1,2,4-Oxadiazoles have emerged as a significant class of heterocyclic compounds in medicinal chemistry due to their diverse biological activities and versatile applications in drug discovery. Herein is reported an in-depth analysis of the structural properties, synthetic methodologies, and pharmacological significance of 1,2,4-oxadiazoles. The compound's unique five-membered ring containing three heteroatoms offers remarkable stability and tunable physicochemical properties, making it an attractive scaffold for the development of novel therapeutic agents, as confirmed by already approved drugs. The review highlights the broad spectrum of biological activities associated with 1,2,4-oxadiazoles, including antimicrobial, anti-inflammatory, anticancer, antiviral, and central nervous system related activities. These diverse effects underscore the scaffold's potential for targeting multiple disease pathways. Several studies demonstrate that structural modifications on the oxadiazole ring can significantly influence its pharmacokinetic and pharmacodynamic profiles, enabling the design of selective and potent drug candidates. Additionally, it has explored recent advances in synthetic strategies for constructing the 1,2,4-oxadiazole core, such as cyclization reactions involving amidoximes, nitrile oxides, and other precursors. Modern approaches using transition-metal catalysis, microwave-assisted synthesis, and green chemistry techniques are also discussed, emphasizing their importance in improving efficiency and scalability for pharmaceutical applications. Furthermore, the role of 1,2,4-oxadiazole as bioisostere replacement for esters and amides is highlighted, particularly in enhancing metabolic stability and modulating target selectivity. Application of computational methods, including molecular docking and QSAR modeling, have been also covered in understanding ligand-receptor interactions and guiding lead optimization. This review underscores the growing prominence of 1,2,4-oxadiazoles in modern drug design and their potential to address unmet medical needs. With continued research and innovation, these scaffolds are poised to play a pivotal role in the next generation of therapeutic agents across multiple disease areas.

Despite the fact that the variola virus is considered eradicated, the search for new small molecules with activity against orthopoxviruses remains an important task, especially in the context of recent outbreaks of monkeypox. As a result of this work, a number of amides of benzoic acids containing an adamantane fragment were obtained. Most of the compounds demonstrated activity against vaccinia virus, with a selectivity index SI = 18,214 for the leader compound 18a. The obtained derivatives also demonstrated activity against murine pox (250 ≤ SI ≤ 6071) and cowpox (125 ≤ SI ≤ 3036). A correlation was obtained between the IC₅₀ meanings and the binding energy to the assumed biological target, the p37 viral protein with R² = 0.60.

Since the emergence of AIDS, the non-nucleoside HIV-1 RT inhibitors (NNRTIs) have attracted the attention of scientists and clinicians due to their high potency and specificity combined with low toxicity. 3,4-Dihydro-2-alkoxy-6-benzyl-4-oxopyrimidines (DABOs) are a family of NNRTIs described since 1992, and the best members among S-, NH-, and N,N-DABOs showed high anti-HIV-1 potency in both cellular and enzymatic assays. During 30 years of research, the central 4-(3H)-pyrimidinone nucleus has been decorated with 2,6-dihaloaryl or cyclohexyl groups at the methylene at C6, alkyl- or (arylalkyl/aroylalkyl)thio/amino chains at C2, and hydrogen or a small alkyl group at C5. The further introduction of small (i.e., methoxy) groups at the C6 α-benzylic position furnished potency at the sub-nanomolar level against wild-type HIV-1 and at the nanomolar level against HIV-1 mutant strains. Importantly, some compounds of the DABO family exhibited preventative microbicidal activity, valuable in clinical settings where oral adherence rates are low.

Risdiplam is the first approved small-molecule therapy for spinal muscular atrophy (SMA), a severe, progressive neuromuscular disorder. In addition to its clinical significance, risdiplam is of a great interest for organic and medicinal chemistry due to its complex molecular architecture. Its structure incorporates three highly substituted heterocyclic fragments—imidazo[1,2-b]pyridazine, pyrido[1,2-a]pyrimidin-4-one, and 4,7-diazaspiro[2.5]octane—that serve as both versatile synthetic building blocks and critical pharmacophoric elements for drug design and discovery. The increasing scientific interest in risdiplam has led to numerous publications and patent applications that describe alternative synthetic methodologies. Recently, our group has also developed and introduced efficient, scalable manufacturing routes for the preparation of the target substance and the key intermediates of its synthesis. This mini-review systematically analyzes a plethora of risdiplam assembly strategies and synthetic approaches, covering developments from 2013 to the present.