Aim. To systematize and critically analyze current scientific publications on the synthesis and biological screening of 1,2,4-triazole-3-thiol derivatives and to summarize the relationship between their structure and pharmacological activity. Special attention was paid to the prospects of using these compounds as scaffolds for the development of new biologically active substances and potential active pharmaceutical ingredients.

Materials and methods. The review included publications by domestic and foreign authors devoted to methods for the synthesis, chemical modification, and biological evaluation of 1,2,4-triazole-3-thiol derivatives. Literature retrieval was carried out in the Scopus, Web of Science, PubMed, and Google Scholar databases using Ukrainian- and English-language keywords related to 1,2,4-triazoles, triazole-3-thiols, synthesis, and biological activity. The selected sources were analyzed by systematization, comparative assessment, and generalization of data on synthetic approaches, thiol-group transformations, directions of structural modification, and the results of pharmacological screening.

Results. The analysis showed that 1,2,4-triazole-3-thiol derivatives represent an important class of heterocyclic compounds with broad possibilities for purposeful structural modification and a wide spectrum of biological effects. Their synthesis is most often based on cyclization reactions involving thiosemicarbazides, hydrazides, isothiocyanates, and related intermediates, whereas the efficiency of the process depends on solvent, temperature, catalyst, and the nature of substituents. The summarized literature indicates that these compounds may exhibit antimicrobial, antifungal, antiviral, antioxidant, anti-inflammatory, anticonvulsant, and antitumor activity, while the thiol group plays a decisive role in further S-functionalization and in shaping physicochemical and pharmacological properties.

Conclusions. 1,2,4-Triazole-3-thiol derivatives are a promising platform for medicinal chemistry because their reactivity allows targeted modification and the reported biological screening results confirm the expediency of further search for new low-toxicity and pharmacologically promising compounds in this series.