Thiophenyl-chalcone derivatives: Synthesis, antioxidant activity, FMO energies and molecular parameters

Abstract

In this study, a series of thiophenyl-chalcones derivatives was synthesized and their DPPH and ABTS activities were evaluated. All thiophenyl-chalcones exhibited high antioxidant activity. Among them, 4e ((E)-5-(3-(4-(chlorosulfonyl)-3-hydroxyphenyl)-3-oxoprop-1-en-1-yl)thiophene-2-sulfonyl chloride) have higher ABTS activity (IC50 = 13.12 μM) than quercetin (IC50 = 15.49 μM), well-known as antioxidant agent and used as a standard. The structure-activity relationship results revealed that most of synthesized sulfonyl chloride derivatives (4a-e) have higher antioxidant activity than the sulphonamide derivatives (5a-c) and also 4d and 4e including hydroxyl group, exhibited the strongest antioxidant activity as expected. Additionally, the frontier molecular orbitals (FMOs) energies and molecular parameters of the synthesized molecules were calculated to support experimental results. The quantum chemical calculation results indicated that the strongest antioxidant compounds, in this study, had the lowest LUMO energies and the highest electronegativity, electron affinity and electrophilicity index.