- 4,6-dideoxyglycosides, preparation method therefor and application of 4,6-dideoxyglycosides
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The invention discloses 4,6-dideoxypyranosides, a preparation method therefor and an application of the 4,6-dideoxypyranosides. The 4,6-dideoxypyranosides are prepared from rhamnose methylglycoside or mannose methylglycoside, which is cheap and readily available and serves as a starting raw material, through a simple and efficient reaction. An Orsellides C compound can be prepared through subjecting a D-type 4,6-dideoxypyranoside to a condensation reaction with 2,4-dihydroxyl-6-methyl benzoic acid in an organic solvent to form an ester bond. A condensation reaction system is DCC-DMAP or EDCI-DMAP, the use level of the condensation reaction system is 100% to 300% that of glycoside, a reaction solvent may be DMF, THF, CH2Cl2 or a mixed solvent of DMF-THF (v/v=1: 1), the reaction temperature is 20 DEG C to 80 DEG C, and the reaction time is 4 to 8 hours.
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Paragraph 0029; 0030; 0031
(2017/08/29)
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- Boronic esters as protective groups in carbohydrate chemistry: processes for acylation, silylation and alkylation of glycoside-derived boronates
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Procedures for selective installation of acyl, silyl ether and para-methoxybenzyl (PMB) ether groups to glycoside substrates have been developed, employing phenylboronic esters as protected intermediates. The sequence of boronic ester formation, functiona
- Mancini, Ross S.,Lee, Jessica B.,Taylor, Mark S.
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p. 132 - 143
(2016/12/27)
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- Enhanced site-selectivity in acylation reactions with substrate-optimized catalysts on solid supports
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A concept for site selective acylation of poly-hydroxylated substrates is presented where polymer-supported catalysts are employed: catalytically active DMAP units were combined with a library of small molecule peptides attached to the solid phase with the goal to identify substrate-optimized catalysts through library screening. For selected examples, we demonstrate how the optimized catalysts can convert “their” substrate with a markedly enhanced site-selectivity, compared to only DMAP. Due to the solid support, product purification is significantly simplified, and the peptidic catalysts can be easily reused in multiple cycles while conserving its efficiency.
- Tong, My Linh,Huber, Florian,Taghuo Kaptouom, Estelle S.,Cellnik, Torsten,Kirsch, Stefan F.
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p. 3086 - 3089
(2017/03/17)
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- Site-Selective Acylations with Tailor-Made Catalysts
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The acylation of alcohols catalyzed by N,N-dimethylamino pyridine (DMAP) is, despite its widespread use, sometimes confronted with substrate-specific problems: For example, target compounds with multiple hydroxy groups may show insufficient selectivity for one hydroxyl, and the resulting product mixtures are hardly separable. Here we describe a concept that aims at tailor-made catalysts for the site-specific acylation. To this end, we introduce a catalyst library where each entry is constructed by connecting a variable and readily tuned peptide scaffold with a catalytically active unit based on DMAP. For selected examples, we demonstrate how library screening leads to the identification of optimized catalysts, and the substrates of interest can be converted with a markedly enhanced site-selectivity compared with only DMAP. Furthermore, substrate-optimized catalysts of this type can be used to selectively convert "their" substrate in the presence of structurally similar compounds, an important requisite for reactions with mixtures of substances. Substrate-optimized catalysts: Site- selective acylations were achieved using substrate-optimized catalysts (see scheme) as identified from a library screening. The catalysts are composed of low-molecular-weight peptides that are readily tuned through variation of the amino acid sequence, and one amino acid was connected to DMAP to ensure catalytic activity. These substrate-optimized catalysts were also applied to selectively convert one substrate in the presence of a structurally similar compound.
- Huber, Florian,Kirsch, Stefan F.
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supporting information
p. 5914 - 5918
(2016/04/26)
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- Convergent synthesis of an octasaccharide fragment of the O-specific polysaccharide of Shigella dysenteriae type 1
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A stereocontrolled, convergent synthesis is described of the linear octasaccharide methyl glycoside α-L-Rhap-(1 -> 2)-α-D-Galp-(1 -> 3)-α-GlcpNAc-(1 -> 3)-α-L-Rhap-(1 -> 3)-α-L-Rhap-(1 -> 2)-α-D-Galp-(1 -> 3)-α-D-GlcpNAc-(1 -> 3)-α-L-Rhap-OMe (11), which
- Pozsgay, Vince,Pannell, Lewis
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p. 105 - 122
(2007/10/02)
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- SYNTHESIS OF THE O-SPECIFIC POLYSACCHARIDE OF SHIGELLA FLEXNERI
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A regular heteropolysaccharide built of tetrasaccharide repeating units is synthesised by means of regio- and stereospecific polycondensation of tritylated cyanoethylidene derivative.The polysaccharide obtained is identical with the O-antigenic polysaccharides of Shigella flexneri serotypes 3b, 3c, and variant Y.It also represents the basic chain of O-antigenic polysaccharides of all serotypes of this bacterium.
- Kotchekov, N. K.,Byramova, N. E.,Tsvetkov, Yu. E.,Backinowsky, L. V.
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p. 3363 - 3375
(2007/10/02)
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