A new lactam alkaloid from Portulaca oleracea L. and its cytotoxity

A new lactam alkaloid named oleraciamide D (1), indentified as (5R)-4-(3-methoxy-4-hydroxyphenyl)-5-(4-hydroxyphenyl)-5,6-dihydropyridin-2(1H)-one, together with five known compounds, indole-3-aldehyde (2), portulacatone (3), N-trans-feruloyloctopamine (4), N-trans-feruloyl-3′-O-methyldopamine (5) and N-trans-feruloyltyramine (6) were isolated from Potulaca oleracea L. Among them, indole-3-aldehyde (2) was isolated from the medicine for the first time. The structure of the new alkaloid was elucidated via UHPLC-ESI-Q-TOF/MS, 1D NMR and 2D NMR. The five known compounds were established by comparing the ¹H-NMR and ¹³C NMR with the reported literature. Oleraciamide D (1) showed cytotoxicity against SH-SY5Y cells when concentration at 50 uM by CCK-8 method.     

Coumarins and alkaloids from the roots of Toddalia asiatica

The EtOAc and MeOH extracts of the roots of Toddalia asiatica Lam. were investigated for the roots’ chemical constituents. Two new compounds including 2′R-acetoxytoddanol (1) and 8S-10-O-demethylbocconoline (3) as well as 15 known compounds were isolated. Compound 10 showed strong cytotoxicity against KB cells with an IC₅₀ value of 2.60 μg/mL, which is nearly equal to the ellipticine standard, but showed no activity against Vero cells. Alkaloid 3 displayed weak cytotoxicity against the KB cell line with an IC₅₀ value of 21.69 μg/mL.     

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.     

Unusual nucleotide stability through C–H ⋅ ⋅ ⋅ water interaction in crystal: Recognition of nucleotide-water duplex-helix

The direct and indirect roles of the C2- and C8-bonded water molecules (C–H    O_W) in the stabilization of unusual inosine monophosphate containing nucleotides have been observed in their highly hydrated and amino acid cocrystals, which have been discussed in this work for the first time. The intermolecular H-bonding of W_R (the oxygen of ribose 2- and 3-hydroxyls bonded water molecule, O2    W_R    O3) with the C2–H bonded O_W's (O_W    W_R 2.43–2.78 Å) can influence the ribose and thus the nucleotide stability, whereas the water molecule (O_W) of C8–H    O_W can participate in the base stability by sandwiching the stacked purines through N7    O_W    N7 intermolecular interactions, with N7    O_W 2.63–2.75 Å. However, in some cases the water oxygen (O_W) of C8–H can get intermolecularly H-bonded to water molecular oxygen W_N (with O_W    W_N 2.57–2.85 Å), which has previously stabilized the nucleotide single-strand through intermolecular stacking N7    W_N    N7 interaction (N7    W_N 2.56–2.63 Å). The conjugal survival of the H-bonded nucleotide single-strand with the water-helix thus forming the duplex and its stabilization through the C–H    O_W mediated water molecular (O_W) cooperative H-bonding network, specially with the ribose and the base units, in the crystals could favor the support of single-stranding potentiality and thus the stability of the purine-rich RNAs or the small unusual nucleotides in the aquated environment besides the other interactive factors.     

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.     

Platinum(IV) complexes with purine analogs. Studies of molecular structure and antiproliferative activity in vitro

A series of tetrachloride platinum(IV) compounds of the general formulae PtCl₄L₂, where L = 1,2,4-triazolo[1,5-a]pyrimidine (tp) (1), 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp) (2), 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp) (3) and 5-methyl-1,2,4-triazolo[1,5-a]pyrimidin-7(4H)-one (HmtpO) (4) have been prepared and characterized by thermal analysis, ¹H, ¹³C, ¹⁵N, ¹⁹⁵Pt NMR and IR spectroscopy. Spectral data suggest that the triazolopyrimidines act as a monodentate ligand via the nitrogen atom N(3). The preliminary assessments of antitumor properties of the four complexes were evaluated as in vitro antiproliferative activity against three cell lines: HL-60 human acute promyelocytic leukemia, SW707 rectal adenocarcinoma and HCV29T bladder cancer. PtCl₄(dbtp)₂ exhibits high cytotoxic activity against all human cell lines, whereas the other complexes are only moderately active.