The 1,3,4-thiadiazole core has attracted significant attention due to its unique electronic structure, physicochemical properties, and wide-ranging pharmacological potential. This heterocyclic scaffold exhibits a broad spectrum of biological activities, often attributed to its capacity to modulate enzyme function, interact with receptors, and disrupt key biochemical pathways in both pathogens and host cells. Additionally, 1,3,4-thiadiazoles typically display favorable pharmacokinetic properties, including high metabolic stability and appropriate lipophilicity, which enhance their drug-likeness and bioavailability. This review presents an overview of antibacterial and antifungal compounds bearing the 1,3,4-thiadiazole scaffold that have been reported over the past five years. This publication details the chemical structures of novel 1,3,4-thiadiazole derivatives and reports the results of antibacterial and antifungal activity assays conducted against a range of microbial strains. Furthermore, it provides conclusions regarding the structural features that influence the observed biological activity of the synthesized compounds. Antimicrobial activity assessments conducted against ten Gram-negative and nine Gram-positive bacterial strains revealed that 79 newly synthesized 1,3,4-thiadiazole derivatives exhibited either superior inhibitory efficacy relative to standard reference antibiotics or achieved a high level of bacterial growth suppression, defined as 90–100% inhibition. In antifungal assays, the compounds were evaluated against 25 fungal species representing 15 genera. Among the tested derivatives, 75 compounds demonstrated antifungal potency exceeding that of reference antifungal agents or produced growth inhibition within the 90–100% range. The information provided herein may serve as a valuable resource for medicinal and agricultural chemists engaged in the development of novel drug candidates and plant protection agents.

An efficient method for the synthesis of novel phenylazo-containing moieties is described. The derivatives of 5-(4-(phenyldiazenyl)phenyl)-1,3,4-oxadiazole, substituted at position 2 of the heterocyclic scaffold with alkyl groups of different chain lengths, were prepared. The titled compounds were obtained using the appropriate 4-(5-alkyl-1,3,4-oxadiazol-2-yl)anilines, which were directed to diazotization and subsequently coupled to phenol, resorcinol, and N,N-dimethylaniline. Additionally, we report a mild and effective procedure for the preparation of 4-(5-alkyl-1,3,4-oxadiazol-2-yl)anilines via the selective reduction of the corresponding 2-alkyl-5-(4-nitrophenyl)-1,3,4-oxadiazoles using sodium borohydride-tin(II) chloride dihydrate as the reducing system. The chemical structures of the prepared compounds were confirmed by ¹H- and ¹³C-NMR, IR, and UV-Vis spectroscopy.

Nitrogen-rich heterocycles constitute a family of high energy density materials (HEDMs) that have been developing intensively in recent years. A representative of this class is 1,2,4,5-tetrazine, a six-membered aromatic compound containing four nitrogen atoms in the ring. Many energetic compounds with this scaffold exhibit thermal stability, high density, and insensitivity to various stimuli, including friction, impact, and electrostatic discharge. This review presents methods for constructing 1,2,4,5-tetrazine precursors from acyclic reagents and describes their chemical modifications, leading to new energetic compounds with potential applications in the industry as explosives, propellants, or pyrotechnics. Synthetic procedures and reaction conditions are discussed, along with the detonation parameters of new nitrogen-rich tetrazine-based products, which allow estimation of their application potential.