Theoretical study of the structural features and antioxidant potential of 4-thiazolidinones

Abstract

4-Thiazolidinone compounds have been reported to display good antioxidant activity. In the present work, the five-membered ring has been studied extensively at the DFT-B3LYP/6-311(++)G(d,p) level of theory. The geometrical features of the ring have been explored in the gas and solvent phase. Various molecular descriptor characteristics of the antioxidant compound have been calculated and compared with the reference antioxidant, trolox. Three probable antioxidant mechanisms, hydrogen atom transfer (HAT), single electron transfer (SET), and sequential proton loss electron transfer (SPLET), have been explored, both in the gas and solvent phase. It has been found that the ring exerts its antioxidant activity predominantly following the HAT pathway, both in the gas and solvent phase. In order to determine the feasibility of the overall redox reaction, the standard redox potentials have been calculated for the ring and free radicals. Furthermore, the effect of substitution on the antioxidant parameters of the ring has been explored. Results indicate that substitution at the C2 position is advantageous over that at C5 in improving such parameters. Along with this, the effect of substitution at the C2 position on the proton affinity of the C5 position has also been investigated in detail.