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.

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.