Synthesis of β‐(1→2)‐Linked Oligomannosides

Abstract

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.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Chemical Synthesis of Modified Hyaluronic Acid Disaccharides

“…The highest yield (64 %) was achieved starting from α‐bromide 4 using indium(III) chloride as activator; under the same conditions the α‐iodide 2 gave a yield of 22 %. Direct glycosylation of the peracetylated d ‐glucose 3 under BF 3 ⋅ OEt 2 activation gave a yield of 4.8 %, which revealed that glucose derivatives, in comparison with the corresponding mannosides, are not suitable for such transformations …”

“…Direct glycosylation of the peracetylated d-glucose 3 under BF 3 ·OEt 2 activation gave ay ield of 4.8 %, which revealed that glucose derivatives, in comparison with the corresponding mannosides, are not suitable for such transformations. [18] Thioethers are very convenient compounds for glycosylation strategies, because at hioether group connected to an anomeric center can serve both as at emporary protecting group and as an activatable group for glycosylation reactions. Thus, we synthesized the two b-thioethers 6 and 7 under different conditions.…”

Evaluation of Immunostimulatory Activities of Synthetic Mannose-Containing Structures Mimicking the β-(1→2)-Linked Cell Wall Mannans of Candida albicans

“…1A, 2A, 3A, and 4A), were prepared by applying and further modifying the recently developed methodologies for construction of ␤-(1¡2)-mannosidic linkages by Crich and others (7). The synthesis procedures have been published previously by us (9,10,28). The compounds prepared were designed as simple mimics and analogues of the hydrolyzed oligosaccharide fractions from the C. albicans cell wall, with the ␤-(1¡2) linkage serving as a basis for all structural modifications.…”

Rate‐Dependent Inverse‐Addition β‐Selective Mannosylation and Contiguous Sequential Glycosylation Involving β‐Mannosidic Bond Formation

“…Since disaccharides 3α , 3β , 18 ,9c 19 ,9a 21 , and 22 are potential glycosyl donors, it is necessary to confirm their structures for future applications. Thus, all these disaccharides were rigorously characterized by NMR spectroscopy and selected characteristic data are depicted in Table 4.…”