Background: In the era of resistance, the design and search for new “small” molecules with a narrow spectrum of activity that target a protein or enzyme specific to a certain bacterium with high selectivity and minimal side effects remains an urgent problem of medicinal chemistry. In this regard, we developed and successfully implemented a strategy for the search for new hybrid molecules, namely, the not broadly known [2-(3-R-1H-[1,2,4]-triazol-5-yl)phenyl]amines. They can act as “building blocks” and allow for the introduction of certain structural motifs into the desired final products in order to enhance the antistaphylococcal effect. Methods: The “one-pot” synthesis of the latter is based on the conversion of substituted 4-hydrazinoquinazolines or substituted 2-aminobenzonitriles and carboxylic acid derivatives to the target products. The possible molecular mechanism of the synthesized compounds (DNA gyrase inhibitors) was investigated and discussed using molecular docking, and their further study for antistaphylococcal activity was substantiated. Results: A significant part of the obtained compounds showed high antibacterial activity against Staphylococcus aureus (MIC: 10.1–62.4 µM) and 5-bromo-2-(3-(furan-3-yl)-1H-1,2,4-triazol-5-yl)aniline and 5-fluoro-2-(3-(thiophen-3-yl)-1H-1,2,4-triazol-5-yl)aniline, with MICs of 5.2 and 6.1 µM, respectively, approaching the strength of the effect of the reference drug, “Ciprofloxacin” (MIC: 4.7 µM). The conducted SAR and ADME analyses confirm the prospects of the further structural modification of these compounds. The obtained [2-(3-R-1H-[1,2,4]-triazol-5-yl)phenyl]amines reveal significant antimicrobial activity and deserve further structural modification and detailed study as effective antistaphylococcal agents. The SAR analysis revealed that the presence of a cycloalkyl or electron-rich heterocyclic fragment in the third position of the triazole ring was essential for the antibacterial activity of the obtained compounds. At the same time, the introduction of a methyl group into the aniline moiety led to an enhancement of activity. The introduction of halogen into the aniline fragment has an ambiguous effect on the level of antistaphylococcal activity and depends on the nature of the substituent in the third position. Conclusions: Obtained [2-(3-R-1H-[1,2,4]-triazol-5-yl)phenyl]amines reveal significant antistaphylococcal activity and deserve for further detailed study as effective antibacterial agents.

Agents with antifungal activity play a vital role as therapeutics in health care, as do fungicides in agriculture. Effectiveness, toxicological profile, and eco-friendliness are among the properties used to select suitable substances. Furthermore, a steady supply of new agents with different modes of action is required to counter the well-known potential of human and phyto-pathogenic fungi to develop resistance against established antifungals. Here, we use an in vitro growth assay to investigate the activity of the calcineurin inhibitor tacrolimus in combination with the commercial fungicides cyproconazole and hymexazol, as well as with two earlier reported novel {2-(3-R-1H-1,2,4-triazol-5-yl)phenyl}amines, against the fungi Aspergillus niger, Colletotrichum higginsianum, Fusarium oxysporum and the oomycete Phytophthora infestans, which are notoriously harmful in agriculture. When tacrolimus was added in a concentration range from 0.25 to 25 mg/L to the tested antifungals (at a fixed concentration of 25 or 50 mg/L), the inhibitory activities were distinctly enhanced. Molecular docking calculations revealed triazole derivative 5, (2-(3-adamantan-1-yl)-1H-1,2,4-triazol-5-yl)-4-chloroaniline), as a potent inhibitor of chitin deacetylases (CDA) of Aspergillus nidulans and A. niger (AnCDA and AngCDA, respectively), which was stronger than the previously reported polyoxorin D, J075-4187, and chitotriose. The results are discussed in the context of potential synergism and molecular mode of action.

A new class of spiro[1,2,4]triazolo[1,5-c]quinazoline derivatives is presented as promising modulators of diacylglycerol kinase α (DGK-α), a target implicated in cancer, neurological disorders, and immune dysfunction. Through structure-based computational design using the CB-Dock2 platform with human DGK-α (PDB ID: 6IIE), 40 novel compounds were systematically evaluated along with established inhibitors (ritanserin, R59022, R59949, BMS502, and (5Z,2E)-CU-3) across five distinct binding pockets. Several compounds demonstrated binding profiles at the level of or surpassing the reference compounds. The physicochemical analysis revealed balanced drug-like properties with favorable molecular weights (252–412 g/mol) and appropriate three-dimensionality. The toxicological assessment indicated reassuring safety profiles with predicted LD₅₀ values of 1000–2000 mg/kg and minimal hepatotoxicity, carcinogenicity, and mutagenicity potential. Notably, compound 33 (adamantyl-substituted) emerged as exceptionally promising, exhibiting strong binding affinity, moderate solubility, and selective CYP inhibition patterns that minimize drug–drug interaction risks. Detailed molecular interaction mapping identified critical binding determinants, including strategic hydrogen bonding with TRP151, GLU166, and ARG126. The multidimensional evaluation identified compounds 13, 18, 33, and 40 as particularly promising candidates that balance potent target engagement with favorable pharmaceutical profiles, establishing this scaffold as a valuable platform for developing next-generation therapeutics targeting DGK-α -mediated signaling pathways.

Background: Designing novel biologically active compounds with anti-inflammatory properties based on condensed quinazolines is a significant area of interest in modern medicinal chemistry. In the present study, we describe the development of promising new bioactive molecules through the bioisosteric replacement of a carbon atom with a sulfur atom in anti-inflammatory agents, specifically 3-methyl-2-oxo-2H-[1,2,4]triazino[2,3-c]quinazolin-6-yl)butanoate. Methods: Design and synthetic studies have led to the series of previously unknown substituted 2-[((3-R-2-oxo-2H-[1,2,4]triazino[2,3-c]quinazolin-6-yl)methyl)thio]carboxylic acids and their esters. These compounds were synthesized by reacting 6-chloroalkyl-3-R-2H-[1,2,4]triazino[2,3-c]quinazolin-2-ones with sulfanylalkyl carboxylic acids and their functional derivatives. The purity and structure of the obtained compounds were confirmed using a set of physicochemical methods, including elemental analysis, HPLC-MS, and ¹H NMR spectroscopy. Molecular modeling, predicted toxicity, drug-likeness, and pharmacokinetics data were used to select compounds for evaluation of their effects on acute aseptic inflammation (carrageenan-induced paw edema test) and on markers of the inflammatory process. Results: The compound 2-((1-(3-methyl-2-oxo-2H-[1,2,4]triazino[2,3-c]quinazolin-6-yl)ethyl)thio)acetic acid (compound 2e) was identified as the most active anti-inflammatory agent (AA = 53.41%), demonstrating significant inhibition of both paw edema development and the generation of pro-inflammatory cytokines and mediators. Conclusions: Results from docking studies and analysis of “structure-affinity” correlations revealed that these compounds are promising candidates for further modification and detailed investigation of their anti-inflammatory activity

This study unveils a new class of spiro[1,2,4]triazolo[1,5-c]quinazoline derivatives as promising diacylglycerol kinase α (DGKα) modulators, a target implicated in cancer, neurological disorders, and immune dysfunction. Through structure-based computational design using the CB-Dock2 platform with human DGKα EF-hand domains (PDB ID: 6IIE), 40 novel compounds were systematically evaluated along established inhibitors (ritanserin, R59022, R59949, BMS502, and (5Z,2E)-CU-3) across five distinct binding pockets. Several compounds demonstrated remarkable binding profiles at the level or surpassing reference compounds. The physicochemical analysis revealed balanced drug-like properties with favorable molecular weights (252-412 g/mol) and appropriate three-dimensionality. Toxicological assessment indicated reassuring safety profiles with predicted LD50 values of 1000-2000 mg/kg and minimal hepatotoxicity, carcinogenicity, and mutagenicity potential. Notably, compound 33 (adamantyl-substituted) emerged as exceptionally promising, exhibiting strong binding affinity, moderate solubility, and selective CYP inhibition patterns that minimize drug-drug interaction risks. Detailed molecular interaction mapping identified critical binding determinants, including strategic hydrogen bonding with TRP151, GLU166, and ARG126. The multidimensional evaluation identified compounds 13, 18, 33, and 40 as particularly promising candidates that balance potent target engagement with favorable pharmaceutical profiles, establishing this scaffold as a valuable platform for developing next-generation therapeutics targeting DGKα-mediated signaling pathways.