MICROCHIMICA ACTA
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2020
·Vol. 187
·期 6
·1-9
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IF 6.232
Li Wanying,Qian Hui,Liu Rui,Zhao Xiaoli,Tang Zhi,Huang Xianhuai,Li Weihua,Chen Xiaoming,Xie Fazhi,Zou Wensheng,Qu Qishu
Based on a detailed study of the hydrolysis process of tetrabutyl orthotitanate (TBOT), TiO 2 nanoclusters were modified inside the pores of SiO 2 core-shell particles instead of the outside. The pore size distribution of SiO 2 core-shell spheres modified with TiO 2 (SiO 2 @ d SiO 2 @TiO 2 ) was analyzed by Barrett-Joyner-Halenda (BJH) method and density functional theory (DFT) method, respectively. The results of the DFT calculations demonstrate that the TiO 2 nanoclusters are always first formed in bulk solution and then enter the pores. By regulating the rate of hydrolysis of TBOT, almost all of the TiO 2 nanoclusters are modified into the pores and the structure of the original SiO 2 core-shell sphere is hardly affected. The morphology of the particles was characterized by scanning electron microscopy and transmission electron microscopy. The crystal phase of TiO 2 was measured by XRD. SiO 2 @ d SiO 2 @TiO 2 spheres functionalized with C18 were packed into a stainless steel column. The chemical stability of SiO 2 @ d SiO 2 @TiO 2 spheres under alkaline was tested by flushing of a mobile phase at pH 13 for 7 days. The efficiency of the column after the alkali solution treatment still reaches 98,430 plates m −1 , which is only about 1.6% lower than that before the alkali solution treatment. A series of basic and acidic analytes were also separated on the column.
TiO 2 nanocrystals were coated into the pore of core-shell silica spheres. The prepared particles were packed into the column and separation performance up to 98,430 plates per meter was achieved.
研究领域:
材料科学
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分析化学
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PubMed
高影响因子
CHIRALITY
·
2021
·Vol. 33
·期 10
·643-651
·
IF 2.437
Yixiao Yan,Senmei Zhu,Xuna Luo,Yu Rao,Jinlong Su,Guantao He,Hansen Lin
We synthesized the optically active epineoclausenamide by utilizing chiral reagents, such as R -α-methylbenzylamine and S- α-methylbenzylamine, for the resolution of the intermediate ( trans -3-phenyl-oxiranecarboxylic acid 12 ), followed by amide exchange, cyclization, and reduction, unlike previously reported methods. The Meerwein–Ponndorf–Verley reduction was used to asymmetrically reduce neoclausenamidone. A plausible reduction mechanism of this method was elucidated. Thereafter, high-performance liquid chromatography (HPLC) was investigated for the resolution of the epineoclausenamide enantiomers. HPLC was also used to determine the optical purity of these isomers. Two chiral stationary phases (CSPs) for separating the enantiomers were compared. Different mobile phase compositions were tested at 298.15 K. The results showed that the best separation was obtained when the mobile phase was composed of n -hexane and isopropanol (IPA) (75/25, v/v), the racemate was separated on a Chiralcel OJ-H column, and the flow rate was 1.0 mL/min at a wavelength of 210 nm and a temperature of 25°C. The enantiomeric ratio (e.r.) values of both the synthetic (−)-epineoclausenamide and (+)-epineoclausenamide were 1.3(+):98.7(−) and 99.3(+):0.7(−), respectively. In this study, a new synthetic route was designed with a yield of 12.3–14.1%, and a quick (8 min) effective separation method was obtained. This provides basis for pharmacological research and quality control of clausenamide analogues.
研究领域:
有机化学
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药物化学
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分析化学
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PubMed
高影响因子
FOOD SCIENCE AND TECHNOLOGY RESEARCH
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2021
·
IF 0.668
Danwei Yue,Weirong Cai,Bole Ding,Han Zhu,Jingjing Li,Yin Zhu
Flos Dolichoris Lablab, as a flower of a homologous plant with medicinal and food applications, has rich plant activity with research value. In this article, we studied flavonoids in Flos Dolichoris Lablab, and an effective semipreparative HPLC separation method was established. Then, seven flavonoids from Flos Dolichoris Lablab were prepared in one step, and their antioxidant activity was evaluated. The results show for the first time that the seven flavonoids kaempferol 3-O-sophoroside (1), quercetin 3-rutinoside (2), quercetin 3-glucoside (3), kaempferol-3-O-robinobioside (4), kaempferol-3-O-rutinoside (5), isorhamnetin 3-O-neohesperidoside (6), and kaempferol-3-O-galactoside (7) were isolated from the genus Lablab. Antioxidant activity results with individual compounds show that compounds 2, 3, and 7 exhibit better antioxidant activity. Experiments on different combinations of flavonoids of Flos Dolichoris Lablab indicate that the interaction of flavonoids can affect the mixture's total antioxidant activity. This research provides guidelines for preparing flavonoids present in Flos Dolichoris Lablab and structure-activity relationship studies.
研究领域:
植物化学
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药理学
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天然产物研究
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高影响因子
NATURAL PRODUCT RESEARCH
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2020
·
IF 2.158
Yu-Xi Wang,Bin Lin,Le Zhou,Zhi-Yang Yan,Han Zhang,Xiao-Xiao Huang,Shao-Jiang Song
The phytochemical investigation on the twigs and leaves of Archidendron clypearia (Jack) I.C.N. led to the isolation of three pairs of furolactone-type lignans enantiomers, including a pair of new compounds (1R,5S,6S)-Kachiranol (1a) and (1S,5R,6R)-Kachiranol (1b) and four known compounds (2a/2b and 3a/3b). Separation of the furolactone-type lignans enantiomeric mixtures was achieved using chiral HPLC for the first time. Their structures were determined by spectroscopic analysis and comparison between the experimental and calculated electronic circular dichroism (ECD) spectra. All optical pure compounds were evaluated for their inhibitory effects on β-amyloid aggregation by ThT assay. Among them, the inhibitory activity of the compound 1b (71.1%) was higher than the positive control (61.0%) and other compounds. In addition, molecular dynamics and molecular docking were employed to explore the binding relationship between the ligand and the receptor.
研究领域:
植物化学
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神经科学
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药物化学
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DOI
PubMed
高影响因子
MICROCHEMICAL JOURNAL
·
2023
·
IF 4.8
Cai-Fang Liu,Xiao-Yan Ran,Cheng Liu,Yu-lan Zhu,Yan-Rui Lu,Yu-Ping Yang,Bang-Jin Wang,Jun-Hui Zhang,Sheng-Ming Xie,Li-Ming Yuan:
Chiral metal–organic frameworks, an emerging type of chiral porous materials, possess many outstanding characteristics such as high surface area, tunable pore sizes, and good chemical stability. Herein, we prepared a chiral [Zn 2 (D-Cam) 2 (4,4′-bpy)] n @SiO 2 core–shell composite on the SiO 2 -NH 2 microspheres by an in-situ growth method. The prepared [Zn 2 (D-Cam) 2 (4,4′-bpy)] n @SiO 2 -packed column exhibited high-resolution separation of racemic compounds and positional isomers at a low column backpressure (9–12 bar). Twelve pairs of enantiomers including alcohols, amines, epoxides, ketones, and esters were well resolved with sharp peak shapes on the [Zn 2 (D-Cam) 2 (4,4́-bpy)] n @SiO 2 chromatographic column. Compared the separation performance of [Zn 2 (D-Cam) 2 (4,4́-bpy)] n @SiO 2 -packed column and two chromatographic columns (commercial Chiralpak AD-H column and as-prepared SiO 2 -NH 2 column), the [Zn 2 (D-Cam) 2 (4,4′-bpy)] n -packed column and the commercial Chiralpak AD-H column have a good complementarity in chiral separation, and it also offered better separation performance compared to the SiO 2 -NH 2 column for separating positional isomers. The effects of column temperature and analyte mass on the HPLC separation were investigated. Additionally, the [Zn 2 (D-Cam) 2 (4,4́-bpy)] n @SiO 2 packed column has good repeatability and stability for HPLC separation of enantiomers and positional isomers. The relatvive standard deviations (RSDs) for repeated separations of 2,2,2-trifluoro-1-(9-anthryl)ethanol and o , m , p -bromoaniline were less than 0.8 % and 1.2 % for the retention time and peak area, respectively. After continuous use for one month, the RSDs for the retention time and peak area of them were in the range of 1.1–1.3 % and 1.5–1.8 % (inter-day and intra-day, n = 5), respectively. This work also indicates that the chiral MOFs@SiO 2 composites are promising for HPLC separation.
研究领域:
分析化学
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材料科学
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色谱技术
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高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2016
·
IF 3.926
Xiao-Fei Gu,Yue Zhao,Kan Li,Meng-Xiang Su,Fang Yan,Bo Li,Ying-Xiang Du,Bin Di
Structure elucidation of volatile aromatic isomers at trace level has long been considered as an elusive task, due to their structural similarities and similar polarities, even with the aid of many spectroscopic techniques such as mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy. Single-crystal X-ray diffraction (SCD) is recognized as one of the most powerful structural elucidation techniques. The recently developed crystalline sponge method overcomes the intrinsic limitation of SCD that the target molecules must be single crystals, being able to analyze non-crystalline and trace-amount compounds without any special treatment. In order to investigate whether the crystalline sponge method could be used for the structure elucidation of closely related isomers or other volatile and even oily compounds in complex mixtures at trace level, we combined HPLC separation with the crystalline sponge method for X-ray crystallographic analysis. In this paper, two pairs of volatile aromatic isomers including cis / trans isomers of asarone and positional isomers of carvacrol and thymol, as well as the main volatile component in essential oil extracted from Acorus Tatarinowii , were first isolated by HPLC and encapsulated into the crystalline sponge then elucidated by X-ray crystallographic analysis. Direct observation of these volatile compounds by X-ray crystallography was achieved using only microgram quantities without crystallization or derivatization. Unambiguous identification of these compounds was realized without reference standards. This strategy offers a promising platform capable of providing high-confidence detailed structural information of closely related isomers as well as other volatile and even oily compounds in complex mixtures in microgram quantities.
研究领域:
分析化学
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晶体学
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药学
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PubMed
高影响因子
危险品化学品经营许可证（带存储）