Correlation of activity of 2-(X-benzyloxy)-4,6-dimethoxyacetophenones with topological indices and with the Hansch equation

Correlation of antibacterial activity of some N-[5-(2-furanyl)-2-methyl-4-oxo-4H-thieno[2,3-d]pyrimidin-3-yl]-carboxamide and 3-substituted-5-(2-furanyl)-2-methyl-3H-thieno[2,3-d]pyrimidin-4-ones with topological indices using Hansch analysis

The antimicrobial activity of the N-[5-(2-furanyl)-2-methyl-4-oxo-4H-theino[2,3-d]pyrimidin-3-y1]-carboxamides and 3-substituted-5-(2-furanyl)-2-methyl-3H-thieno[2,3-d]pyrimidin-4-ones was correlated with different topological indices using Hansch analysis. Good correlations were obtained through a simple regression equation with third order molecular connectivity index (3chi). The developed QSAR models were crossvalidated by leave-one-out technique.

Molecular Structure and QSAR Study on Antispasmodic Activity of some Xanthoxyline Derivatives

Semi-empirical molecular orbital calculations at AM1 level were done with the aim to investigate the structure-activity relationships of antispasmodic activities of ten 2-(X-benzyloxy)-4,6-dimethoxyacetophenones with X = H, 4'-F, 4'-NO2, 4'-CH3, 4'-Cl, 3',4'-(CH3)2, 4'-OCH3, 4'-Br, 4'-OCH2C6H5, and 4'-C(CH3)3, against acetylcholine-induced contraction of the guinea pig ileum. The most significant quantum chemical descriptors for this series of compounds were the net atomic charges, nucleophilic and electrophilic frontier electron density, HOMO and LUMO orbitals, and reactivity indices. While no significant correlations were found employing molecular parameters such as heat of formation, dipole moment, molecular polarizability, and so on, good correlations were obtained using the reactivity indices of HOMO and LUMO orbitals at specific atoms of the molecules. These results indicate that the spatial distribution of HOMO and LUMO orbitals over these specific atoms play an important role for an increase of biological activity.

Semi-empirical topological index: a tool for QSPR/QSAR studies

The semi-empirical topological index (I(ET)), developed to predict the chromatographic retention of a series of organic compounds, is extended to predict other properties and biological activities of aliphatic alcohols. This topological index takes into account the contribution of each individual atom type to the property considered and is able to encode information about structural features of the molecules. The efficiency of this index is verified by high quality Structure - Property and structure - Activity Relationships (QSPR/QSAR) models obtained for several representative physicochemical properties, biological activities and toxicities of aliphatic alcohols. Most of the properties investigated are well modeled (r > 0.98) employing the I(ET). Cross-validation using the more general leave-one-out method demonstrates that these models are highly statistically reliable. The proposed I(ET) index promises to be a useful descriptor in the QSPR/QSAR studies.