School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Quai Ernest-Ansermet 30, CH-1211 Geneva 4, Switzerland.
Molecules. 2011 Aug 25;16(9):7199-209. doi: 10.3390/molecules16097199.
The strict application of IUPAC rules for the numbering of tropane alkaloids is not always applied by authors and there is hence a lot of confusion in the literature. In most cases, the notation of 3, 6/7-disubstituted derivatives has been chosen arbitrarily, based on NMR and MS data, without taking into account the absolute configuration of these two carbons. This paper discusses the problem and the relevance of CD and NMR to determine molecular configurations. We report on the use of (1)H-NMR anisochrony (Δδ) induced by the Mosher's chiral auxiliary reagents (R)-(-)- and (S)-(+)-α-methoxy-α-trifluoromethyl-phenylacetyl chlorides (MTPA-Cl), to determine the absolute configuration of (3R,6R)-3α-hydroxy-6β-senecioyloxytropane, a disubstituted tropane alkaloid isolated from the aerial parts of Schizanthus grahamii (Solanaceae). These analytical tools should help future works in correctly assigning the configuration of additional 3, 6/7 disubstituted tropane derivatives.
IUPAC 关于托烷生物碱编号的规则的严格应用并不总是被作者所采用，因此在文献中存在很多混淆。在大多数情况下，基于 NMR 和 MS 数据，3、6/7-二取代衍生物的标记是任意选择的，而没有考虑这两个碳原子的绝对构型。本文讨论了这个问题以及 CD 和 NMR 对确定分子构型的相关性。我们报告了使用（1）H-NMR 各向异性（Δδ）来确定（3R，6R）-3α-羟基-6β-千里光酰氧基托烷的绝对构型，（3R，6R）-3α-羟基-6β-千里光酰氧基托烷是从茄科山梗菜属植物 Schizanthus grahamii 的地上部分分离得到的一种二取代托烷生物碱。这些分析工具应该有助于未来正确分配其他 3、6/7-二取代托烷衍生物的构型。
