贝塔-D-曼南的直接化学合成:贝塔-(1-->2) 和贝塔-(1-->4) 系列
David Crich1, Abhisek Banerjee, Qingjia Yao
1Department of Chemistry, University of Illinois, 845 West Taylor Street, Chicago, IL 60607-7061, USA.
Journal of the American Chemical Society
|November 13, 2004
概括
贝塔曼南的直接合成揭示了不同的结构性质. β-(1-->4) - - 曼南表现出有序结构和高产量,而β-(1-->2) - - 曼南表现出无序结构和较低产量,这是由于硬质阻碍.
科学领域:
- 碳水化合物化学 碳水化合物化学
- 葡萄糖科学 (Glycoscience) 是一种科学.
- 聚合物化学 聚合物化学
背景情况:
- 氧化糖合成对于了解碳水化合物的结构和功能至关重要.
- 贝塔曼南是重要的多糖类,具有不同的生物作用.
- 在甘氨基化中控制立体选择性和产量是一个关键的挑战.
研究的目的:
- 报告beta-(1-->2) -manooctaose和beta-(1-->4) -mannohexaose的直接合成情况.
- 研究链接类型对合成效率和聚合物结构的影响.
- 为了比较合成的β-(1-->2)-和β-(1-->4)-曼的结构和物理特性.
主要方法:
- 使用4,6-O-基烯保护的β-曼诺西尔供体进行合成.
- 采用硫氧化物合协议进行β-(1-->2)-曼合成.
- 适用于β-(1-->4) - - 曼南合成的基化物/硫胺方法.
主要成果:
- β-(1-->4) - 曼南合成显示一致的高产量和立体选择性随着链条长度的增加.
- β-(1-->2) -曼南合成表现出降低的产量和对四糖和更高糖的选择性.
- 通过NMR光谱和物理特性 (与高融固体) 证实了结构差异.
结论:
- β-(1-->4)-曼南的合成效率更高,产生了一个有序的聚合物.
- β-(1-->2)-曼南的合成效率较低,产生一种因硬质因子而导致的无序聚合物.
- 结构顺序对β-曼南的物理性质和合成可访问性产生重大影响.
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