			Home About us Contact

Glycosylation Reaction (glycosylation + reaction)

Distribution by Scientific Domains

Chemistry	90%

Selected Abstracts

Computational Insight into the Reaction Intermediates in the Glycosylation Reaction Assisted by Donor Heteroatoms.

CHEMINFORM, Issue 20 2003
Fernando Bravo
No abstract is available for this article. [source]

Stereoselective Synthesis of 2-Deoxyglycosides from Sulfanyl Alkenes by Consecutive "One Pot" Cyclization and Glycosylation Reactions

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 15 2007
Miguel A. Rodríguez
Abstract 2-Deoxy-2-iodopyranosides 3, and 9,12 were synthesized from sulfanyl alkenes using a "one pot" consecutive cyclization,glycosylation process. Compared with the stepwise procedure, the "one pot" process gave significantly improved yields with similar or slightly lower selectivities. The "onepot" procedure was applied to the synthesis of 2,6-dideoxy-2-iodoglycoside 22, which was successfully deiodinated to afford the 2,6-dideoxyglycoside 23. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

Optimization of Glycosylation Reactions in a Microreactor.

CHEMINFORM, Issue 24 2007
Karolin Geyer
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

A Study on the Influence of the Structure of the Glycosyl Acceptors on the Stereochemistry of the Glycosylation Reactions with 2-Azido-2-Deoxy-Hexopyranosyl Trichloroacetimidates

CHEMISTRY - A EUROPEAN JOURNAL, Issue 3 2005
M. Belén Cid Dr.
Abstract The stereochemical outcome of glycosylations with 2-azido-2-deoxy- D -gluco- and D -galactopyranosyl trichloroacetimidates as glycosyl donors has been investigated by using a series of chiro -inositol derivatives as glycosyl acceptors. The influence of the absolute configuration, the conformation and the conformational flexibility of the glycosyl acceptor has been studied by using different glycosyl donors under similar pre-established experimental conditions. Although the structure of the acceptor may play a role in governing the stereochemistry of these glycosylations, the results show that, in general terms, the relative influence of these factors is difficult to evaluate. For a given set of experimental conditions, the stereochemical course of these glycosylations depends on structural features of both glycosyl donor and glycosyl acceptor. It is a balance of these factors, where the structure of the glycosyl donor always plays a major role, which determines the stereochemistry of the coupling reaction. Therefore, the examples reported in the literature in which the structure of the glycosyl acceptor appears to be crucial in determining the stereochemistry of the reaction constitute particularly favorable cases which do not presently allow any further generalization. [source]

Efficient Synthesis of ,-Glycosphingolipids by Reaction of Stannylceramides with Glycosyl Iodides Promoted by TBAI/AW 300 Molecular Sieves

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 23 2009
José Antonio Morales-Serna
Abstract TBAI and acid-washed molecular sieves efficiently promoted the glycosylation of stannylceramides with glycosyl iodides. This direct glycosylation reaction reduces the overall number of synthetic steps and provides rapid access to ,-glycosphingolipids such as GalCer, ,-lactosylceramide, and iGB3 in good yield and with complete chemo- and stereoselectivity. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

Glycosylations Directed by the Armed-Disarmed Effect with Acceptors Containing a Single Ester Group

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 23 2007
Thomas H. Schmidt
Abstract A selective glycosylation reaction controlled by the armed-disarmed effect is described by the use of phenyl thioglycosides. The donor thioglycoside is fully protected with benzyl ethers while the acceptor thioglycoside contains benzyl ethers at position 2 and 3 and a strongly electron-withdrawing pentafluorobenzoate ester group at position 6. The coupling can be performed with galactose, glucose, mannose, and phthalimide-protected glucosamine to afford the corresponding 1,4-linked disaccharides in good yield. These disaccharides can act as glycosyl donors for an additional coupling reaction in the same pot if another acceptor and more promoter are added. In this way, two consecutiveglycosylations can be achieved to afford trisaccharides in one operation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

Low-Concentration 1,2- trans ,-Selective Glycosylation Strategy and Its Applications in Oligosaccharide Synthesis

CHEMISTRY - A EUROPEAN JOURNAL, Issue 41 2009
Chin-Sheng Chao
Abstract This study develops an operationally easy, efficient, and general 1,2- trans ,-selective glycosylation reaction that proceeds in the absence of a C2 acyl function. This process employs chemically stable thioglycosyl donors and low substrate concentrations to achieve excellent ,-selectivities in glycosylation reactions. This method is widely applicable to a range of glycosyl substrates irrespective of their structures and hydroxyl-protecting functions. This low-concentration 1,2- trans ,-selective glycosylation in carbohydrate chemistry removes the restriction of using highly reactive thioglycosides to construct 1,2- trans ,-glycosidic bonds. This is beneficial to the design of new strategies for oligosaccharide synthesis, as illustrated in the preparation of the biologically relevant ,-(1,6)-glucan trisaccharide, ,-linked Gb3 and isoGb3 derivatives. [source]

Synthesis of 2-C-Branched Oligo(glyco,amino acid)s (OGAAs) by Ring Opening of 1,2-Cyclopropanecarboxylated Sugar Donors

CHEMISTRY - A EUROPEAN JOURNAL, Issue 31 2009
Perali, Ramu Sridhar Dr.
Hybrid theory: 1,2-Cyclopropanecarboxylated sugars were used as glycosyl donors for the first time in the synthesis of 2-C-branched oligo(glyco,amino acid)s (OGAAs; see scheme) decorated with ,-amino acids. The method was applied to an acceptor-reactivity-based stereo- and regioselective glycosylation reaction towards the preparation of several disaccharide-derived glyco,amino acid derivatives. [source]

Enzymatic production of ,- D -glucose-1-phosphate from trehalose

BIOTECHNOLOGY JOURNAL, Issue 9 2010
Jef Van der Borght
Abstract ,- D -Glucose-1-phosphate (,Glc1P) is an efficient glucosyl donor for both enzymatic and chemical glycosylation reactions but is currently very costly and not available in large amounts. This article provides an efficient production method of ,Glc1P from trehalose and phosphate using the thermostable trehalose phosphorylase from Thermoanaerobacter brockii. At the process temperature of 60°C, Escherichia coli expression host cells are lysed and cell treatment prior to the reaction is, therefore, not required. In this way, the theoretical maximum yield of 26% could be easily achieved. Two different purification strategies have been compared, anion exchange chromatography or carbohydrate removal by treatment with trehalase and yeast, followed by chemical phosphate precipitation. In a next step, ,Glc1P was precipitated with ethanol but this did not induce crystallization, in contrast to what is observed with other glycosylphosphates. After conversion of the product to its cyclohexylammonium salt, however, crystals could be readily obtained. Although both purification methods were quantitative (>99% recovery), a large amount of product (50%) was lost during crystallization. Nevertheless, a production process for crystalline ,Glc1P is now available from the cheap substrates trehalose and inorganic phosphate. [source]

Glycosyltransferases and their Assays

CHEMBIOCHEM, Issue 14 2010
Dr. Gerd K. Wagner
Abstract Glycosyltransferases (GTs) are a large family of enzymes that are essential in all domains of life for the biosynthesis of complex carbohydrates and glycoconjugates. GTs catalyse the transfer of a sugar from a glycosyl donor to a variety of acceptor molecules, for example, oligosaccharides, peptides, lipids or small molecules. Such glycosylation reactions are central to many fundamental biological processes, including cellular adhesion, cell signalling and bacterial- and plant-cell-wall biosynthesis. GTs are therefore of significant interest as molecular targets in chemical biology and drug discovery. In addition, GTs have found wide application as synthetic tools for the preparation of complex carbohydrates and glycoconjugates. In order to exploit the potential of GTs both as molecular targets and synthetic tools, robust and operationally simple bioassays are essential, especially as more and more protein sequences with putative GT activity but unknown biochemical function are being identified. In this minireview, we give a brief introduction to GT biochemistry and biology. We outline the relevance of GTs for medicinal chemistry and chemical biology, and describe selected examples for recently developed GT bioassays, with a particular emphasis on fluorescence-based formats. [source]