Cyclooligomerisation of azido-alkyne-functionalised sugars: synthesis of 1,6-linked cyclic pseudo-galactooligosaccharides and assessment of their sialylation by Trypanosoma cruzi trans-sialidase
Cyclooligomerisation of azido-alkyne-functionalised sugars: synthesis of 1,6-linked cyclic pseudo-galactooligosaccharides and assessment of their sialylation by Trypanosoma cruzi trans-sialidase
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DOI：
10.1039/c0sc00301h
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发表时间：
2010-10-01
期刊：
影响因子：
8.4
通讯作者：
Field, Robert A.
中科院分区：
文献类型：
--
作者：
Campo, Vanessa L.;Carvalho, Ivone;Field, Robert A.
在Cu(I)催化叠氮化物-炔烃1,3偶极环加成反应条件下，以β -d -半乳糖醛酸为原料，由叠氮化物-炔烃异构体衍生物进行环寡聚反应合成环状伪半乳糖低聚糖。分离的主要产物是环二聚体和三聚体，在某些情况下，环四聚体和五聚体的含量也较低。分子力学计算表明，环三聚体的结构非常紧凑但灵活，二级羟基暴露在大环外，可用于酶糖基化。环状二聚体和三聚体代表了克氏锥虫反式唾液酸酶的一种新型受体底物，分别产生双重和三重唾液酸糖大环。
Cyclic pseudo-galactooligosaccharides were synthesized by cyclooligomerisation of isomeric azido-alkyne derivatives of beta-D-galactopyranose under Cu(I)-catalysed azide-alkyne 1,3-dipolar cycloaddition reaction conditions. The principal products isolated were cyclic dimers and trimers, with lower amounts of cyclic tetramer and pentamer also evident in some cases. Molecular mechanics calculations suggest very compact but flexible structures for the cyclic trimers, with secondary OH groups exposed outside the macrocycle and available for enzymatic glycosylation. The cyclic dimers and trimers represent a new type of acceptor substrate for Trypanosoma cruzi trans-sialidase, giving rise to doubly and triply sialylated glycomacrocycles, respectively.