Antioxidant activity of a series of previously described 5-amino-N-(iododi(per)fluoroalkyl)-1H-1,2,3-triazole-4-carboxamides 3a-r, their synthetic precursors 5-amino-N-allyl-1,2,3-triazole-4-carboxamides 1a-g, and their deamination products N-(3-di(per)fluoroalkyl-2-iodo-n-propyl)-1,2,3-triazole-4-carboxamides 4a-e was investigated in vitro using DPPH test and ascorbic acid as a standard reference. It was established that compounds 3a-r inhibit DPPH free radicals in moderate to high values (50.9–97.6%). The effect of substituents in the position 1 of the 1,2,3-triazole nucleus, fluoroalkyl groups and amino groups on the level of antioxidant activity was studied in detail. Reactivity and electrostatic surface potential were evaluated for the most active carboxamides 3a,g,r using the DFT method, and molecular docking was studied in the NADPH oxidase protein model.

In the present work, we report an efficient synthesis and antioxidant activity evaluation of some 4-arylimino-thiazolidin-2-ones. The structures of target substances were confirmed through ¹H and ¹³C NMR spectroscopy, mass spectrometry and elemental analysis. The antioxidant activity of the synthesized compounds was measured in vitro by the method of scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. Notably, antioxidant activity was identified for the first time among 4-arylimino-thiazolidin-2-ones.

A number of 3-aryl-5,6-dihydroimidazo[2,1-b][1,3]thiazoles were synthesized by cyclocondensation of imidazolidine-2-thione with phenacyl bromides, and their antimicrobial and antioxidant activity was evaluated. Bioscreening confirmed the moderate antibacterial activity against the reference strains of bacteria Staphylococcus aureus, Escherichia coli and Proteus vulgaris and excellent antifungal activity against Candida albicans. It was found that 3-(4-chlorophenyl)-5,6-dihydroimidazo[2,1-b]thiazole 4h (MIC = 15.625 μg/ml) has twice the antifungal effect compared to the control drug Furacilin. The study of the antioxidant activity of the synthesized compounds proved their ability to inhibit 60–97% of DPPH radicals. The best antiradical effect was found for 4-(5,6-dihydroimidazo[2,1-b]thiazol-3-yl)phenol 4e (I = 97%). A probable mechanism of its action was proposed involving the formation of a radical cation by the SET process. For the most active antioxidants 4e-g, reactivity and electrostatic surface potential were evaluated using the DFT method, and molecular docking was studied on the human peroxiredoxin 5 protein model.

The 4-bromomethyl-substituted thiazolium salts and corresponding thiazoles obtained through the condensation of 1,3-dibromoacetone with thioamide derivatives were utilised as efficient alkylating reagents for a series of thiophenols and heterylthiols. As a result, a small library of 4-thiomethyl-functionalised 1,3-thiazoles was synthesised in high yields, and their structures were characterised by ¹H, ¹³C NMR, LC-MS and IR spectra. Antioxidant activity of obtained compounds was studied in vitro using the DPPH test. The synthesised compounds showed high absorption level of DPPH radicals in the 70-98% range. For the most active derivatives 7e,m,p,t IC50 values were determined, which were in the range 191-417 µM (for ascorbic acid (reference) IC⁵⁰ value was 29 µM). Obtained radical scavenging activity screening data suggest in-depth study of the antioxidant potential for these types of heterocyclic compounds.