Ethyl 4-methyl-2-(phenylamino)thiophene-3-carboxylate: One-pot synthesis, structural characterization, computational studies, and antitumor activity

Abstract

Ethyl 4-methyl-2-(phenylamino)thiophene-3-carboxylate (8) was synthesized via a one-pot three-component reaction of ethyl 3-oxobutanoate, PhNCS, and 1-chloropropan-2-one in NaOEt. This process offers several advantages over previously reported synthetic method, including high yield, less reaction time and availability of the starting materials. Spectral data and X-ray analysis were used to elucidate the structure. Its structure is stabilized by a strong intramolecular N–H…O hydrogen bond. Hirshfeld analysis indicated the most dominant non-covalent interactions are C…H (26.3 %) and H…H (53.9 %), where the C11…H2 (2.760 Å) and C7…C7 (3.314 Å) contacts are the shortest contacts. In addition, DFT-based computational studies were performed to assess the electronic structure and local reactivity of thiophene 8. HOMO–LUMO energy gaps, MEP surface mapping, Mulliken charge distribution, and Fukui function analyses were used to identify the key electrophilic and nucleophilic centers within the molecules. Antitumor activity of thiophene 8 was assessed against HepG2 (liver cancer), MCF-7 (breast cancer), and HCT116 (colorectal cancer) by means of the sulforhodamine B (SRB) assay. The compound exhibited promising anticancer activity, showing its highest potency against HepG2 (IC50 =40.1 ± 1.3 μg/mL) compared to MCF-7 (76.3 ± 2.5) and HCT-116 (92.9 ± 2.02 μg/mL) cell lines.