Biological Activity Relationship of Cyclic and Noncyclic Alkanes Using Quantum Molecular Descriptors

A 3-Dimension-Quantitative Structure-Activity Relationship (3D-QSAR1) approach is applied for the prediction of accurate chemical products made from biological activity and toxicity. Quantum chemical technique allows the construction of the molecular descriptors. The molecular quantum descriptors are classified into five principal component factors. Various linear regression equations are obtained using the statistical technique. In this study, the researchers propose the three best regression equations based on quantum molecular descriptors discussed earlier in this study. The observed EC50 vs calculated EC50 is plotted using the best fitting with the quantum descriptors.

Quantum Chemistry Prediction of Molecular Lipophilicity Using Semi-Empirical AM1 and <i>Ab Initio</i>HF/6-311++G Levels

Reliable prediction of lipophilicity in organic compounds involves molecular descriptors determination. In this work, the lipophilicity of a set of twenty-three molecules has been determined using up to eleven quantum various descriptors calculated by means of quantum chemistry methods. According to Quantitative Structure Property Relationship (QSPR) methods, a first set of fourteen molecules was used as training set whereas a second set of nine molecules was used as test set. Calculations made at AM1 and HF/6-311++G theories levels have led to establish a QSPR relation able to predict molecular lipophilicity with over 95% confidence.

量子化参数和分子价连接性指数对脂肪醇的QSPR/QSAR的相关性研究

根据分子中成键原子i的结构特征和所处的化学环境,新定义了原子i的点价iAδ,以价连接矩阵为基础构建了新的结构信息价连接性指数mA,并与量子化参数Qc结合,利用线性回归技术分别建立59个脂肪醇化合物的mAi和Qc与这些物质的QSPR/QSAR相关关系模型.新模型物理意义明确,计算简便,对脂肪醇化合物不同理化活性具有良好的估算和预测能力,复相关系数R>0.99,计算值与实验值均较好的吻合.

Mechanistic, Energetic and Structural Aspects of the Adsorption of Carmustine on the Functionalized Carbon Nanotubes

Using density functional theory, noncovalent interactions and two mechanisms of covalent functionalization of drug carmustine with functionalized carbon nanotube（CNT） have been investigated. Quantum molecular descriptors of noncovalent configurations were studied. It was specified that binding of drug carmustine with functionalized CNT is thermodynamically suitable. NTCOOH and NTCOCl can bond to the NH group of carmustine through OH（COOH mechanism） and Cl（COCl mechanism） groups, respectively. The activation energies, activation enthalpies and activation Gibbs free energies of two pathways were calculated and compared with each other. The activation parameters related to COOH mechanism are higher than those related to COCl mechanism, and therefore COCl mechanism is suitable for covalent functionalization. COOH functionalized CNT（NTCOOH） has more binding energy than COCl functionalized CNT（NTCOCl） and can act as a favorable system for carmustine drug delivery within biological and chemical systems（noncovalent）. These results could be generalized to other similar drugs.

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。

Quantitative Structure-activity Relationship Models of Monomer Reactivity

The reactivity parameters,Q and e,in the Q-e scheme reflect the reactivities of a monomer(or a radical)in free-radical copolymerizations.By applying multiple linear regression(MLR)analysis,the optimal quantitative structure-activity relationship(QSAR)model for the reactivity parameter lnQ was developed based on five descriptors(NAF,NOF,EαLUMO,EβHOMO,and EβLUMO)and 69 monomers with the root mean square(rms)error of 0.61.The optimal MLR model of the parameter e obtained from five descriptors(TOcl,NpN,NSO,EαHOMO and DH)and 68 monomers produced rms error of 0.42.Compared with previous models,the two optimal MLR models in this paper show satisfactory statistical characteristics.The feasibility of combining 2D descriptors obtained from the monomers and 3D descriptors calculated from the radical structures(formed from monomers+H )to predict parameters Q and e has been demonstrated.