A new diterpenoid alkaloid from Aconitum hemsleyanum

Abstract

A new C₁₉-diterpenoid alkaloid named hemsleyaline (1), along with fourteen known alkaloids (2-15), were isolated from the roots of Aconitum hemsleyanum Pritz. (Ranunculaceae), a herbal medicine in southwest China. Their structures were established on the basis of extensive spectroscopic analyses. Compound 1 showed mild cholinesterase inhibitory effect with IC₅₀ value of 471?±?9?μM.     

Four new compounds from Neoboletus magnificus

Abstract

Four new compounds, compounds 1, 2, 4, 6, along with two known compounds 3, 5, were isolated from the methanol extract of the fruiting body of Neoboletus magnificus. The structures of compounds were elucidated by HRMS and NMR spectroscopic methods. The in vitro anti-inflammatory activity of the isolated compounds was evaluated.     

Iboga Inspired N-Indolylethyl-Substituted Isoquinuclidines as a Bioactive Scaffold: Chemoenzymatic Synthesis and Characterization as GDNF Releasers and Antitrypanosoma Agents

The first stage of the drug discovery process involves the identification of small compounds with biological activity. Iboga alkaloids are monoterpene indole alkaloids (MIAs) containing a fused isoquinuclidine-tetrahydroazepine ring. Both the natural products and the iboga-inspired synthetic analogs have shown a wide variety of biological activities. Herein, we describe the chemoenzymatic preparation of a small library of novel N-indolylethyl-substituted isoquinuclidines as iboga-inspired compounds, using toluene as a starting material and an imine Diels–Alder reaction as the key step in the synthesis. The new iboga series was investigated for its potential to promote the release of glial cell line-derived neurotrophic factor (GDNF) by C6 glioma cells, and to inhibit the growth of infective trypanosomes. GDNF is a neurotrophic factor widely recognized by its crucial role in development, survival, maintenance, and protection of dopaminergic neuronal circuitries affected in several neurological and psychiatric pathologies. Four compounds of the series showed promising activity as GDNF releasers, and a leading structure (compound 11) was identified for further studies. The same four compounds impaired the growth of bloodstream Trypanosoma brucei brucei (EC₅₀ 1–8 μM) and two of them (compounds 6 and 14) showed a good selectivity index.     

实时直接分析-串联质谱法快速筛查火锅底料、牛肉面汤及调味料中罂粟壳生物碱

建立了采用实时直接分析-串联质谱(DART-MS/MS)对火锅底料、牛肉面汤及调味料中5种非法添加的罂粟壳生物碱进行快速筛查的方法。样品经乙腈提取净化后,在离子化温度为300℃、栅极电压为150 V、进样速率为0.8 m m/s的DART离子源正离子模式条件下进样,以电喷雾离子源正离子多反应监测(MRM)模式进行检测,实现了样品经简单预处理后使用DART-MS/MS进行检测的新方法。该方法简便、快速,能满足大批量非法添加样品的快速筛查分析要求。     

金鸡纳碱衍生物修饰的负载铱催化剂催化芳香酮不对称加氢

以金鸡纳碱衍生物作为手性修饰剂, 研究了三苯基膦稳定的Ir/SiO₂催化剂催化芳香酮多相不对称加氢. 通过电感耦合等离子体原子发射发谱(ICP-AES)、高分辨透射电镜(HRTEM)、X 射线光电子能谱(XPS)、Brunauer-Emmett-Teller (BET)比表面积测试等固体表面分析手段对负载铱催化体系进行了表征; 利用红外(IR)光谱、固体核磁共振(NMR)等分析手段初步表征了负载铱多相催化体系中手性修饰剂-金属-稳定剂在载体上的相互作用; 利用“均相与多相催化体系的对比”、“催化剂稳定性实验”、“汞中毒实验”等方法阐明了手性修饰的负载铱催化体系是多相催化体系. 还考察了稳定剂种类、修饰剂种类、金属负载量、溶剂、碱添加剂种类等因素对不对称加氢反应的影响. 结果表明, 金鸡纳碱衍生物对Ir/SiO₂催化剂具有较好的修饰作用, 在优化反应条件下苯乙酮及其衍生物加氢反应的对映选择性为52%-96%, 4-乙酰基吡啶、2-乙酰基噻吩及2-乙酰基呋喃加氢反应的对映选择性可分别达到74%、75%及63%.     

海绵Phacelliafusca中含氮化合物的分离与结构鉴定

从采自中国南海西沙群岛海域的海绵Phacellia fusca Schmidt中得到4个含氮 化合物。经~1H NMR,~(13)C NMR,HMQC,HMBC,~1H-~1HCOSY,FABMS和EIMS等光谱分析 ，确证其结构分别为：N,N'-二[2-乙氧基-1（Z）-乙烯基]脲（1），2- Bromoaldisin(2),Aldisin(3)Dibromophakellin盐酸盐(4)。其中化合物1为一具有 对称结构的新脲类化合物，命名Phacelliaurea A；化合物4是首次从该海绵中分离 得到的已知胍基生物碱，首次报到了它的~(13)C NMR数据及其归属。     

A new Dendrobine-Type Alkaloid from Dendrobium nobile

A new dendrobine-type alkaloid has been isolated from stems of Dendrobium nobile lindl.Its structure has been identified on the basis of spectroscopic method.     

From building block to natural products: a short synthesis and complete NMR spectroscopic characterization of (±)-anatabine and (±)-anabasine

A short and straightforward synthesis of the racemic tobacco alkaloids anatabine and anabasine in five and six steps, respectively, from 3-pyridinecarboxaldehyde utilizing Barbier-type Zn-mediated allylation and ring-closing olefin metathesis, as the key steps, is reported. Additionally, a complete NMR spectroscopic analysis of the final products is carried out and full assignment of the NMR spectra of anatabine and anabasine with accurate coupling constants is accomplished and reported here for the first time.     

Alkaloids from the Roots of Saccopetalum prolificum

In recent years, an increased interest in the phytochemistry of the Annonaceae has beensparked by the isolation of the antileukemic Annonaceous acetogenin'. Saccopela/umprolificllm (Chun el How) Tsiang (Allnonaceae) is an evergreen tree distributed inHainan Province, P. R. China. The ethanolic extract of the plant exhibited cell growthinhibitory activity (20 ig/ml) against LIZ10 lymphocytic leukemia. A new alkaloid,prolifine (l), was isolated from the roots of S. proldicum, in addition t…     

Asymmetric total synthesis of the indole alkaloid cyclopiazonic acid and first structure-activity data

The indole alkaloid α-cyclopiazonic acid (CPA) is one of the few known inhibitors of sarco(endo)plasmic reticulum Ca²⁺-ATPase (SERCA) besides the terpenoids thapsigargin and artemisinin. We report here the first asymmetric total synthesis of cyclopiazonic acid by a modification of the Knight synthesis, currently the most efficient route to CPA. First structure-activity data of CPA derivatives and stereoisomers are presented and will be discussed in connection with the published crystal structures of CPA-SERCA complexes.