低压催化氚化亮石松碱的定位效应的研究

A STUDY ON THE LOCATION TRITIUM—LABELLNG OF SELAGING BY LOW PRESSURE CATALYTIC METHOD.

近年来,中草药有效成分的研究引起国内外有关学者普遍关注。氚标记中草药有效成分是研究其相应的药代动力学和代谢产物的主要手段,它具有操作简便,条件温和等优点,但是一般氚化方法均不能明确给出氚化位置。而研究氚化定位效应又是药理工作者急待解决的重要课题,所以在很大程度上限制了该项技术的使用范围。最近,郑冬珠等人用FX—100型核磁共振谱仪给出了在PdO催化剂存在条件下,低压氚化亮石松碱的氚化位置及其相对含量。本文在前文基础上,以亮石松碱为底物,根据Fraser和Garnett等人提出的氢—氚同位素交换反应动力学理论,采用CNDO/2法,对PdO催化亮石松碱的立体构型讲行了计算,得出一些有意义的结果。

In this article, the location tritium---labelling of the selaging by low pressure method in Pdo catalyst has been investigated using CNDO/2 method. The result show that the decay---induced labelling contributes less to the total yield at high concen-trations of tritium, since the ion molecule ~3HeT^+ fomed fromβ^- decay of tritium has a G(T) value. The large amount of tritiumβ--deeay energy dissipated in the gas phase. But in the case of labelling by low pressure method, the species are electron,tritium atom, and other reactive species. The cslculated results were good agree with the experimental Aalue wich was confirmed by NMR method. It seems that calculation of superdelocalizabitity Sr^(R) using CNDO/2 method may be used as a useful tool for the location of tritium labelling on Chinese medical herbs.