白藜芦醇的合成新方法

本文探索了合成白藜芦醇的新方法。以3,5-二甲氧基苯胺为原料,经重氮化、还原及乙酰化得到中间体N′-乙酰基-3,5-二甲氧基苯肼(4),中间体4与4-甲氧基苯乙烯经Mizoroki-Heck偶联反应得中间体5,脱去甲基即得到目标产物白藜芦醇,总收率约31.9%。中间体及目标产物的结构均经质谱及核磁氢谱确证。该路线操作简便、条件温和,可用于白藜芦醇的放大制备。     

用于一氧化氮检测的小分子荧光探针研究进展

生物小分子NO以其重要的生理学和病理学作用受到科学家们的广泛关注。高选择性、高灵敏度、低毒性NO分子荧光探针的设计和开发,在环境检测、食品安全及人体内NO检测等领域具有重要意义。本文以小分子荧光探针对NO的识别机制为主线,从唑环的形成、螺内酰胺开环、还原脱氨、二氢吡啶的芳构化、NO与金属络合物的反应、与非金属Se的反应和亚硝胺的形成出发,综述了近年来NO小分子荧光探针的研究进展。对NO探针设计及其识别性能研究方面的工作进行了总结,并讨论了NO荧光探针今后的设计思路和重点研究方向。     

[1,2,4]三唑并[3,4-b][1,3,4]噻二嗪类衍生物的合成及生物活性研究进展

[1,2,4]三唑并[3,4-b][1,3,4]噻二嗪作为极具前景的活性基团,在抗菌、抗肿瘤等方面具有多种药理活性,在药物和化学领域受到了广泛的关注。本文以含三唑并噻二嗪结构化合物的合成及其在抗肿瘤、抗菌等方面的生物活性为依据,对近几年国内外关于[1,2,4]三唑并[3,4-b][1,3,4]噻二嗪类化合物的研究进行分析总结,以期为后续该类新型抗肿瘤化合物的设计合成提供参考。     

Fabrication of Boron Nitride Nanosheets by Exfoliation

Nanomaterials with layered structures, with their intriguing properties, are of great research interest nowadays. As one of the primary two‐dimensional nanomaterials, the hexagonal boron nitride nanosheet (BNNS, also called white graphene), which is an analogue of graphene, possesses various attractive properties, such as high intrinsic thermal conductivity, excellent chemical and thermal stability, and electrical insulation properties. After being discovered, it has been one of the most intensively studied two‐dimensional non‐carbon nanomaterials and has been applied in a wide range of applications. To support the exploration of applications of BNNSs, exfoliation, as one of the most promising approaches to realize large‐scale production of BNNSs, has been intensively investigated. In this review, methods to yield BNNSs by exfoliation will be summarized and compared with other potential fabrication methods of BNNSs. In addition, the future prospects of the exfoliation of h‐BN will also be discussed.     

Red-emitting salicylaldehyde Schiff base with AIE behaviour and large Stokes shift

Three salicylaldehyde Schiff base (SSB) with AIE behavior were designed and facilely synthesized through a condensation reaction. In solid and aggregation states, these SSB dyes exhibited yellow to red emission with large Stokes shift. One of SSB dyes could specifically stain lipid droplets in living cells.     

Characterization of a Stable Adaptive Calibration Model Using Near-Infrared Spectroscopy and Partial Least Squares with a Kalman Filter

The calibration model of near-infrared (NIR) spectra established using the Kalman filter-partial least square (partial least squares combined with a Kalman filter) method can be adapted to outdated equipment, environmental changes, external samples, and other applications. However, the variance of the measurement noise estimation for NIR spectrum measurements cannot be easily obtained using Kalman filter-partial least squares; therefore, the variance in the measurement noise is often assumed to be zero for the Kalman filter-partial least square calibration model, which affects the stability of the model. In this study, the measured input and output data were used effectively, and the gamma test method for estimating the measurement noise variance was used to improve the stability of the Kalman filter-partial least square calibration model. First, an accurate estimation of the measurement noise variance was obtained, and accurate modeling was then performed using Kalman filter-partial least squares. Finally, 600 abandoned drilling fluid samples were used to confirm the validity of the proposed method. The Kalman filter-partial least square and gamma test-Kalman filter-partial least square methods are compared. Testing of external samples 401–600 demonstrated that the stability of the Kalman filter-partial least square model decreased. The root mean square error of the prediction of the Kalman filter-partial least square model was 27.135, which was worse than that of the gamma test-Kalman filter-partial least square model (20.307). The validation results show that the proposed method has better stability in tracking the evolution of the NIR spectrometer’s measurement state.     

Enhanced Photodynamic Therapy by Reduced Levels of Intracellular Glutathione Obtained By Employing a Nano‐MOF with CuII as the Active Center

In photodynamic therapy (PDT), the level of reactive oxygen species (ROS) produced in the cell directly determines the therapeutic effect. Improvement in ROS concentration can be realized by reducing the glutathione (GSH) level or increasing the amount of photosensitizer. However, excessive amounts photosensitizer may cause side effects. Therefore, the development of photosensitizers that reduce GSH levels through synergistically improving ROS concentration in order to strengthen the efficacy of PDT for tumor is important. We report a nano‐metal–organic framework (Cu^II‐metalated nano‐MOF {CuL‐[AlOH]₂}_n (MOF‐2, H₆L=mesotetrakis(4‐carboxylphenyl)porphyrin)) based on Cu^II as the active center for PDT. This MOF‐2 is readily taken up by breast cancer cells, and high levels of ROS are generated under light irradiation. Meanwhile, intracellular GSH is considerably decreased owing to absorption on MOF‐2; this synergistically increases ROS concentration and accelerates apoptosis, thereby enhancing the effect of PDT. Notably, based on the direct adsorption of GSH, MOF‐2 showed a comparable effect with the commercial antitumor drug camptothecin in a mouse breast cancer model. This work provides strong evidence for MOF‐2 as a promising new PDT candidate and anticancer drug.     

One-pot synthesis of peony-like Bi2S3/BiVO4(040) with high photocatalytic activity for glyphosate degradation under visible light irradiation

In this work, samples consisting of BiVO₄ with exposed (040) facets coupled with Bi₂S₃ (Bi₂S₃/BiVO₄) were prepared through a one-pot hydrothermal method, using ethylenediaminetetraacetic acid as directing agent and L-cysteine as sulfur source and soft template. X-ray diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy measurements indicated that the Bi₂S₃ content had a significant influence on the growth of (040) and (121) facets as well as on the morphology of the Bi₂S₃/BiVO₄ samples. When the Bi₂S₃ content reached 1 mmol, the Bi₂S₃/BiVO₄ samples exhibited a peony-like morphology. The results of transient photocurrent tests and electrochemical impedance spectroscopy measurements confirmed that a more effective charge separation and a faster interfacial charge transfer occurred in Bi₂S₃/BiVO₄ than BiVO₄. The enhanced photocatalytic activity of the Bi₂S₃/BiVO₄ samples could be attributed to the improved absorption capability in the visible light region and the enhanced electron-hole pair separation efficiency due to the formation of the Bi₂S₃/BiVO₄ heterostructure. In addition, the Bi₂S₃/BiVO₄ samples showed relative stability and reusability. The simple method presented in this work could be used to fabricate composite photocatalysts with high activity for different applications, such as photocatalytic degradation of organic pollutants, photocatalytic splitting of water, and photocatalytic reduction of carbon dioxide.     

聚左旋乳酸/聚消旋乳酸共混物的结晶行为

非晶态聚消旋乳酸(PDLLA)对PLLA的结晶行为有较大的影响。本文利用差示扫描量热仪(DSC)和偏光显微镜(POM)对不同分子量PLLA、PDLLA按不同比例制得的共混物结晶进行了系统研究。结果表明随PDLLA含量的增大PLLA冷结晶温度升高,且越接近熔融温度。PDLLA分子量较小时PLLA球晶特征被明显破坏,PDLLA分子量较大时PLLA更易形保持球晶特征且易形成环带球晶形貌,这与结晶速率与非晶组分的扩散速率匹配程度有关。低分子量的PDLLA使PLLA的最大生长速率对应的温度出现在较低温度。     

CRBN调节剂Avadomide的合成工艺优化

Avadomide是处于Ⅱ期临床阶段用于治疗晚期实体瘤的潜在药物,本文对其合成工艺进行了研究,并对重要中间体的合成工艺进行了优化。以3-硝基邻苯二甲酰亚胺为起始原料,依次经开环、霍夫曼降解、环化、酯的氨解反应、氢氧化钯/碳加氢还原反应得到Avadomide,总收率为46.9%,产物结构经~1H NMR、~(13)C NMR和HRMS表征,纯度经HPLC检测为99.5%。优化后的工艺路线具有反应条件温和、后处理简单、产率高、可操作性强等特点,更适合Avadomide的工业化生产。