Aldolase-Catalyzed Synthesis of β-d-Galp-(1→9)-d-KDN: A Novel Acceptor for Sialyltransferases
摘要:
[graphics]beta-D-Galp-(1 -> 9)-D-KDN, a disaccharide component of the cell wall of Streptomyces sp. MB-8, was synthesized from beta-D-Galp-(1 -> 6)-D-Manp and pyruvate using a sialic acid aldolase. The obtained KDN-containing compound was a novel acceptor for bacterial sialyltransferases. Unusual alpha 2,3- and alpha 2,6-linked sialyltrisaccharides and a tetrasaccharide were synthesized using a one-pot two-enzyme system containing a Neisseria meningitidis CMP-sialic acid synthetase and a Pasteurella multocida sialyltransferase or a Photobacterium damsela alpha 2,6-sialyltransferase.
An efficient ionic liquid-supported oligosaccharidesynthesis (ILSOS) strategy was described for the synthesis of linear oligo-phosphomannan. A new cleavable benzyl carbamate-type IL supporter containing 5-aminopentanyl linker was designed as an acceptor IL tag to facilitate this synthesis. The chain elongation on IL tag was achieved by H-phosphonate chemistry, including condensation with α-mannosyl
描述了一种有效的离子液体支持的寡糖合成 (ILSOS) 策略,用于合成线性寡聚-磷酸甘露聚糖。含有 5-氨基戊基接头的新型可裂解氨基甲酸苄酯型 IL 支持物被设计为受体 IL 标签以促进该合成。IL 标签上的链延长是通过 H-膦酸酯化学实现的,包括与 α-甘露糖基 H-膦酸酯缩合、原位氧化反应和随后的脱保护。四个循环后,45小时内得到线性α-(1→6)-四甘露聚糖磷酸酯,总产率为52.7%。IL 标记的产品在极性和非极性溶剂系统中表现出可调的溶解度,这有助于组装过程中的无色谱纯化。在最后一步氢解处理后,IL标签可以很容易地去除,在磷酸聚糖的还原端提供一个胺封端的接头,用于进一步与载体蛋白结合。该方法为合成磷酸聚糖提供了一种高效且无需色谱的方法。
Facile synthesis of a comb-like mannohexaose: a trimer of the disaccharide repeating unit of the cell-wall mannans of Aphanoascus mephitatus and related species
作者:Linsen Heng、Jun Ning、Fanzuo Kong
DOI:10.1016/s0008-6215(01)00059-3
日期:2001.4
An efficient method for the preparation of a comb-like mannohexaose having alpha-(1-->6) and alpha-(1-->2) linkages has been described using 6-O-acetyl-2-O-benzoyl-3,4-di-O-benzyl-alpha-D-mannopyranosyl trichloroacetimidate as the key glycosyl donor in an 'inverse Schmidt' procedure.
The first synthesis of the macrolide insecticide A83543A (lepicidin A) has been completed using a Diels-Alder strategy to construct the carbocyclic framework. Diene synthesis through Pd-catalyzed Stille coupling of a macrocyclic vinylstannane and suitably functionalized vinyl iodide was followed by a diastereoselective Lewis acid-mediated intramolecular Diels-Alder reaction to construct the trans hydrindene
Abstract The reaction of partially protected aldoses with (carbomethoxymethyl)triphenylarsonium bromide and zinc in toluene gave E α,β-unsaturated acyclic esters. When intramolecular transest erification occurred, bicyclic 1,4-lactone derivatives were formed concurrently. Otherwise, using these non alcaline conditions, olefination did not favour the formation of C -glycosyl derivatives. On the other
Synthesis of glyco-1-ynitols via 1,1-dibromo-1-alkenes from partially and unprotected aldoses
作者:Franck Dolhem、Catherine Lièvre、Gilles Demailly
DOI:10.1016/s0040-4020(02)01486-2
日期:2003.1
We report the synthesis of 1,1-dibromo-1-alkenes from partially and unprotected aldoses and the synthesis of glyco-1-ynitols from these dibromocompounds. The 1,1-dibromo-1-alkenes were obtained by the reaction of dibromomethyl-triphenylphosphonium bromide in the presence of zinc in refluxing 1,4-dioxane. As an example, when the reaction is performed on 2-deoxy-5-O-trityl-d-ribofuranose (1) the corresponding