Synthesis of Branched Mannose Oligosaccharides by Using a Consecutive Orthogonal Protection Method
Date Issued
2013
Date
2013
Author(s)
Chang, Sue-Ming
Abstract
N-Glycans play an important role in numerous biological activities, such as immunity, pathogen-host interaction and cancer metastasis. Their syntheses represent a great challenge in a carbohydrate chemistry because the structures of N-glycans are often complicated by the presence of branching structures and various modifications in the non-reducing termini (e.g. sulfation, fucosylation and sialylation). It is thus indispensible to develop a simple but versatile approach that is applicable to the preparation of most N-glycans.
This thesis aims at the synthesis of biatennary N-acetyl lactosamine attached to the trimammose core via β1-6 linkage, and futher introduction of sulfate group and L-fucose residues to the non-reducing end. We developed a facile method to prepare orthogonally protected mannose building blocks, make it to carry out consecutive protection/glycosylation steps with high overall yields without the necessity of purification of products. This developed procedure led to the formation of linear/branched tri -(26, 30, 37 and 40), penta-(28) and heptasaccharides (46). Further deprotection, sulfation and/or enzymatic fucosylation steps led to formation of several hepta- and nonasaccharides that were subjected to the binding assay of human galectin-7.With these saccharides available, we are able to address important features of galectin-7 binding affinity, such as linear and branched structures, the effect of sulfation or fucosylation.
Subjects
甘露醣
正交錯保護
SDGs
Type
thesis
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