- Efficient synthesis of α(1,2)-linked oligomannoside derivatives through one-pot glycosylation
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An α(1,2)-linked oligomannoside derivative having a free C-2 hydroxyl group and a C-3 pivaloyl group was synthesized from a thiophenyl mannose derivative 1 using a one-pot self-condensation and applying a α-stereoselective procedure. The mannosylation exclusively generated α-mannoside linkages. The observed α-directing effect was rationalized by the remote participation of the pivaloyl group in C-3 position. The polymerization degree was controlled by the promoter amount providing the mannobiose derivative as a major product. Applying this method eliminated many synthetic steps. The α(1,2)-linked oligomannoside derivatives, which are key intermediates for the synthesis of oligomannose type N-glycans for glycoproteins, were easily prepared.
- Ishii, Nozomi,Kosugi, Misa,Kuroiwa, Ayumi,Matsuo, Ichiro,Sano, Kanae
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- Synthesis and conformational analysis of phosphorylated β-(1→2) linked mannosides
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Phosphorylated β-(1→2)-oligomannosides are found on the cell surface of several Candida species, including Candida albicans (an opportunistic pathogen). These molecules are believed to take part in the invasion process of fungal infections, which in the case of C. albicans can lead to severe bloodstream infections and death, and can therefore be considered important from a biological standpoint. Understanding the mechanism of their action requires access to the corresponding oligosaccharide model compounds in pure form. In the present work, synthesis of the model core structures involved in the invasion process of C. albicans, consisting of phosphorylated β-(1→2)-linked mannotriose and tetraose, is reported. In order to elucidate the nature of these molecules in more detail, an extensive NMR-spectroscopic study encompassing complete spectral characterization, conformational analysis and molecular modelling was performed. The obtained results were also compared to similar chemical entities devoid of the charged phosphate group.
- Rahkila, Jani,Ekholm, Filip S.,Panchadhayee, Rajib,Arda, Ana,Canada, Francisco Javier,Jimenez-Barbero, Jesus,Leino, Reko
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- Synthesis of |β-(1→2)-linked oligomannosides
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β-(1→2)-Linked oligomannosides constitute an important class of carbohydrate structures located on the cell surface of several Candida species, including C. albicans. As a result of the immunostimulating properties of such compounds, the upscaling of their synthesis is relevant. In this paper, a highly stereoselective synthesis of |β-(1→2)-linked oligomannosides was performed by further development of and modifications to the methodologies described earlier in the literature. In addition to the synthesis of fully deprotected β-(1→2)-linked mannobiose and mannotriose, some preliminary modifications to the oligosaccharide core, resulting in close analogues with biological potential, are presented. The fully deprotected products form potential targets for screening against C. albicans and may also result in new model structures for vaccine development.
- Polakova, Monika,Roslund, Mattias U.,Ekholm, Filip S.,Saloranta, Tiina,Leino, Reko
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p. 870 - 888
(2009/07/17)
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- Synthetic analogues of beta-1,2 oligomannosides prevent intestinal colonization by the pathogenic yeast Candida albicans.
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The pathogenic yeast Candida albicans displays at its cell surface beta-1,2 oligomannosides (beta-1,2-Mans). In contrast to the ubiquitous alpha-Mans, beta-1,2-Mans bind to galectin-3, a major endogenous lectin expressed on epithelial cells. The specific
- Dromer, Francoise,Chevalier, Reynald,Sendid, Boualem,Improvisi, Luce,Jouault, Thierry,Robert, Raymond,Mallet, Jean Maurice,Poulain, Daniel
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p. 3869 - 3876
(2007/10/03)
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