Synthesis, characterization, and investigation of the antioxidant activity of some 1,2,4-benzothiadiazine-1,1-dioxides bearing sulfonylthioureas moieties

Abstract

A series of 1,2,4-benzothiadiazine-1,1-dioxides bearing a sulfonylthiourea moiety were synthesized, characterized, and screened for their antioxidant activity, using six antioxidant analytical assays comparatively to reference compounds, ascorbic acid and quercetin. The results indicated that several compounds demonstrated strong antioxidant activity in DPPH, ABTS, H2O2, and lipid peroxidation assays where some of them were either as active as or more active than reference compounds. However, all compounds were largely less active than references compounds in the reducing power assay. The results indicated that the thiourea moiety probably played a crucial role in the antioxidant activity of the target compounds, as a thiolate ion. The most favorable R1 groups were the hydrogen atom and methyl group, followed by phenyl and benzyl groups, whereas the most favorable R2 group was iPr, followed by the phenyl and methyl groups. The combination of benzothiadiazine ring with sulfonylthiourea moieties led to valuable new antioxidants, which could be used in the treatment or the prevention of certain diseases or in the field of cosmetics, which needs further investigations in the future.

Antioxidant properties of butylated phenol with oxadiazole and hydrazone moiety atorthoposition supported by DFT study

“… 47 The NHCS group can be regarded as a part of the thiourea system, which is known as an effective antioxidant. 48 The similarity of this case with that of phenethyl-5-bromo-pyridyl thiourea 49 further supports our conclusion. In the series of thio-oxadiazole, compound 4c (IC 50 : 43.62 ± 0.12 μg mL −1 ), with 4-bromo benzyl group next to the thio group afforded better antioxidant activity when compared to the activities observed with methyl (4a, IC 50 : >100 μg mL −1 ) or propargyl groups (4c, IC 50 : 43.62 ± 0.12 μg mL −1 ).…”