应用量化参数和CoM FA法研究苯甲酸类化合物的结构和其pK_a值的相关性

提取量子化学参数来表征苯甲酸类化合物的结构 ,应用多元回归方法和人工神经网法在该类化合物的结构和 p Ka 值间构造了二维空间的数学模型 ,并进一步运用 Co MFA法在三维空间进行研究。人工神经网络法和 Co MFA法获得了比较好的结果 ,同时 ,讨论了空间作用和静电作用对 p Ka值的影响。

拟除虫菊酯类农药结构/急性毒性的三维定量构效关系

用比较分子力场分析(CoMFA)研究了拟除虫菊酯类农药的结构与急性毒性DL50(大鼠,口服)的关系,考察了网格结构和探针原子对结果的影响。得到模型的R2为0 99,标准偏差为0 88,说明立体效应和静电作用场是描述拟除虫菊酯类农药急性毒性和进行结构活性关系研究的重要结构参数。在模型中,立体能与静电能的贡献为0 82/0 18,说明起主要作用的是立体项,建立三维定量构效关系模型可以对该类新化合物的DL50进行预测。构建的三维结构/毒性模型用三维等高图来表示,如果结合分子杀虫活性的相关研究,可以用来指导新分子的结构设计。

A QSAR of the toxicity of amino-benzenes and their structures

The quantum chemical parameters and the topological indices have been calculated for the prediction of the toxicity of amino-benzenes in the environment, and work has been done on the multiple regression and neural networks. The combination of CoMFA with formation heat yields greatly improved results. A good model has been obtained which provides a basis for the studies of the toxic action mechanism.

苯胺类化合物结构-毒性定量构效关系研究

为定量预测环境中有害有机苯胺类化合物的毒性 ,计算了量子参数和拓扑指数等 ,进行了回归分析和人工神经网计算 ,得到了较好的结果 .用CoMFA实施了三维构效关系研究 ,发现在常规CoMFA立体和静电参数的基础上 ,引进分子生成热 ,可使结果得到很大程度的改善 ,不仅可得到较好的定量数学模型 ,同时为探讨该类化合物毒性作用机理提供了依据.

三维分子特征的提取及苯胺类化合物结构—毒性相关性研究

在环境中有许多污染物,如多氯联苯,多环芳烃,DDT等,这些化合物具有难降解性,高脂溶性及易生物储积,所以潜在的毒性很大。本文侧重研究的是苯胺类化合物结构与性质相关性(QSAR)。 该类研究的关键是如何有效地表征化合的结构。从80年代以来,在定量构效关系研究中,陆续出现一些考虑生物活性分子与受体结合时三维结构的研究方法,统称为三维定量构效关系(3D-QSAR)研究。其中,最典型应用最普遍的3D-QSAR、方法之一是CoMFA方法。新近,在我们的研究中发现对于某些类的化合物,CoMFA适应性

A QSAR study of the antiallergic activities of substituted benzamides and their structures

Multiple regression analysis (MRA) and comparative molecular field analysis (CoMFA) have been used in studies of the correlation between the antiallergic activities of substituted benzamides and their structures. The results achieved using Coh IFA based on 3D factors are much better than those obtained using MRA based on mainly 2D structural information. The CoMFA results reveal that the steric effects are more important than the electrostatic effects for the activities of substituted benzamides. (C) 1999 Elsevier Science B.V. All rights reserved.

新型抗爱滋病药物吡喃酮类化合物的三维定量构效关系研究

吡喃酮类化合物是抗爱滋病的一类新药， 本文用CoMFA(Comparative Molecular Field Analysis)方法对19个吡喃酮类化合物的三维构效关系进行了研究， 较详细地探讨了分子的重叠方式， 并选用了其他有关的一些最优条件， 得到满意的结果。

Studies on quantitative structure-activity relationship between the structures of derivatives of benzamide and their antiallergic activities

Molecular connectivity index and comparative molecular field analysis (CoMFA) have been applied to the studies of the correlation of the derivatives of benzamide and their antiallergic activities. The results achieved by using CoMFA based on 3D factors are much better than that obtained by using multiple regression analysis based on majorly 2D structural information. The CoMFA results show that the dominant factor which affects activity is steric, whereas electrostatic effect only plays an unimportant role.

Studies on three-dimensional quantitative structure-activity relationship of PDE inhibitory activity of imidazopyridines

In recent years there has been a resurgence of interest in inhibitors of cyclic nucleotide phosphodiesterases (PDE) and enzymes responsible for the intracellular hydrolysis of the second messenger cAMP and cGMP. In this study, a series of 2-substituted phenyllimidazo[4,5-b]pyridines have been made to investigate 3D-QSAR of PDE activity using CoMFA. CoMFA resulted in a quantitative description of the major steric and electrostatic field effects, and gave significant new insights to factors governing PDE inhibition activity. The model was used to predict the PDE inhibition activity of imidazopyridines with satisfactory results.

甾类化合物的结构与抗炎活性相关性3D-QSAR研究

研究了甾族化合物的结构与抗炎活性相关性的三维构效关系，采用比较分子力场分析法（CoMFA）寻找结构与活性的关系，建立了一个可靠的构效关系模型，为活性分子的进一步修饰和改造提供了信息。

Studies on three-dimensional quantitative structure-activity relationships between the structures of N-nitroso compounds and their carcinogenic activities

Comparative molecular fiels analysis (CoMFA) has been applied to the studies of the correlation of the N-nitroso compounds and their carcinogenic activities, The comparison of CoMFA results with different lattice spacing and different atom probes was investigated, CoMFA resulted in a quantitative description of the major steric and electrostatic field effects and gave significant new insights to factors governing potency.

P2Y(1) antagonists: Combining receptor-based modeling and QSAR for a quantitative prediction of the biological activity based on consensus scoring

P2Y(1) is an ADP-activated G protein-coupled receptor (GPCR). Its antagonists impede platelet aggregation in vivo and are potential antithrombotic agents. Combining ligand and structure-based modeling we generated a consensus model (LIST-CM) correlating antagonist structures with their potencies. We docked 45 antagonists into our rhodopsin-based human P2Y(1) homology model and calculated docking scores and free binding energies with the Linear Interaction Energy (LIE) method in continuum-solvent. The resulting alignment was also used to build QSAR based on CoMFA, CoMSIA, and molecular descriptors. To benefit from the strength of each technique and compensate for their limitations, we generated our LIST-CM with a PLS regression based on the predictions of each methodology. A test set featuring untested substituents was synthesized and assayed in inhibition of 2-MeSADP-stimulated PLC activity and in radioligand binding. LIST-CM outperformed internal and external predictivity of any individual model to predict accurately the potency of 75% of the test set.

Molecular modeling of N-terminal domains of NMDA-receptor. Study of ligand binding with N-terminal domains

Using the molecular-graphic complex Sybyl6.7.2, computational construction of spatial models for N-terminal domains (of NR1- and NR2B-subunits) of NMDA-receptor was conducted. On the basis of the constructed models and also CoMFA method the conclusion is made about presence of the binding site for the compounds similar to iphenprodyl in two N-terminal domains of NR1- and NR2B-subunits. The obtained data can be used for constructing new ligands.

Synthesis and structure-activity relationship studies of CD4 down-modulating cyclotriazadisulfonamide (CADA) analogues

HIV attachment via the CD4 receptor is an important target for developing novel approaches to HIV chemotherapy. Cyclotriazadisulfonamide (CADA) inhibits HIV at submicromolar levels by specifically down-modulating cell-surface and intracellular CD4. An effective five-step synthesis of CADA in 30% overall yield is reported. This synthesis has also been modified to produce more than 50 analogues. Many tail-group analogues have been made by removing the benzyl tail of CADA and replacing it with various alkyl, acyl, alkoxycarbonyl and aminocarbonyl substituents. A series of sidearm analogues, including two unsymmetrical compounds, have also been prepared by modifying the CADA synthesis, replacing the toluenesulfonyl sidearms with other sulfonyl groups. Testing 30 of these compounds in MT-4 cells shows a wide range of CD4 down-modulation potency, which correlates with ability to inhibit HIV-1. Three-dimensional quantitative structure-activity relationship (3D-QSAR) models were constructed using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) approaches. The X-ray crystal structures of four compounds, including CADA, show the same major conformation of the central 12-membered ring. The solid-state structure of CADA was energy minimized and used to generate the remaining 29 structures, which were similarly minimized and aligned to produce the 3D-QSAR models. Both models indicate that steric bulk of the tail group, and, to a lesser extent, the sidearms mainly determine CD4 down-modulation potency in this series of compounds.

Role of Halogen Bonds in Thyroid Hormone Receptor Selectivity: Pharmacophore-Based 3D-QSSR Studies

Most physiological effects of thyroid hormones are mediated by the two thyroid hormone receptor subtypes, TR alpha and TR beta. Several pharmacological effects mediated by TR beta might be beneficial in important medical conditions such as obesity, hypercholesterolemia and diabetes, and selective TR beta activation may elicit these effects while maintaining an acceptable safety profile, To understand the molecular determinants of affinity and subtype selectivity of TR ligands, we have successfully employed a ligand- and structure-guided pharmacophore-based approach to obtain the molecular alignment of a large series of thyromimetics. Statistically reliable three-dimensional quantitative structure-activity relationship (3D-QSAR) and three-dimensional quantitative structure-selectivity relationship (3D-QSSR) models were obtained using the comparative molecular field analysis (CoMFA) method, and the visual analyses of the contour maps drew attention to a number of possible opportunities for the development of analogs with improved affinity and selectivity. Furthermore, the 3D-QSSR analysis allowed the identification of a novel and previously unmentioned halogen bond, bringing new insights to the mechanism of activity and selectivity of thyromimetics.