甙中寡糖链结构测定的核磁共振研究

NMR study on the structure determination of oligosaccharide chainsof the saponin

目的：直接测定甙类药物中寡糖链的结构。方法：新建立的一维ＳＥＭＤＹ，旋转坐标系ＮＯＥ差谱和选择性远程ＤＥＰＴ核磁共振技术相互配合。结果和结论：采用一维ＳＥＭＤＹ技术可以从高度重叠的１Ｈ－ＮＭＲ谱中得到糖体的吸收形亚谱，为利用ＮＯＥ与核间距关系确定糖体之间和糖体与甙元之间的连接方式创造了条件。采用旋转坐标系ＮＯＥ差谱技术测定不受分子相关时间的影响，并且可以从高度重叠的１Ｈ－ＮＭＲ谱中定量测定ＮＯＥ增益。采用选择性远程ＤＥＰＴ技术可以在短时间内得到远程１３Ｃ－１Ｈ偶合信息。本方法的优点在于不需要对化合物进行化学降解或衍生化，能够直接测定糖的连接顺序和连接位置，结果可靠。

Objective: To directly determine the chemical structure of oligosaccharide chains of the saponin. Methods: 1DSEMDY, NOE difference spectroscopy in rotating frame and selective longrange DEPT techniques were used. Results and Conclusion: The sites of glycosylation and the sequence of sugars in the glycoside could be determined unambiguously and total assignment of severely overlapping proton resonance of sugar residues was achieved by combined use of the 1DSEMDY, NOE difference spectroscopy in rotating frame and selective longrange DEPT techniques, without the need for recourse to chemical degradation or modification.