Structure, energetics and properties of some molecules with potent anti-HIV activity: a theoretical study

Density functional theory (DFT; B3LYP) and Hartree-Fock (HF; 3-21G, 6-31G(d) and 6-311G(d,p)) calculations with complete geometry optimisations are carried out in the ground state on five 6-aminoquinolone derivatives, which have been proved to be highly effective in inhibiting HIV replication, to study their structures, energetics and HOMO-LUMO correlation with physiological action. The gas-phase calculations and single-point polarisable continuum model water-phase calculations show that the molecules are highly effective in inhibiting HIV replication, which is in excellent agreement with the experiment. Structural features, energies, charge densities and HOMO-LUMO correlation have been found to substantiate the experimental findings. Compound 4 (pyrazine) shows some special features in DFT calculations which are not found in HF calculations. In the present series, HF results are more reliable as expected.