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以D-木糖、L-岩藻糖和D-甘露糖为起始原料,分别合成4-羟基木糖受体、岩藻糖乙基硫苷供体以及D-鼠李糖三氯乙酰亚胺酯供体,而后通过[2+1]偶联策略,得到结构为α-D-鼠李糖-(1→3)-α-L-岩藻糖-(1→4)-β-D-木糖的三糖对甲氧基苯基糖苷,该三糖为固氮螺菌(Azospirillum brasilense type strain Sp7)表面脂多糖的重复单元结构.在关键的α-D-鼠李糖供体与双糖受体糖苷化反应中,通过低温条件下双糖受体中岩藻糖3、4位两个羟基的选择性糖苷化反应,实现区域、立体选择性构建全保护的三糖.该合成路线步骤简洁,以L-岩藻糖为原料计算,目标三糖总收率达到10%,适宜于目标产物的大量制备.初步植物生长调节活性研究表明,采用砂培发芽床的生物测定试验表明在100 mg/L浓度下,所合成的目标三糖浸种处理能促进10℃低温条件下玉米种子的出苗和幼苗生长,对出苗率、株高和叶面积分别提高11.0%、13.1%和87.8%,初步判断该三糖具有一定的植物生长调节活性.
D-xylose, L-fucose and D-mannose were used as starting materials to synthesize 4-hydroxy xylose receptor, fucosyl ethyl thioglycans donor and D-rhamnose trichloroacetyl (1 → 3) -α-L-fucose- (1 → 4) -β-D with the structure of α-D-rhamnose- - xylose trisaccharide p-methoxyphenylglycoside, which is a repeating unit structure of lipopolysaccharide on the surface of Azospirillum brasilense type strain Sp7 In the presence of a key α-D-rhamnose donor and bis In glycosylation of sugar receptor, the fully protected trisaccharide can be selectively constructed in a regioselective manner through the selective glycosylation reaction of two hydroxyl groups at the 3,4 position of fucose in the disaccharide acceptor under the condition of low temperature. The steps are simple, L-fucose as the raw material, the total target trisaccharide yield of 10%, suitable for the preparation of the target product in large quantities.Studies on preliminary plant growth regulatory activity, using sand culture seed germination bed bioassay showed that in the Under the concentration of 100 mg / L, the soaking of the target trisaccharide could promote the seedling emergence and seedling growth of maize seedlings under the low temperature of 10 ℃, and increase the emergence rate, plant height and leaf area by 1 1.0%, 13.1% and 87.8% respectively. It was preliminarily determined that the trisaccharide had some plant growth regulatory activities.