be pivotal intermediates in the classical silyl-Hilbert-Johnson reaction. A possible mechanism that differs from the currently accepted mechanism advanced by Vorbrueggen has been proposed and verified by experiments. In practice, this catalyst-free method provides easy access to Capecitabine in high yield.
- Liang, Chengyuan,Ju, Weihui,Ding, Shunjun,Sun, Han,Mao, Gennian
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- A general method for N-glycosylation of nucleobases promoted by (p-Tol)2SO/Tf2O with thioglycoside as donor
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Based on a preactivation strategy using the (p-Tol)2SO/Tf2O system, a series of nucleosides were synthesized by coupling various thioglycosides with pyrimidines and purines under mild conditions. High yields and excellent β-stereoselectivities were obtained with either armed or disarmed N-glycosylation donors by tuning the amount of (p-Tol)2SO additive.
- Liu, Guang-Jian,Zhang, Xiao-Tai,Xing, Guo-Wen
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p. 12803 - 12806
(2015/08/06)
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- An efficient approach to the synthesis of nucleosides: Gold(I)-catalyzed N-glycosylation of pyrimidines and purines with glycosyl ortho-alkynyl benzoates
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Persuaded with gold: The title reaction in the presence of [Ph 3PAuNTf2] (Tf=trifluoromethanesulfonyl) led conveniently to the corresponding nucleosides with excellent regioselectivity (see scheme). Even purine derivatives underwent this transformation owing to the mild conditions, which enabled the use of protecting groups that would not usually be compatible with N-glycosylation conditions. Copyright
- Zhang, Qingju,Sun, Jiansong,Zhu, Yugen,Zhang, Fuyi,Yu, Biao
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supporting information; experimental part
p. 4933 - 4936
(2011/06/24)
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- An improved procedure for nucleoside synthesis using glycosyl trifluoroacetimidates as donors
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Using glycosyl trifluoroacetimidates as donors and nitromethane (or acetonitrile) as solvent, silylation and subsequent glycosylation were realized in a 'one-pot' procedure to provide the corresponding nucleosides derivatives in high yields.{A figure is p
- Liao, Jinxi,Sun, Jiansong,Yu, Biao
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experimental part
p. 1034 - 1038
(2009/09/05)
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- Effective synthesis of nucleosides with glycosyl trifluoroacetimidates as donors
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Glycosyl trifluoroacetimidates have been disclosed to be effective glycosyl donors for the synthesis of nucleosides; the present N-glycosylation protocol requires only a catalytic amount of TMSOTf as promoter and proceeds smoothly at room temperature.
- Liao, Jinxi,Sun, Jiansong,Yu, Biao
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p. 5036 - 5038
(2008/12/21)
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- Oligodeoxyribonucleosides containing 1-β-D-glucopyranosylthymine: Synthesis and substrate properties
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Regioselective method for 1-β-D-glucopyranosylthymine incorporation into oligonucleotides has been developed and substrate properties of the latters in DNA synthesis and hydrolysis reactions were investigated.
- Ermolinsky, Boris S.,Fomitcheva, Marina V.,Efimtseva, Ekaterina,Meshkov, Sergey E.,Mikhailov, Sergey N.,Esipov, Dmitriy S.,Boldyreva, Elena F.,Korobko, Vyacheslav G.
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p. 1619 - 1634
(2007/10/03)
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