Cycloascauloside b from <Emphasis Type="Italic">Astragalus caucasicus</Emphasis>

The structure of a new cycloartane glycoside isolated from leaves of Astragalus caucasicus Pall. (Leguminosae) was elucidated using chemical transformations and spectral data. Cycloascauloside B is 20R, 25-epoxy-24S-cycloartan-3β,6α,16β,24-tetraol 3-O-[α-L-rhamnopyranosyl-(1å2)]-β-D-glucopyranoside.     

CDn体系DEPT谱线的理论研究

本文根据算符函数的幂级数展开,给出了描述高自旋弱耦合体系的积算符理论,并用来描述I_n S((1)/2)体系(其中I=1/2,1,…)的DEPT实验.给出I(1)_n S((1)/2)体系(例如CD_n)DEPT谱线的增益系数的普遍公式,并提出了用作图法得出谱线结构的方法.     

一种新的DENUDATINE型C20二萜生物碱结构的NMR研究

从内蒙西伯利亚乌头中分离得一个新的C20二萜生物碱,采用选择性远程DEPT,同核和异核二维NMR技术相结合进行了研究,其结构确定为Lepenine的C－11基向立体异构体,定名为11a－hydroxylapenine．结果表明,选择性远程DEPTNMR技术对于连接这类化合物中被季碳和杂原子分割的NMR自旋体系,测定基本骨架和确定信号归属都有独到之处．     

一种新的DENUDATINE型C20二萜生物碱结构的NMR研究

从内蒙西伯利亚乌头中分离得一个新的C₂₀二萜生物碱,采用选择性远程DEPT,同核和异核二维NMR技术相结合进行了研究,其结构确定为Lepenine的C-11基向立体异构体,定名为11a-hydroxylapenine.结果表明,选择性远程DEPTNMR技术对于连接这类化合物中被季碳和杂原子分割的NMR自旋体系,测定基本骨架和确定信号归属都有独到之处.     

Triterpene glycosides from <Emphasis Type="Italic">Astragalus</Emphasis> and their genins. LXXX. Cyclomacroside D,a new bisdesmoside

The structure of the new cycloartane glycoside cyclomacroside D, which was isolated from Astragalus macropus Bunge (Leguminosae) and is 24R-cycloartan-1α,3β,7β,24,25-pentaol 3-O-α-L-rhamnopyranoside–24-O-β-D-xylopyranoside, was proved. Presented at the 7th International Symposium on the Chemistry of Natural Compounds (SCNC, Tashkent, Uzbekistan, October 16–18, 2007). Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 48–50, January–February, 2009.     

乙基紫苏霉素硫酸盐的选择性远程DEPT和二维NMR研究

本文通过选择性远程DEPT和二维NMR实验研究了由紫苏霉素合成的乙基紫苏霉素硫酸盐的¹H和¹³C NMR谱,推定其结构为(1),并且对其NMR谱峰归属作了确定。     

南海海绵Dysidea fragilis中两个倍半萜内酯的NMR研究

用一维¹H、¹³C NMR谱、DEPT ¹³C NMR谱、选择性远程DEPT ¹³C NMR、¹H-¹H COSY和¹³C-¹H COSY二维核磁共振技术研究了南海海绵Dysidea fragilis中的两个倍半萜herbadysidolide(1)和furodysinin lactone(2),确认了化学结构,并对其¹³C NMR和¹H NMR谱进行了归属.药理活性试验表明:1和2具有一定的心血管活性.     

一维多重接力COSY和选择性远程DEPT核磁共振技术在新分子骨架生物碱结构测定和谱峰归属研究中的应用

自防已科千金藤根中分得一个新型分子骨架的四氢异喹林类生物碱—excentricine(1)。本工作采用一维多重接力COSY和选择性远程DEPT核磁共振新技术成功地确定谱峰归属,鉴别和连结被季碳和杂原子分割开的自旋体系,测定了其结构。     

Acetone‐induced polymerisation of 3‐aminopropyltrimethoxysilane (APTMS) as revealed by NMR spectroscopy

We followed the reactivity of acetone with 3‐aminopropyltrimethoxysilane, a potential organosilane coupling agent, by ¹H, ¹³C and ²⁹Si NMR spectroscopy. Selective 1D and 2D‐edited NMR experiments significantly contributed to simplify the spectral complexity of reaction solution and elucidated molecular structures within progressive reaction phases. The course of the 3‐aminopropyltrimethoxysilane reaction with acetone was shown by a progressive decrease of both reactants, and a concomitant appearance of water and methanol, due to formation of imine and hydrolysis of alkoxysilane groups, respectively. The occurrence of multiple siloxane linkages in a progressively larger cross‐linked macromolecular structure was revealed by DOSY‐NMR experiments and new signals in ²⁹Si‐NMR spectra at different reaction times. The NMR approach described here may be applied to investigate the reactivity of other γ‐aminopropylalkoxysilanes and contribute to define procedures for the preparation of silica‐based materials. Copyright © 2014 John Wiley & Sons, Ltd.     

Triterpene glycosides from <Emphasis Type="Italic">Astragalus</Emphasis> and their genins. LXXXI. Chemical transformation of cycloartanes. VII. Synthesis of cyclosiversigenin lactone

The lactone 20R-25-norcycloartan-3β,6α,16β-triol-20,24-olide was synthesized from cyclosiversigenin. Presented at the 1st International Symposium on Edible Plant Resources and the Bioactive Ingredients, Xinjiang, China, July 25–27, 2008. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 324–327, May–June, 2009.