The chemical structures of 11 tested compounds (1-11) and 39 structurally modified compounds (series 1-11) were drawn using the GaussView software (Dennington et al., 2003). Optimization was performed to obtain the low-energy conformers for further calculation of molecular descriptor values. The compounds were geometrically optimized using Gaussian 09 (Frisch et al., 2009) at the semi-empirical Austin Model 1 (AM1) level, followed by density functional theory (DFT) calculation using Becke's three-parameter hybrid method with the Lee-Yang-Parr correlation functional (B3LYP) together with the 6-31g(d) level. A set of 13 quantum chemical descriptors, i.e., mean absolute atomic charge (Qm), total energy (Etotal), total dipole moment (μ), highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), energy difference of HOMO and LUMO (HOMO-LUMOGap), electron affinity (EA), ionization potential (IP), Mulliken electronegativity (χ), hardness (η), softness (S), electrophilic index (ωi) and electrophilicity (ω), was extracted using a script developed in-house. The optimized structures were further calculated to obtain an additional set of 3,224 molecular descriptors using Dragon software version 5.5 (Talete, 2007). The molecular descriptors obtained from the Dragon software included 22 classes, i.e., Constitutional descriptors, Topological descriptors, Walk and path counts, Connectivity indices, Information indices, 2D autocorrelation, Edge adjacency indices, Burden eigenvalues, Topological charge indices, Eigenvalue-based indices, Randic molecular profiles, Geometrical descriptors, RDF descriptors, 3D-MoRSE descriptors, WHIM descriptors, GETAWAY descriptors, Functional group counts, Atom-centered fragments, Charge descriptors, Molecular properties, 2D binary fingerprints and 2D frequency fingerprints.