Theoretical Studies on Quantitative Structure-Activity Relationship and Structural Modification for 3-Substituted Sulfur-5（2-Hydr0xyphenyl）-4H-1,2,4-Triazole Compounds

用DFT-B3LYP方法,在基组6-31G水平,对24种3-取代硫基-5-（2-羟基苯基）-4H-1,2,4-三唑类化合物分子进行几何优化,并计算了EHOMO,ELUMO,ENHOMO,ENLUMO,QC1～QC8,QN1～QN3,QO,QS和ΔE1,ΔE2,ΣQ等量子化学描述符（qc）.通过最佳变量子集回归建立13种上述化合物对大肠杆菌、白色念珠菌、金黄色葡萄球菌等抑菌活性（AJ：Ae,Am和As）的QSAR模型.对于大肠杆菌的Ae模型的相关系数（R2）和逐一剔除法交叉验证系数Rcv2依次为0.930和0.871,相应白色念珠菌Am模型为0.926和0.869,As模型为0.781和0.572.通过Radj2,F,Rcv2,VIF,AIC,FIT等检验,上述模型具有令人满意的稳健性和预测能力.结果显示ΔE1和ΣQ直接影响这些化合物的生物活性：ΣQ增大,其抑菌活性增强;ΔE1越高,AJ下降.据此提出三唑类化合物分子可能的抑菌机理.由此发现,在三唑类化合物分子的R中合适部位选用吸电子能力较强的取代基团进行结构修饰,有利于提高被修饰后分子的抑菌活性.根据对R进行结构修饰（共提出11种化合物）,得出4种抑菌活性均超出100%的三唑类化合物（质量分数为0.01%）,希望将来得到生物实验的证实.     

Quantitative Correlation of the Acute Toxicity of Phenylthio-carboxylates with Their Structural and Thermodynamic Parameters by DFT Calculation

1 INTRODUCTION As industrial raw materials and pesticide, thio-ether, sulfoxide and sulfone have been used moreand more extensively. On the other hand, they havealso attracted chemists’ much attention due to theirpotential environmental hazards. Quantitative struc-ture-activity relationship (QSAR) is an effective me-thod evaluating the hazards of organic chemicals[1].QSAR equation could be employed to forecast thebiological activity of unknown compounds, which issignificant for initia…     

苯砜基环烷酸酯类化合物的分子结构与色谱保留的定量关系

根据线性溶解能理论，导出一种理论线性溶解相关模型，应用该模型及量子化学ＡＭＩ算法计算的分子结构参数，得出苯砜基环烷酸酯类化合物的分子结构与色谱保留定量关系方程，这个方程可以应用于同类化合物在同样色谱条件下保留行为的预测。研究表明，该类化合物的容量因子随着分子平均极化率的增大而增大，随着偶极矩和的分子中与硫原子相键合的氧原子的净电荷的增大而减小。     

Correlation of Quantitative Structure and Inhibition Phytotoxicity for Aromatic Compounds Using Ab Initio Method

1 INTRODUCTION Quantitative structure-activity relationship (QSAR) is one of the necessary methods to evaluate the ha- zards of organic chemicals. QSAR equation could be employed to forecast the biological activity of un- known compounds, which is significant for initial screening and evaluation of toxic compounds[1]. Aro- matic compounds are toxic organic compounds with relatively low water solubility, and their structure- activity relationship has been investigated with AM1 method[2]…     

烷基苯酚类化合物的气相色谱保留值与其结构参数的定量关系

计算了44个烷基苯酚类化合物的组成、拓扑、几何、静电和量子化学等结构参数,运用启发式方法对这些结构参数进行筛选,得到了含3个变量的化合物的定量结构与色谱保留值的线性关系模型,同时以这3个变量作为支持向量机模型的输入变量建立非线性回归模型。两种方法的相关系数(R2 )分别为0.98和0.92,相应的均方根误差分别是0.99和2.77。通过对两种模型的稳定性和预测能力的比较,发现线性模型能够更好地反映烷基苯酚的气相色谱保留值与其结构参数之间的定量关系。在已知烷基苯酚类化合物结构参数的情况下,线性回归模型更有助于它们的色谱分析。     

Toxicity （-lgEC50） Measurement of the Fluorobenzene Derivants against Vibrio Qinghaiensis （Q67） and Their 2D,3D-QSAR Study

Toxicities (-lgEC50) of 16 fluorobenzene derivants against vibrio qinghaiensis (Q67) were measured systematically,and their quantum chemistry parameters were calculated at the B3LYP/6-311G** level. Based on the experimental toxicity data and quantum chemistry parameters,2D-QSAR model was proposed,which was validated by variance inflation factors (VIF),t-value and cross-validation method. At the mean time,comparative molecular force field (CoMFA) based on molecular simulation was used to investigate the toxicity of fluorobenzene derivants. Furthermore,the intoxicating mechanism of fluorobenzene derivants was discussed. To our interest,2D-QSAR and CoMFA models exhibit good prediction ability,with which the toxicity of similar compounds can be predicted. Finally,toxicities (-lgEC50) of 12 fluorobenzene derivants against vibrio qinghaiensis (Q67) were predicted with these models.     

1-取代-2-氨基苯并咪唑衍生物的理论计算及QSAR研究

在B3LYP/6-31＋g(d)计算水平下, 通过运用密度泛函理论(DFT)量子化学方法, 对7种1-取代-2-氨基苯并咪唑衍生物的电子结构特征进行了研究, 获得了它们的电离能、亲合能、化学硬度、化学软度、化学势、电负性、亲电性、分配系数、折射率、极化率、分子体积和分子表面积等参数. 结果表明, 在2-氨基苯并咪唑衍生物的1位引入取代基团, 对化合物的电荷布居和结构性质都有较大的影响|关联了定量结构-活性关系(QSAR), 7种化合物的半数致死量LD₅₀与极化率等有较好的相关性. 这些结果可为1-取代-2-氨基苯并咪唑衍生物的氧化代谢实验研究和毒性机理揭示等提供重要信息.