Asymmetric synthesis of (R)-(−)-chlozolinate through a chemoenzymatic procedure

A new asymmetric synthesis of (R)-chlozolinate 1, an important antifungal agent, based on the enzymatic asymmetrization of diethyl 2-benzyloxy-2-methylmalonate, is reported.     

Chiral ligands derived from abrine. Part 7: Effect of O,S, N in aromatic ring substituents at C-1 on enantioselectivity induced by tetrahydro-β-carboline ligands in diethylzinc addition to aldehydes

The effect of O, S and N atoms in aromatic ring substituents at C-1 position of tetrahydro-β-carboline ligands on the enantioselectivity of diethylzinc additions to benzaldehyde was studied when esters or tertiary alcohol functions were present at C-3. A mechanism is proposed to explain why the ester ligands 2c and 2d, in which the pyridyl N atom is at C′-2 in 2c and at C′-3 in 2d, catalyzed the addition of diethylzinc to benzaldehyde to form the (R)- and (S)-enantiomers of 1-phenyl-1-propanol, respectively. An explanation was also proposed for the moderate enantioselectivity induced by tert-alcohol 3c versus the very small enantioselectivity induced by 3d, containing a 3-pyridyl function at C-1, during diethylzinc additions. A -CH₂-t-Bu substituent at C-1 leads to very high enantioselectivities.     

3-芳基-5-(2-呋喃基)-4, 5-二氢吡唑衍生物的合成及其生物活性评价

二氢吡唑类化合物是一类具有良好生物活性的五元杂环化合物。本文以2-呋喃甲醛和4-氟苯乙酮为原料,经羟醛缩合和取代反应生成4’-二甲氨基呋喃查尔酮(2)后,与水合肼环化得到二氢吡唑中间体(3),再酰化得到9个未见报道的5-(2-呋喃基)-3-芳基-4, 5-二氢-1H-吡唑衍生物(4a-4i),其结构经IR、₁H NMR和₁₃C NMR确证。分别采用小鼠巨噬细胞Raw264.7模型和DHHP法初步测试了目标化合物的体外抗炎活性和抗氧化活性,结果表明,部分化合物具有潜在的抗炎活性和清除自由基活性,特别是化合物4b和4c的抗炎活性与阳性对照药地塞米松活性相当(IC₅₀值分别为7.84μM和10.52μM),而化合物3、4b、4c和4d在浓度为4mg/mL时对DPPH自由基的清除率均超过90%。     

Baeckfrutones A–L,polymethylated phloroglucinol meroterpenoids from the twigs and leaves of Baeckea frutescens

Twelve new polymethylated phloroglucinol meroterpenoids (PPMs), baeckfrutones A–L (1–12), were isolated from the twigs and leaves of Baeckea frutescens. Their structures and absolute configurations were unambiguously established by extensive spectroscopic methods (HRESIMS, NMR, and ECD) and single crystal X-ray diffraction. PPM 1 is a rare PPM comprising enone-type phloroglucinol and α-phellandrene units, whereas 2–4, 6, and 7, are the first hybrids of enone-type phloroglucinol and sabinene moieties with different stereochemistry. (?)-2 and 11 showed remarkable cytotoxicities against DU145 and HCT116?cells with IC₅₀ values of 1.33 and 12.89?μM, respectively. 6, 7, (+)-9, and 10 displayed significant anti-inflammatory activity with inhibitory rates of 74.64, 75.37, 55.13, and 75.01% at the concentration of 50?μM, respectively.     

Bioactive triterpenoids from Sambucus javanica Blume

Abstract

A new triterpene, javablumine A (1) along with six known ones were isolated from the aerial parts of Sambucus javanica Blume. They were identified as 3β,23-dihydroxy-11α,12α-epoxy-urs-20(30)-en-28,13β-olide (1), ursolic acid (2), pomolic acid (3), oleanic acid (4), 2α-hydroxy-oleanolic acid (5), α-amyrin (6), and lupeol palmitate (7), respectively. Compounds 1 and 3 exhibited inhibitory effect against nitric oxide (NO) production in lipopolysaccharide (LPS)-activated RAW264.7 macrophage cell lines with IC₅₀ values of 17.4 and 26.2?μM, respectively.     

Anti-inflammatory spirobisnaphthalene natural products from a plant-derived endophytic fungus Edenia gomezpompae

Spirobisnaphthalenes comprise a relatively rare family of natural products that are normally isolated from fungi and occasionally from plants.Here we reported the discovery of seven new preussomerintype spirobisnaphthalenes,preussomerins YT1-YT7(1-7),and seven known ones(8-14),from the endophytic fungus Edenia gomezpompae,enriching the structural diversity of this family of natural products.Their structures were established by 1 D and 2 D NMR spectroscopy,HRESIMS analysis and comparison with previously reported compounds,with the absolute configurations of compounds 1 and2 being further confirmed by single-crystal X-ray diffraction using Cu Ka radiation.The antiinflammatory activities of all isolates were assessed by measuring the production of NO in LPS-induced RAW2 64.7 macrophage cells.Among them,compounds 8 and 13 exhibited potent inhibitory activities on the production of NO,with IC_(50) values of 2.61 and 1.32 μmol/L,respectively.     

FTIR结合SVR对三七总多糖含量快速预测

对中药进行快速质量控制,从整体层面反映中药的安全性与有效性具有重要意义。通过硫酸-苯酚显色反应测定三七总多糖含量,傅里叶变换红外光谱(FTIR)结合支持向量机回归(SVR)建立三七总多糖含量预测模型,以期为三七提供快速准确的质控方法。采集云南省12个产地60个三七样品的红外光谱,紫外分光光度法(UV-Vis)检测样品中总多糖含量。红外光谱经过二阶导数(2D)、正交信号校正(OSC)、小波变换(WT)和变量投影重要性(VIP)筛选等数据优化处理。SPXY算法将所有样本按2∶1的比例划分为训练集与预测集。训练集数据用于建立SVR预测模型,网格式搜索、遗传算法(GA)和粒子群优化算法(PSO)对SVR预测模型进行参数优化,预测集进一步对SVR模型的预测能力进行验证。结果显示：(1)葡萄糖标准品与三七总多糖在490 nm处存在最大共有吸收峰,490 nm可作为三七总多糖检测的定量波长;(2)文山丘北、曲靖师宗及红河蒙自等产地的三七总多糖含量较高,平均含量在25 mg·g-1以上;(3)分析3种参数优化模型的校正均方根误差(RMSEE)与预测均方根误差(RMSEP),与PSO优化模型相比,网格式搜索优化模型欠学习,GA优化模型过学习;(4)PSO-SVR模型对预测集数据预测效果最好,RMSEP=3.120 6,R2_pre=83.13%,预测值与紫外检测值接近。表明FTIR结合PSO-SVR模型能够对三七中总多糖含量进行快速准确的预测,为保证三七稳定、安全与有效用药提供数据。     

两个C19-二萜生物碱的结构鉴定和NMR信号归属

从剑川乌头（Aconitum handelianum）的根中分离得到两个C₁₉-二萜生物碱：高展花乌头宁（homochasmanine,化合物1）和14-去苯甲酰大渡乌碱（14-debenzoylfranchetine,化合物2）.采用1D和2D核磁共振（NMR）技术（包括¹H NMR、¹³C NMR、DEPT、¹H-¹H COSY、HSQC、HMBC和NOESY）对其进行结构鉴定,完整归属了这两个化合物的¹H和¹³C NMR信号.     

FT-MIR and UV–vis data fusion strategy for origins discrimination of wild Paris Polyphylla Smith var. yunnanensis

Paris Polyphylla Smith var. yunnanensis (Franch.) Hand.-Mazz has multiple therapeutic properties and the origins may affect clinical efficacy. Tracing the geographical origin is important to the authentication and quality assessment of this species. 177 wild samples collected from central, southeast and northwest Yunnan Province, China, were analyzed by single analytical method and data fusion strategies (low- and mid-levels) using Fourier transform mid-infrared (FT-MIR) and ultraviolet-visible (UV–vis) spectroscopies combined with chemometrics (partial least squares discrimination analysis (PLS-DA) and support vector machines grid search (SVM-GS)), for categorizing samples from different geographic origins. According to the results, mid-level data fusion strategy presented a better generalization performance and accuracy rates based on latent variables selected by PLS-DA than single analytical method and low-level data fusion strategy. Accuracy rates were almost 100% when both of the PLS-DA and SVM-GS were employed for classifying samples picked from southeast and northwest districts based on mid-level dataset. For samples collected from central of Yunnan where was divided into seven categories in this paper, the accuracy rates of training set and test set of PLS-DA and SVM-GS were preferable (>87%). Based on the mid-level data set, both of the classification results of PLS-DA and SVM-GS presented satisfying accuracy for 177 samples. Additionally, as small as possible parameters showed in mid-level data set, it suggested that this method was robust and generalized. Therefore, the comprehensive method was established for the origin traceability of wild P. Polyphylla Smith var. yunnanensis, which is meaningful for the quality control of herbal medicines.