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几种具有生物活性糖缀合物的全合成

Total Synthesis of Some Active Glycoconjugates

【作者】 孙建松

【导师】 韩秀文; 俞飚;

【作者基本信息】 中国科学院研究生院(大连化学物理研究所) , 有机化学, 2005, 博士

【摘要】 皂甙和糖脂是自然界广泛存在的糖缀合物,他们是许多药用植物的有效成分,具有多种生物活性。本论文完成了几个有生物活性、结构独特的皂甙和糖脂的合成,对类似物的合成有借鉴意义,同时为测试其生物活性、研究构效关系奠定了基础。氨基葡萄糖皂甙是一类重要的皂甙,虽然发现的数目不多,但均具有较好的生物活性,特别是具有抗癌活性。到目前为止,还没有发现关于氨基葡萄糖皂甙合成的报道。本论文利用三氟乙酰亚胺酯给体,采取线性逐步合成的策略完成了氨基葡萄糖皂甙的全合成。由于氨基葡萄糖皂甙结构变化具有规律性,因此论文中目标分子的合成将会对其它氨基葡萄糖皂甙的合成具有借鉴意义。Caminoside A是从海绵中分离出的新的四糖糖脂抗生素,研究发现,它是第三类分泌系统(TTSS)的第一个抑制剂。本论文以葡萄糖、半乳糖及L鼠李糖为初始原料,经57步反应完成了Caminoside A的全合成。在合成过程中利用氧化还原反应立体选择性地构建了1,2顺式糖苷键。同时揭示了“匹配”“不匹配”原理在寡糖合成中的重要性,研究结果对预测糖苷化反应具有一定的指导意义。Anemoclemoside B是一类结构独特的分子,在这类分子中存在着环状缩醛糖苷键,到目前为止没有有关合成的报道。利用我们自己发展的构建链状糖苷键的方法,方便高效地合成了目标分子。在合成过程中,利用苄基保护28位羧基,在脱除过程中并没用影响到甙元中的双键,并且可以和糖链上的苄基保护基一并脱除,这样就简化了保护基操作,提高了合成效率。目标分子的高效合成为研究该分子的生物活性及其构效关系奠定了基础。

【Abstract】 Steroidal glycosides widely occur as natural products. They act as active compounds of many medical plants and exhibit various bioactivities. In this thesis three molecules of steroidal glycosides and glycolipid which either have good bioactivities or have unique structure were synthesized. The methods and strategies used in this thesis can be used again in the synthesis of these types of molecules and the synthesis can serves as a basis for testing their bioactivities, revealing the relationships between structure and bioactivity.Saponins containing N-acetylglucosamine are very important saponins. Though N-acetylglucosamine containing saponins are rare, they all have good bioactivities, especially anticancer activities. So far no paper was published about the synthesis of this type of saponins. Employing glycosyl trifluroacetimidates and thioglycoside, we finished the synthesis of the target molecule in a stepwise fashion. Because the structures of this type of saponins are highly conservative, the synthesis of target molecule can be regardde as reference to the synthesis of N-acetylglucosamine containing saponins.Caminoside A, a novel antimicrobial tetrasaccharide glycolipid from marine sponge, which represents the first bacterial type III secretion system inhibitor (TTSS), is synthesized in a total of 57 steps starting from D-glucose, D-galactose, L-rhamnose, and 9-decenal. In the synthesis of Caminoside A, construction of the 1,2-cis-β-manopyranoside-type linkage of the 6-deoxy-talose is achieved by oxidation-reduction sequence. From the results which are get from my experiments and from references, we draw some primary conclusion about

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