Synthesis, Structural Analysis, Antimicrobial Activity and The Molecular Electrostatic Potential Surface (MEP) of 2/3/4-Chloro Benzamide-Spiro[Benzo[B]Thiophene-Dioxolane] Derivatives

Abstract

In this research, 2-amino-4,7-dihydro-5H-spiro[benzo[b]thiophene-6,2'-[1,3]dioxolane]-3-carbonitrile (ST) was synthesized using the Gewald method, starting with 1,4-dioxaspiro[4,5]decan-8-one ketone. The structures of compounds were characterized through FT-IR, 1H-NMR, and 13C-NMR spectra. The antimicrobial properties of the compounds were examined by the disk diffusion process. The compounds (N1-3) did not exhibit effectiveness against the E. Coli (ATCC) and S. Aureus (ATCC) bacteria. The molecular electrostatic potential surface (MEP) of all compounds was calculated via DFT calculations based on the optimized geometries at the B3LYP/6-31G (d,p) level of theory. Negative potential regions were located over the oxygen and nitrogen atoms, whereas positive potential regions were identified over the oxygen and sulfur atoms. Conceptually, computations of the molecular structures of the compounds were carried out using molecular modeling software, specifically GaussView 5.0 and the GAUSSIAN 09 package programs. Additionally, computations were performed for the HOMO and LUMO molecular orbitals of isolated molecules in the gas phase. Molecular electrostatic potential (MEP) surfaces were used to visualize potential interactions between receptors and ligands over the steady-state geometries of the molecules and to highlight the electrophilic and nucleophilic regions of the molecules.