Theoretical Investigation of Szemaoenoid A with Abietane Skeletone

In order to analyze the structure of diterpenes having significant biological activity and predict their chemical properties, the compound of Szemaoenoid A with an abietane skeleton has been examined theoretically. Bond lengths, bond angles, dihedral angles, and 13C-NMR isotropic shielding values were calculated with both ab initio and density functional theory (DFT) methods. The correlations between theoretical and experimental results were examined by statistical analysis works. Vibrational analyses were performed at the B3LYP/cc-pVDZ level of theory. Moreover, the electronic structure (HOMO-LUMO and MEP maps) of title compound was investigated theoretically. By using the energy values of frontier molecular orbitals, the parameters of Szemaoenoid A such as frontier molecular orbital energy differences, chemical hardness and electronegativity were calculated at the B3LYP/cc-pVDZ level. It has been deduced that Szemaoenoid A shows fair chemical stability and reactivity.