Synthesis, Biological Activity of 5-Substituted-2,4-Dihydro-1,2,4-Triazole-3-Thiones and Their Derivatives

Derivatives of 1,2,4-triazole-3-thione exhibit a variety of biological activities, includ-ing: antimicrobial (e.g., compounds 31d-k, 32d, 36f), antitumor (e.g., 71, 77a-c, 82g, 94h), anti-inflammatory, analgesic (100a, 102, 105), antidiabetic and antioxidant (104, 138) activity. These compounds can be efficiently synthesized by classical methods (e.g., cyclization of thiosemicarbazides) and/or modern "green" approaches, which al-low obtaining target compounds in high yields (up to 96%). The presence of elec-tron-donating groups (e.g., -OH, -OCH₃) enhances antimicrobial and antitumor activi-ty. Substituents in the aromatic ring (e.g. NO₂, Cl) affect the ability to bind to biological targets such as DNA or enzymes. 1,2,4-triazole-3-thiones can also be used as fungicides and herbicides (e.g. 131), demonstrating high efficiency against phytopathogens. Thus, 1,2,4-triazole-3-thione derivatives are multifunctional compounds with high potential for the development of new drugs and agrochemicals. Their further study and modifi-cation can lead to the creation of more effective and safer drugs.