QSAR based modeling of inhibitory activity of alkenyldiarylmethane derivatives

A series of alkenyldiarylmethanes (ADAMs) were subjected to QSAR analysis by using linear free energy relationship model of Hansch. QSAR has been developed using steric, electronic and topological parameters along with appropriate dummy variable. Statistical techniques were applied to identify the structural and physicochemical requirements for ADAMs. The results are critically discussed on the basis of regression data and cross-validation techniques.     

Conformational Parameters of the Sandalwood-Odor Activity: Conformational calculations on sandalwood odor

The conformational parameters responsible for sandalwood odor were investigated by the “active-analog approach”. The pharmacophoric (osmophoric) pattern of sandalwood-odor molecules can be outlined as three points: the OH group (point PI), a lipophilic group (point P2) 2.9–3.0 Å distant from the OH group, and a bulky rigid group (point P3), represented as a dummy atom in the middle of the alicyclic system (norbornane bicycle or cyclopentene ring) or a quaternary C-atom. This concept was tested on a series of representative sandalwood-odor compounds and on some structurally similar, but odorless substances.     

Design of new imidazole derivatives with anti-HCMV activity: QSAR modeling,synthesis and biological testing

Journal of Computer-Aided Molecular Design - The problem of designing new antiviral drugs against Human Cytomegalovirus (HCMV) was addressed using the Online Chemical Modeling Environment (OCHEM)....     

Study of the structural and electronic origin of the sandalwood odor of some terpenylcyclohexanols

Abstract  

The correlation between structural and electronic features and the sandalwood odor of some terpenylcyclohexanols is established on the basis of quantum chemical calculation methods. A definite structural fragment with electronic properties determining the origin of the odor is revealed. The effects of HOMO–LUMO energy gaps and total energies of some terpenylcyclohexanols on their odor intensity are investigated.     

QSAR modeling with the electrotopological state indices: Corticosteroids

A structure-activity analysis of a series of steroids binding to corticosteroid-binding globulin was made using the electrotopological state index for each atom in the molecule. Two indices were found to correlate well with the binding affinity. The indices encode structural characteristics in the A and the D rings of the steroids in the study. One of the indices was formulated as the difference between two indices in the A ring. The two were not intercorrelated, suggesting that the composite index signals the influence of structure changes in or near the A ring that can be monitored by the composite index. This is a new observation using this structure-activity method. It is suggested that this model makes some contributions towards detection of the pharmacophore.     

QSAR based modeling on a series of lactam fused chroman derivatives as selective 5-HT transporters

One of the most prevalent disorders in the present society is depression. The development of treatments for this disorder, beginning with the tricyclic antidepressants and leading to the development of selective serotonin re-uptake inhibitors, has focused on compounds that block the function of the serotonin transporter (SERT). Quantitative structure–activity relationship has been performed on a series of lactam fused chroman derivatives as selective 5-HT transporters, using different physicochemical parameters along with appropriate indicator variables. It has been found that physicochemical parameters, such as connectivity indices ⁰χ and ²χ, molecular weight (MW), Parachor (Pc), Balaban index (J), Wiener index (W) along with indicator variables are significantly correlated with activity. In this paper best results were obtained by using multiple regression analysis. Different models were generated with high values of R² and low values of PRESS/SSY ratio. The significant equations were statistically tested by using leave one out (LOO) technique and cross-validation methods.     

A rapid method for molecular shape comparison of medium-sized molecules. Conformational calculations on sandalwood odor,IV

Summary A fast method of a surface comparison of two or more molecules to be matched is presented. The Van der Waals surfaces of molecules are described by points calculated as the intersection of grid lines with the molecular surface. The mean surface of various molecules with the same biological activity can be constructed. It is used for further comparisons with similar molecules lacking this activity. Deviations of any molecular surface from the mean surface can be mapped onto the surface. The method was tested on a distinct group of sandalwood odor molecules and it was shown that such matching and comparison procedures are useful in the investigation of odor structure-activity relationships proposed as CAFD (computer aided fragrance design).Dedicated to Prof. Dr. W. Fleischhacker, on occasion of his 60th anniversary     

QSAR modeling of large heterogeneous sets of molecules

In aquatic toxicology, QSAR models are generally designed for chemicals presenting the same mode of toxic action. Their proper use provides good simulation results. Problems arise when the mechanism of toxicity of a chemical is not clearly identified. Indeed, in that case, the inappropriate application of a specific QSAR model can lead to a dramatic error in the toxicity estimation. With the advent of powerful computers and easy access to them, and the introduction of soft modeling and artificial intelligence in SAR and QSAR, radically different models, designed from large noncongeneric sets of chemicals have been proposed. Some of these new QSAR models are reviewed and their originality, advantages, and limitations are stressed.     

Application to QSAR studies of 2-furylethylene derivatives

A quantitative structure–activity relationship (QSAR) is a mathematical model that relates a molecular structure to a physicochemical property or a biological activity. The log P of a set of 38 of 2-furylethylenes, biologically active substances exhibiting a broad spectrum of antimicrobial, antiparasitic, cytotoxic, carcinogenic and mutagenic activities, was modeled by using topological indices provided by TOPOCLUJ and DRAGON software packages. The models derived showed good stability and predictability (as given by the leave-one-out LOO cross-validation data). The results are compared with those reported in literature, obtained by different methodology.     

苯胺衍生物式电位的QSAR研究

以AM1量子化学半经验分子轨道方法计算22个苯胺衍生物的分子结构参数,用多元线性回归的方法研究了13个式电位已知的苯胺衍生物的氧化式电位与其分子结构参数之间的关系.苯胺衍生物式电位与离子化电势(Ip),N原子上的净电荷(e(N),总的偶极矩(μt)和第四个碳上的净电荷(e(C4))有很好的相关性,回归方程为:E0′=-7.820 5 0.884 9(Ip-3.739(e(N)-0.093 56μt 0.925 1(e(C4)),(R=0.979,SD为0.023 6).依据回归方程合理地预测了其余9个苯胺衍生物的离子化电势和式电位,探讨了取代基性质和取代位置对离子化电势和式电位的影响.     

5,8-二甲基乙酰紫草素衍生物QSAR及分子设计

综合运用密度泛函理论、分子力学、统计学及比较分子力场分析等方法研究了抗肿瘤药物5,8-二甲基乙酰紫草素衍生物的二维(2D)、三维(3D)定量构效关系(QSAR).所建最优2D-QSAR方程的交叉验证系数(q2)和拟合相关系数(R2)分别为0.618和0.736.CoMFA模型的q2和非交叉验证系数(r2)分别为0.703和0.982,预测相关系数R2pred为0.746.结果表明,所建立的2D/3D-QSAR模型都具有良好的统计学意义及合理、可信的预报能力,可以预测未知化合物的活性。基于此研究结果,设计了4个具有较高抗肿瘤活性的新化合物.