Synthesis, mechanistic insights, and anticancer evaluation of novel 2-aroylbenzo[b]thiophen-3-ols: A DFT and Hirshfeld surface analysis

Abstract

A simple one-pot reaction was employed for the synthesis of 2-aroylbenzo[b]thiophene derivatives by reacting 2-mercaptobenzoic acid with substituted bromomethyl aryl ketones in the presence of triethylamine and DMF in significant yield and purity. The structure of the product was elucidated through spectroscopic data and confirmed through single crystal X-ray diffraction data. The benzo[b]thiophene ring was found to be nearly coplanar with the adjacent carbonyl group and conformationally stabilized by intramolecular hydrogen bonding. The key intramolecular cyclization takes place via an in-situ generated enol, which is most likely formed and reacts at the carboxylic group mediated by the conjugate acid, triethylammonium bromide. Density functional theory (DFT) was employed to investigate the energy profile of the reaction at the B3LYP/6–31G(d,p) level. Finally, all the synthesized 2-aroylbenzo[b]thiophene-3-ols were screened in vitro against HCT116 (colorectal) and MCF-7 (breast) cancer cell lines at 25 μM and 50 μM treatments, indicating the antiproliferative potential of several derivatives.