Thiazolo[3,2-a]pyrimidines are structural analogues of biogenic purine bases, thus may be considered as potential purine antagonists. The synthesis of these heterocyclic systems attracts significant attention from researchers in the field of organic and medicinal chemistry due to their wide range of biological activities, e.g. anti-inflammatory, antimicrobial, antioxidant, antiviral, and anticancer. The high bioactivity of thiazolo[3,2-a]pyrimidine derivatives stimulates the development of fundamentally new synthesis options, which include modern catalytic, microwave and ultrasonic methods for activating cycloaddition reactions, and the improvement of already known methods. This, in turn, became a strong basis for summarizing and systematizing the existing array of literature sources from 2000 to 2024 relating to the methods of obtaining and biomedical profile of thiazolo[3,2-a]pyrimidines and their hydrogenated analogues.

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.

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.

Here derivatives of imidazo[2,1-b][1,3]thiazines are attractive objects for organic and medicinal chemists. In the present work chemoselective conditions for oxidation of the sulfur atom in the 6-(2-pyridinyloxy)substituted (benzo)imidazo[2,1-b][1,3]thiazines to the corresponding sulfoxides were proposed and their synthesis was performed. Synthesized sulfoxides exist in the diastereomeric mixture and individual diastereomers 2a-e and 3a-e were obtained using a chromatographic technique. The structure of compounds 2a-e and 3a-e were characterized using ¹H, ¹³C NMR, LC-MS spectra, and X-ray analysis for derivative 2b. The anti-inflammatory activity screening in vivo was performed using the carrageenan model of inflammatory paw edema in white rats for all the diastereomeric mixtures and individual diastereomers. Diastereomer 2c possessed an anti-inflammatory effect with an inflammation inhibition index of 46.1% which was equal to the activity of the reference drug diclofenac sodium.