Crystal structure of the cytotoxic marine alkaloid 2-bromoleptoclinidinone

2-Bromoleptoclinidinone methanol solvate, C₁₈H₈BrN₃O·CH₄O, crystallizes in the orthorhombic space group Pbca with a = 15.7013(2), b = 7.3308(1), and c = 26.9326(1) Å. The molecule is essentially planar, with the largest deviations occurring at bromine (–0.21 Å), carbonyl oxygen O(l) (+0.19 Å) and in ring-A (C(9) –0.15 Å, C(10) –0.15 Å). Methanol occupies the 1,10-phenanthroline-like metal binding site of the title compound.     

Concise and divergent total synthesis of swainsonine, 7-alkyl swainsonines, and 2,8a-diepilentiginosine via a chiral heterocyclic enaminoester intermediate

The concise and divergent total syntheses of (−)-swainsonine, (−)-7-alkyl swainsonines, and (−)-2,8a-diepilentiginosine from a common chiral heterocyclic enaminoester intermediate in five-step sequences are presented. The highly efficient annulation reaction of the chiral heterocyclic enaminoester with various α,β-unsaturated carboxylates, and a straightforward carboxy inversion constituted the key features of the synthetic pathway. This work provides an example for divergent synthesis of different natural and unnatural polyhydroxylated indolizidines from a readily available platform.     

A novel approach to the taxane ABC ring system through chemical conversion from C19-diterpenoid alkaloid deltaline

A novel approach to the highly functionalized taxane ABC ring system through chemical conversion of the C₁₉-diterpenoid alkaloid deltaline (1) was achieved in six steps (1→17) in 18% overall yield mainly by Grob fragmentation, fission of the Δ⁹⁽¹⁴⁾ double bond, followed by aldol condensation, and Pelletier's cleavage process.     

Vilmoraconitine, a novel skeleton C19-diterpenoid alkaloid from Aconitum vilmorinianum

A novel C₁₉-diterpenoid alkaloid vilmoraconitine (1) was isolated from the roots of Aconitun vilmorinianum. Its structure was mainly determined by MS, 2D NMR, and X-ray methods. This is the first aconitine-type C₁₉-diterpenoid alkaloid with one three-membered ring at C-8, C-9, and C-10.     

石松碱的合成方法综述

石松碱是第一个被发现的石松生物碱类化合物, 其较好的生物活性引起了合成工作者的兴趣. 较全面地介绍了石松碱的各种合成路线, 并对其做了简单分析.     

3,6-二氯哒嗪-金鸡纳生物碱衍生物催化不对称“中断的”Feist-Bénary反应的研究

将3,6-二氯哒嗪-金鸡纳生物碱衍生物用于催化β-二羰基化合物与溴乙酰甲酸乙酯/β-取代的溴乙酰甲酸乙酯的不对称“中断的”Feist-Bénary反应, 得到了较高的化学产率(72%～97%)和最高达93% ee的立体选择性.     

片螺素D (LMD)及其衍生物的研究进展

片螺素(Lamellarins)是一类从前腮亚纲软体动物中分离的具有较强生物活性的海洋吡咯生物碱, 迄今已发现40余种. 片螺素D (LMD)是片螺素系列化合物中生物活性最强的, 是继喜树碱(CPT)之后的一种新的拓扑异构酶1抑制剂, 对一系列癌细胞具有很强的细胞毒性, 并作用于细胞线粒体, 影响细胞周期, 诱导细胞凋亡. 结合作者的研究工作, 综述了LMD及其衍生物的最新研究进展, 重点介绍其化学合成(包括合成中心吡咯环和以吡咯环为中心的两大类合成方法), 并展望了该领域今后的发展趋势.     

Microcalorimetric investigation of the effect of berberine alkaloids from <Emphasis Type="Italic">Coptis chinensis</Emphasis> Franch on <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> growth

The inhibitory effects of three berberine alkaloids (BAs) from rhizome of Coptis chinensis Franch, a traditional Chinese medicinal (TCM) herb, on Staphylococcus aureus growth were investigated by microcalorimetry. The power-time curves of S. aureus with and without BAs were acquired; meanwhile the extent and duration of inhibitory effects on the metabolism were evaluated by studying the growth rate constant (k), half inhibitory ratio (IC₅₀), maximum heat-output power (P _max), peak time of maximum heat-output power (t _p) and total heat production (Q _t). The value of k of S. aureus in the presence of the three BAs decreased with the increasing concentrations of BAs. Moreover, P _max was reduced and the value of t _p increased with increasing concentrations of the three drugs. The inhibitory activity varied with different drugs. The values of IC₅₀ of the three BAs are respectively, 101.4 μg/mL for berberine, 241.0 μg/mL for palmatine and 792.3 μg/mL for jateorrhizine. The sequence of antimicrobial activity of the three BAs is: berberine > palmatine > jateorrhizine. It is suggested that the functional group methylenedioxy or methoxyl at C2 on the phenyl ring could possibly improve antimicrobial activity more strongly than hydroxyl at C2 on the phenyl ring. Supported by the National Natural Science Foundation of China (Grant No. 30625042)     

An enzyme-linked immunosorbent assay for aconitine-type alkaloids using an anti-aconitine monoclonal antibody

3-Succinylaconitine was conjugated with bovine serum albumin (BSA) for use as an immunogen for the preparation of a monoclonal antibody (MAb) against aconitine (Aco). Splenocytes from mice immunized with the Aco-BSA conjugate were fused with an aminopterin-sensitive mouse myeloma cell line, P3-X63-Ag8-653, and a hybridoma secreting a MAb against Aco was successfully obtained. The MAb cross-reacted with mesaconitine, hypaconitine and jesaconitine, which are Aco-type alkaloids, but not with any other compounds examined. The full measurement range of an enzyme-linked immunosorbent assay (ELISA) developed using the new MAb extended from 100 ng mL⁻¹ to 1.5 μg mL⁻¹ of Aco. The concentrations of Aco-type alkaloids in various Aconiti radixes assayed using the new ELISA method showed good agreement with previous reports.     

New C20-diterpenoid alkaloids from Aconitum sinomontanum

Two new denudatine-type C₂₀-diterpenoid alkaloids, named sinomontanidines A (1) and B (2), were isolated from the roots of Aconitum sinomontanum Nakai. Their structures were elucidated by extensive analysis of 1D, 2D NMR, and MS data.