野油菜黄单胞菌海棠致病变种GSPB 525脂多糖O链多糖重复单元木糖基化鼠李糖五糖的合成。

Synthesis of an xylosylated rhamnose pentasaccharide, the repeating unit of the O-chain polysaccharide of the lipopolysaccharide of Xanthomonas campestris pv. begoniae GSPB 525.

作者信息

Zhang Jianjun, Kong Fanzuo

机构信息

Research Center for Eco-Environmental Sciences, Academia Sinica, PO Box 2871, 100085, Beijing, PR China.

出版信息

Carbohydr Res. 2002 Mar 1;337(5):391-6. doi: 10.1016/s0008-6215(01)00330-5.

DOI:10.1016/s0008-6215(01)00330-5

PMID:11861012

Abstract

A xylosylated rhamnose pentasaccharide, alpha-L-Rhap-(1-->3)-[beta-L-Xylp-(1-->2)-]-alpha-L-Rhap-(1-->3)-[beta-L-Xylp-(1-->4)]-L-Rhap, the repeating unit of the O-chain polysaccharide (OPS) of the lipopolysaccharides of Xanthomonas campestris pv. begoniae GSPB 525 was synthesized by a highly regio- and stereoselective way. Thus coupling of 1,2-O-ethylidene-beta-L-rhamnopyranose (1) with 2,3,4-tri-O-benzoyl-alpha-L-rhamnopyranosyl trichloroacetimidate (2) to give (1-->3)-linked disaccharide (3), subsequent benzoylation, deethylidenation, acetylation, 1-O-deacetylation, and trichloroacetimidation afforded the disaccharide donor 11. Condensation of 11 with 1 yielded 2,3,4-tri-O-benzoyl-alpha-L-rhamnopyranosyl-(1-->3)-2-O-acetyl-4-O-benzoyl-alpha-L-rhamnopyranosyl-(1-->3)-1,2-O-ethylidene-beta-L-rhamnopyranose (12), and selective deacetylation of 12 yielded the trisaccharide diol acceptor 15. Coupling of 15 with 2,3,4-tri-O-benzoyl-alpha-L-xylopyranosyl trichloroacetimidate (16), followed by deprotection, gave the target pentasaccharide 19.

摘要

一种木糖基化的鼠李糖五糖，α-L-鼠李糖基-(1→3)-[β-L-木糖基-(1→2)-]-α-L-鼠李糖基-(1→3)-[β-L-木糖基-(1→4)]-L-鼠李糖，是野油菜黄单胞菌致病变种秋海棠致病变种GSPB 525脂多糖O链多糖（OPS）的重复单元，通过高度区域和立体选择性方法合成。因此，1,2-O-亚乙基-β-L-鼠李吡喃糖（1）与2,3,4-三-O-苯甲酰基-α-L-鼠李吡喃糖基三氯乙酰亚胺酯（2）偶联得到（1→3）连接的二糖（3），随后进行苯甲酰化、脱亚乙基化、乙酰化、1-O-脱乙酰化和三氯乙酰亚胺化，得到二糖供体11。11与1缩合得到2,3,4-三-O-苯甲酰基-α-L-鼠李吡喃糖基-(1→3)-2-O-乙酰基-4-O-苯甲酰基-α-L-鼠李吡喃糖基-(1→3)-1,2-O-亚乙基-β-L-鼠李吡喃糖（(12），12的选择性脱乙酰化得到三糖二醇受体15。15与2,3,4-三-O-苯甲酰基-α-L-木糖吡喃糖基三氯乙酰亚胺酯（16）偶联，随后脱保护，得到目标五糖19。