Cross‐coupling reactions using porous multipod Cu2O microcrystals as recoverable catalyst in aqueous media

Porous multipod Cu₂O microcrystals were found to be an efficient, highly recyclable and eco‐friendly catalyst for the cross‐coupling reactions of aryl halides and terminal alkynes with high yields in aqueous media. Noteworthy, the Cu₂O catalyst can be reused for several times without significant decrease in catalytic activity.     

Synthesis,properties and mechanism of photodegradation of core–shell structured upconversion luminescent NaYF4:Yb3+,Er3+@BiOCl

Microspherical bismuth oxychloride (BiOCl) can only utilize ultraviolet (UV) light to promote photocatalytic reactions. To overcome this limitation, a uniform and thin BiOCl nanosheet was synthesized with a particle size of about 200 nm. As results of UV–visible diffuse reflectance spectroscopy showed, the band gap of this nanostructure was reduced to 2.78 eV, indicating that the BiOCl nanosheet could absorb and utilize visible light. Furthermore, the upconversion material NaYF₄ doped with rare earth ions Yb³⁺ and Er³⁺ emitted visible light at 410 nm following excitation with near‐infrared (NIR) light (980 nm), which could be utilized by BiOCl to produce a photocatalytic reaction. To produce a high‐efficiency photocatalyst (NaYF₄:Yb³⁺,Er³⁺@BiOCl), BiOCl‐loaded NaYF₄:Yb³⁺,Er³⁺ was successfully synthesized via a simple two‐step hydrothermal method. The as‐synthesized material was confirmed using X‐ray diffraction, scanning electron microscopy, X‐ray photoelectron spectroscopy as well as other characterizations. The removal ratio of methylene blue by NaYF₄:Yb³⁺,Er³⁺@BiOCl was much higher than that of BiOCl alone. Recycling experiments verified the stability of NaYF₄:Yb³⁺,Er³⁺@BiOCl, which demonstrated excellent adsorption, strong visible‐light absorption and high electron–hole separation efficiency. Such properties are expected to be useful in practical applications, and a further understanding of the NIR‐light‐responsive photocatalytic mechanism of this new catalytic material would be conducive to improving its structural design and function.     

痫愈胶囊质量标准研究

制定了痫愈胶囊(天麻、僵蚕、黄芪、党参)的质量标准。用显微鉴别法鉴别僵蚕,用薄层色谱法鉴别黄芪、党参,用高效液相色谱法测定天麻素含量。天麻素含量在0.1036~2.072μg范围内呈良好的线性关系,r=0.9997。平均回收率为98.80%,相对标准偏差为0.94%(n=5)。鉴别方法、定量方法可用于该制剂的质量控制。     

Recent applications of radical cascade reaction in the synthesis of functionalized 1-indenones

1-Indenones are important scaffolds in natural products, biologically active molecules as well as functional materials. Recently, radical cascade cyclization has emerged as an efficient and powerful strategy for the construction of valuable and versatile functionalized 1-indenones. In this review, the recent advances of this rapidly growing area were summarized. The selected examples have been classified according to the type of reaction substrates such as 1,3-diarylpropynones, 2-alkynylbenzonitriles, arylpropynols, 1,5-enynes and 2-alkynylated bromocinnamates.     

Ugi/Diels-Alder串联反应在构建杂环化合物中的应用

杂环化合物广泛存在于天然产物和药物分子中,许多杂环化合物还具有潜在生物活性和药理作用。因此,如何快速高效地构建小分子杂环化合物库成为当今有机合成和药物化学领域的研究热点。Ugi反应在多样性导向合成方面具有得天独厚的优势,能够解决待合成化合物数量庞大、结构复杂的难题;同时,Diels-Alder [4+2]环加成反应能够高效构建碳-碳键,以较高的立体选择性和区域选择性合成六元环系。目前,集二者于一身的Ugi/Diels-Alder串联反应在构建杂环化合物方面展现出了巨大优势和无穷潜能。本文以不同类型的DA反应分类:按照呋喃作为双烯体、吡咯作为双烯体、噻吩为双烯体、口恶唑作为双烯体、 1,2,4-三嗪作为双烯体、苯作为双烯体、不饱和键和芳环共同作为双烯体等对UDA串联反应的研究进行了综述。     

Identification and characterization of forced degradation products and stability‐indicating assay for notoginsenosidefc by using UHPLC‐Q‐TOF‐MS and UHPLC‐MS/MS: Insights into stability profile and degradation pathways

Notoginsenoside Fc, a protopanaxadiol‐type saponin, shows multi‐pharmacological activities. Chemical stability evaluation plays a crucial role in drug development. In this study, the forced degradation behavior of Notoginsenoside Fc was investigated under hydrolytic and oxidative conditions. A specific ultra high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry was developed for the separation, identification, and characterization of the degradation products of Notoginsenoside Fc. Fifty potential degradation products were formed via deglycosylation, dehydration, hydration, isomerization, side‐chain cleaving, oxidation, and superoxidation. Notoginsenoside Fc was subjected to different pH solutions, temperatures, and time periods to assess its stability. A sensitive ultra high performance liquid chromatography‐tandem mass spectrometry was developed for the quantification of Notoginsenoside Fc, notoginsenoside ST‐4, notoginsenoside Ft1, and relative quantification of notoginsenoside Ft2, 20(R)‐notoginsenoside Ft2, notoginsenoside SFt3, and notoginsenoside SFt4. The assay was linear over the concentration range (R² > 0.997) with the lowest limit of quantification of 0.02 μg/mL for Notoginsenoside Fc, Notoginsenoside ST‐4, and Notoginsenoside Ft1. The intra‐day precision, inter‐day precision, and accuracy of the three analytes were within accepted levels. The degradation kinetics of Notoginsenoside Fc in pH 1 and 3 solutions fits to first‐ and second‐order kinetics, respectively. The degradation of Notoginsenoside Fc is pH‐, temperature‐, and time‐dependent.     

纳米ZnO/聚醋酸乙烯酯复合薄膜的光催化性能研究

采用溶胶-凝胶和浸渍-提拉而后煅烧的方法得到了在可见光作用下具有光催化性能的纳米ZnO/聚醋酸乙烯酯(PVAc)复合薄膜.通过正交设计实验,研究了PVAc的浓度、煅烧温度、煅烧时间、复合薄膜层数和附加ZnO膜层数等工艺因素对光催化性能的影响,并通过SEM,XRD和FT-IR对其进行了分析与表征.在室内普通照明用白炽灯作用下,以甲基橙溶液为催化对象,PVAc含量10%的、在250℃煅烧30min所得到的纳米ZnO/PVAe复合薄膜的光催化性能的实验结果表明,复合薄膜对甲基橙降解率达60%,而使用250℃煅烧30min所得到的纳米ZnO 4层薄膜或PVAc 4层薄膜催化的甲基橙溶液的浓度变化很小.     

电感耦合等离子体质谱（ICP-MS）法测定黄精中15种稀土元素及其指纹图谱绘制

为了准确测定黄精中稀土元素的含量,采用电感耦合等离子体质谱（ICP-MS）法同时测定黄精中15种稀土元素（La、Ce、Pr、Nd、Pm、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu）的含量,进而绘制稀土元素指纹图谱,以稀土元素含量的平均值构建黄精稀土元素标准指纹图谱,作为鉴定黄精中药材的参考依据。黄精样品采用微波消解法处理后,通过在线引入内标溶液,采用ICP-MS法测定15种稀土元素的含量,采用OriginPro 2021绘制稀土元素指纹图谱和进行主成分分析,采用SPSS 26.0进行聚类分析。15种稀土元素的线性关系、重复性、精密度良好,平均加标回收率在97.0%~103.3%,相对标准偏差小于等于1.74%。黄精中Ce、La、Nd含量相对较高,Ce含量为53.02～2004.58 μg/kg,位居第一。聚类分析和主成分分析结果表明,样品聚为2类,同一产地的样品能够较好地聚在一起。黄精药材中15种稀土元素的指纹图谱具有相似的分布形态,具有较强的特征性和一致性,相似度均大于0.950。该方法操作简单,准确可靠,能满足实验分析要求,可为黄精的质量控制和药理研究提供参考;建立的指纹图谱可用于黄精的鉴别。     

乙炔氢氯化均相催化反应动力学和机理的研究

本文研究了以HgCl₂为催化剂时乙炔氢氯化制氯乙烯均相反应的动力学。获得该反应速率方程为:r=k′[HgCl₂][H⁺]³[CH≡CH],表观活化能为13.6千卡/摩尔。根据实验结果提出了该催化反应的机理。