Simulation results source for the identification of biological active compounds: synthesis, antimicrobial evaluation and SARs of three in one heterocyclic motifs

For comprehensive studies on drugs primarily in the form of biomimetic systems, electronic parameters are becoming essential tools in elucidating the structures of the investigated compounds. In this study we present the synthesis, characterization, and evaluation of biological potency of 4(a–g), 5(a–g), and 7(a–g) by conducting structure–activity relationship (SAR) studies. Further conducting density functional theory (DFT) simulation studies for entitled compounds 4(a–g), 5(a–g), and 7(a–g) allowed us to fully study the effect of the changes of electronic and molecular structures on their biological activity by demonstrating the role of frontier molecular orbitals, in particular LUMO. The electron withdrawing nitro group substituted compounds 5d and 7d have higher activity than all other active compounds. Thus, the results strongly suggest that the SARs are in good agreement with simulation studies.