QSAR/QSPR在POPs归趋与风险评价中的应用

持久性有机污染物(POPs)是目前备受国际社会关注的高危害性有机污染物,对它们的环境归趋分析和风险评价需要获得大量可靠的性质数据和毒性数据,而定量结构活性/性质相关(QSAR/QSPR)方法为快速有效地获得这些数据提供了可能性。QSAR/QSPR模型已在预测POPs的生物活性/性质,补充缺失的基础数据及探求POPs的环境过程机制和生态效应机理等方面得到了广泛应用,近年来也在新POPs物质的筛选、归趋模拟以及风险评价等方面有着更进一步的应用或潜在应用前景。本文介绍了QSAR/QSPR在POPs性质和生物活性预测中的基本应用及其在POPs归趋和风险评价中的扩展应用,并对QSAR/QSPR在POPs研究领域的应用前景进行了展望。     

表面活性剂的QSAR/QSPR研究进展*

本文综述了表面活性剂定量结构-活性/性质相关(QSAR/QSPR)研究的最新进展,以及相关结构描述符在表面活性剂QSAR/QSPR研究中的应用.重点介绍了表面活性剂的cmc和表面张力γ与分子结构的定量关系、离子型表面活性剂电荷分布的定量计算及其对胶体结构与性质的影响.对表面活性剂分子结构与活性/性质的定量相关研究的发展趋势进行了展望.     

离子液体的QSPR/QSAR研究

离子液体以其独特的性质广受关注,人们对其潜在的应用价值做了大量的研究,但对离子液体特性和结构与性质/活性相关的研究却很少。本文综述了离子液体定量结构-性质/活性相关(QSPR/QSAR)研究的最新进展,重点介绍了QSPR/QSAR的基本原理和离子液体的熔点、有机化合物在离子液体中的无限稀释活度系数、离子液体的界面张力、有机物在离子液体中的溶解系数和分配系数、离子液体的电导率和黏度以及离子液体的毒性等性质与分子结构的定量关系,并对离子液体分子结构与性质/活性的定量相关研究的发展趋势进行了展望。     

离子液体的定量结构-性质/活性研究

本文系统介绍了离子液体定量结构-性质/活性相关(QSPR/QSAR)的研究方法和步骤,综述了QSPR/QSAR在离子液体的熔点、有机物在离子液体中的无限稀释活度系数、离子液体的表面张力、离子液体的电导率、有机物在离子液体中的溶解度、离子液体的黏度以及离子液体的生物毒性和降解性等方面的最新研究进展,总结了该方法的优缺点,并对未来的研究趋势进行了展望。     

有机化合物的QSAR研究

QSAR即定量结构——活性相关,从研究化合物的分子结构入手,运用适当的描述符,选取合适的结构参数和理化参数,建立起结构和生物活性之间的定量关系。本文概述了进行有机物QSAR研究的必要性,QSAR的研究方法及其在环境科学方面的应用。     

定量结构-性质关系在分析化学中的应用研究进展

定量结构-性质关系研究应用理论计算方法和各种统计分析工具相结合,研究系列化合物的结构与其生物学性质和各种物理化学性质之间的定量函数关系．它不仅可以建立预测化合物的各种物理化学性质以及生物活性的理论,而且还可以发现和确定对化合物的各种性质起决定作用的结构因素,从而在分子水平上了解物质的微观结构对各种宏观性质的影响,在很多领域得到了广泛的应用．主要介绍定量结构—性质关系在分析化学中的应用研究,主要包括在色谱分析、毛细管电泳分析中的应用两大部分．     

关于烷烃异构体密度与拓扑指数间的定量关系问题——与王克强同志商榷

长期以来,利用图论方法根据化合物的结构特征生成的各种拓扑指数以研究定量结构活性关系(QSAR)与定量结构-性质关系(QSPR)一直是化学中十分活跃的领域。特别是对烷烃异构体,因其结构简单和各种物理化学性质数据齐全,成为各种拓扑指数产生和应用的基础。本刊在1988年第3期发表了倪才华等人(以下简称倪文)用Wiener指数W,P和碳原子总数N三个拓扑量来寻求烷烃异构体拓扑结构与密度的关系,得到计算烷烃分子的密度(D)的通式:     

定量结构-活性/性质相关性中变量的选择——正交变换法与最优子集回归法的比较

定量结构－活性／性质相关性（QSAR／QSPR）研究的基本依据是化合物的性质与结构具有相关性,所以只要有方法描述化合物的结构（得到X）就可与化合物的性质（作为Y）建立起数学模型,并由引模型预测未知化合物。由化合物的结构可衍生（即描述）出诸多变量,从统计学出发,希望用尽可能少的变量来表征尽可能多的信息（如多元回归分析）。过多的变量不仅计算量大,从而可以导致所得的数学模型不稳定,使预测结果较差^[1],而且不同变量的组合所得结果可能差别很大,由此需要对变量进行压缩和选择。虽然变量的选择是一个非常费时和复杂的工作,但变量选择的好坏对数学模型的稳定性及准确性有致关重要的影响,从某种角度上讲,它能决定一项QSAR／QSPR研究的成败。最简单的选择变量的方法是穷举组合法,但此方法的计算量非常大,特别是当变量数较大时,该方法是实际上是不可行的,尽管用于变量选择的方法已有报道,但问题尚有待进一步研究。本文侧重比较了正交变换法与变量最优子集回归法,得到了很有启示性的结果。     

化学中的人工神经网络法

反向传输人工神经网络是应用最为广泛的一种方法, 本文较详细地介绍了该种方法及其相关的问题, 同时给出了Kohonen 模型和Hopfield 网络的简单算法。关于神经网络在化学中的应用, 该文介绍了6 个方面: 定量结构2活性性质相关性(QSAR/QSPR )研究, 有机化合物结构解析, 光谱的数据处理, 化学反应性, 流程优化, 故障诊断及控制, 蛋白质结构。     

黄酮类化合物抑制MMP-9的定量结构-活性关系和结构修饰的理论研究

运用密度泛函理论(DFT)和线性回归分析等方法研究了黄酮类化合物抑制MMP-9的定量结构-活性关系(QSAR)和结构修饰. 研究发现, 黄酮类化合物抑制MMP-9的实验生物活性数据－lg EC₅₀值与计算获得的黄酮类化合物的最低空分子轨道能量及分子水合能之间均存在着良好的线性关系|留一法交叉验证结果表明, 所建立的两个相应的QSAR模型都具有良好的稳定性和预测能力. 进一步研究发现, 在黄酮类化合物分子的A环、B环和C环上的合适部位选用供电子能力较强、能降低分子水合能的取代基团对其进行结构修饰, 有利于提高修饰后的分子抑制MMP-9的生物活性. 根据对木犀草素(Luteolin)分子进行结构修饰的结果(共33种化合物), 我们提出了黄酮类化合物抑制MMP-9可能的作用机理, 并设计出8种经结构修饰后生物活性有显著提高的MMP-9抑制剂, 希望将来得到实验的证实.     

Quantitative Structure-Property Relationship: XXV. Boiling Points of Aliphatic Monohydric Alcohols. Reasons for the Different Boiling Points of Isomers and Their Compositionally Related Compounds

The quantitative structure-property relationship was used to calculate the boiling points of 74 aliphatic monohydric alcohols of various structures; the trends in the properties of isomers and their compositionally related compounds were explained with account for the “hot ends” effect.     

Internet software for the calculation of the lipophilicity and aqueous solubility of chemical compounds

In this paper we describe an Internet Java-based technology that allows scientists to make their analytical software available worldwide. The implementation of this technology is exemplified by programs for the calculation of the lipophilicity and water solubility of chemical compounds available at http://www.lnh.unil.ch/~itetko/logp. Both these molecular properties are key parameters in quantitative structure-activity relationship studies and are used to provide invaluable information for the overall understanding of the uptake distribution, biotransformation, and elimination of a wide variety of chemicals. The compounds can be analyzed in batch or single-compound mode. The single-compound analysis offers the possibility to compare our results with several popular lipophilicity calculation methods, including CLOGP, KOWWIN, and XLOGP. The chemical compounds are analyzed according to SMILES line notation that can be prepared with the JME molecular editor of Peter Ertl. Conversion to SMILES from 56 formats is also available using the molecular structure information interchange hub developed by Pat Walters and Matt Stahl.     

一类新型N型钙通道阻滞剂的比较定量构效关系研究

使用结构和量子化学参数对一系列N取代N-甲基二肽衍生物的N型钙通道阻滞活性进行了定量构效关系研究, 并使用SOMFA方法建立了三维定量构效关系模型. 结果表明分子的范德华体积和最低未占据轨道能量是影响化合物生物活性的主要因素. N原子上取代基的溶剂可及面积也对化合物的钙通道阻滞活性有重要影响. 三维定量构效关系模型进一步支持了以上结果. 这些研究结果可为设计更高活性的N型钙通道阻滞剂提供有价值的参考信息.     

Novel [1,2,4]triazolo[3,4-b][1,3,4]thiadiazine derivatives embedded with benzimidazole moiety as potent antioxidants

Fourteen novel [1,2,4]triazolo[3,4-b][1,3,4]thiadiazine derivatives bearing benzimidazole moiety ( 7a-n ) have been synthesized using the one-pot nitro reductive cyclization method. All the synthesized compounds were confirmed by ¹H nuclear magnetic resonance (¹H NMR), ¹³C NMR, fourier-transform infrared (FT-IR), mass spectrum, and elemental analyses. All the title compounds were subjected to in vitro antioxidant activity. The free radical scavenging activity of the compounds was examined using DPPH, nitric oxide, and superoxide radical scavenging methods. The results demonstrated that compound 3-(2-(3,4-dimethoxyphenyl)-1-propyl-1H-benzo[d]imidazol-5-yl)-6-4-tolyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine ( 7c ) was potent in scavenging both DPPH and nitric oxide radical with IC₅₀ values of 13.57 and 18.55 μg/ml when compared to the standard with IC₅₀ values of 23.75 and 23.14 μg/ml, respectively, which was due to the presence of electron-donating groups. The activity was found to decline when electron-donating groups were replaced by electron-withdrawing groups. Moderate scavenging activity was observed for the superoxide radical. Structure activity relationship and physiochemical properties were studied for all the derivatives.     

Preparative Solid-State Chemistry with High-Power CO2 Lasers

The establishment of solid state chemistry as an independent field, which also has had a stimulating effect on material sciences, is a consequence of the experimental skill of chemists. The development of new methods led to an abundance of new compounds, the characteristic properties of which are linked with the solid state. The reaction temperature plays an important role in the synthesis of solid compounds; therefore, it is not surprising that a large number of the newly developed experimental techniques involve methods which can produce high temperatures on the openended temperature scale. Since the development of the CO₂ laser, the solidstate chemist has an excellent heat source available, and with the power available today the range of high temperatures possible has been extended considerably. A way is now open for producing metastable, “entropy-supported” high-temperature compounds and substances with anomalous oxidation states and with macroscopic defects.     

Electrochemical Properties of Substituted 2‐Methyl‐1,4‐Naphthoquinones: Redox Behavior Predictions

In the context of the investigation of drug‐induced oxidative stress in parasitic cells, electrochemical properties of a focused library of polysubstituted menadione derivatives were studied by cyclic voltammetry. These values were used, together with compatible measurements from literature (quinones and related compounds), to build and evaluate a predictive structure–redox potential model (quantitative structure–property relationship, QSPR). Able to provide an online evaluation (through Web interface) of the oxidant character of quinones, the model is aimed to help chemists targeting their synthetic efforts towards analogues of desired redox properties     

Computational and Theoretical Chemistry in Structure-Reactivity Studies of Organophosphorus Compounds

Computational multivariation analysis, molecular orbital calculation as well as molecular mechanics study were used for the qualitative and quantitative evaluation of the relationship between chemical structure and reactivity of organophosphorus compounds.