The achievements of modern domestic pharmacy clearly prove the prospects of searching for biologically active molecules among 1,2,4-triazole derivatives. The aim of our work was to predict the safest compound, select it and unambiguously prove the structure of a new promising molecule, to investigate some parameters of its toxicity. Materials and methods. X-ray diffraction analysis was performed in the laboratory of the Institute of Single Crystals of the National Academy of Sciences of Ukraine (Kharkiv). Computer methods were used to build “structure – toxicity” models and predict LD50 using already created models GUSAR, TEST. The degree of toxicity (DL50) and the approximate doses for the subacute experiment were determined by studying the acute toxicity of the test chemical and the injectable solution based on it. Determination of acute toxicity parameters by intragastric administration was performed on white rats, aged 3-4 months, body weight 200-220 g. Results. Due to the study of the toxicity of 1,2,4-triazole derivatives by non-experimental methods using GUSAR and TEST models, it was found that the test compounds could be classified as low-toxic substances. The compound is an organic salt that exists in the crystal as a solvate with one molecule of methanol and two molecules of water. When studying the structure of the crystal, it was found that the crystal is in the pinacoidal triclinic syngony. According to the results of the studies, it was found that after a single intragastric administration of the compound in doses of 1000, 3000 and 5000 mg / kg, all animals remained alive for 14 days. The basis of the biological action of chemical compounds is the violation of several biochemical processes. We found that the studied blood constants, on the background of the use of newly synthesized substance, underwent some changes. Conclusions. According to the assessment of the toxicity of the drug “VPK-434” when administered intragastrically to laboratory rats, it was found that in accordance with SOU 85.2-37-736: 2011 the test substance belongs to the IV class of toxicity (low toxicity). It was found that the average lethal dose of DL50 of the test substance by intramuscular administration to rats is 1666.66 mg / kg body weight. It was studied that some abnormalities in the hematopoietic system (increase in the number of leukocytes, including eosinophils), liver and kidney function (increased activity of transaminases, decreased serum concentrations of total protein, urea and creatinine) and changes in mineral metabolism of experimental animals groups, on the background of receiving 10 multiple doses of the study drug, was short-term, and the restoration of the functional state of the body of rats could be said as early as 4-5 days after discontinuation of the drug into their body

In this study, we’ve performed computable studies of previously synthesized 1,2,4-triazole derivatives by virtual screening due to antioxidant activity. Six enzymes responsible for regulating oxidative stress were selected as key targets. One hundred and twelve compounds were subjected to semi-flexible molecular docking, which resulted in the selection of 23 substances based on binding energy for further ADME analysis. In addition, molecular dynamics studies of complexes with the best docking scores, reference complexes and apo-proteins were described in detail here. The results of 100 ns modeling (RMSD, RMSF, SASA, Rg, PCA) indicate great stability during the formation of complexes with our two potential compounds, as well as favorable binding energy, which was determined theoretically by means of the MM/PBSA method, thereby increase the likelihood of their acting as promising inhibitors of selected enzymes.

The aim of our work is to synthesize new S-derivatives in the series of ((1,2,4-triazol-3(2H)-yl)methyl)thiopyrimidines and to study their antioxidant activity, to identify the most promising compound using molecular docking and kinetic parameters. Materials and methods. The 1H and 13C NMR spectra were recorded on a Bruker AC-500 spectrometer. LC-MS was recorded on an Agilent 1260 Infinity HPLC system equipped with a diode-array detector and proton ionization. Elemental analysis (C, H, N, S) was performed on an ELEMENTAR vario EL cube. Molecular docking was performed using the AutoDock 4.2.6 program. Free radical absorption was measured using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical assay. Results. A series of S-acyl derivatives of 4-methyl-5-((pyrimidin-2-ylthio)methyl)-4H-1,2,4-triazole-3-thiols were synthesized through alkylation and subsequent cyclization. The structure of the obtained compounds was confirmed by ¹H and ¹³C NMR spectroscopy. Antiradical activity was evaluated using the DPPH test, with compound (6) exhibiting the highest activity, surpassing ascorbic acid. Molecular docking with cytochrome c peroxidase (PDB: 2X08) confirmed strong binding interactions, highlighting the potential of these derivatives as antioxidants. Conclusions. Three compounds (1, 6, 8) exhibited higher activity than the reference drug, the natural antioxidant ascorbic acid. This high activity may be associated with the presence of pharmacophore fragments, particularly the pyrimidine skeleton and the sulfur atom linked to the 1,2,4-triazole. The IC50 for the most active compound was calculated as 4.458±1 µM, which is 27 times more effective than ascorbic acid. Molecular docking results showed that compounds 4 and 6 had the lowest binding energies, making them the most effective compounds in terms of antioxidant activity

Aim. A comprehensive study on the antimicrobial properties of new 1,2,4-triazole derivatives using the tools of in silico and in vitro studies. Materials and methods. Computer search techniques were used to find a compound with a strong antibacterial activity; in silico molecular docking (receptors for class A (PDB id: 1n9b) and class A SHV-1 (PDB id: 2zd8) beta-lactamase) and in vitro studies on 16 types of microorganisms. Then, the in silico analyzed compounds were tested in vitro for antimicrobial activity. After preparing solutions of different concentrations, the culture growth was measured on a zonal scale for detecting sizes of microbial growth inhibition zones after 24 hours (Antibiotic Zone Scale-C, model RW297, India) and a TpsDig2 software (2016, F. James Rohlf). Statistical analysis of the study results was carried out using the Statistica 13 software (StatSoft Inc., USA). Results. From the results of molecular docking, a strong binding affinity to class A enzymes has been found in compounds 2, 7, so they could be effective in the treatment of infection caused by K. pneumoniae. The ascending order of the predicted binding affinity through the calculated score for TEM and SHV enzymes was as follows: compound 4 < compound 3 < compound 1 < compound 7 < compound 2. According to our results, the studied chemical compounds 1–4, 7 inhibited the growth of many microbial species of the Enterobacteriaceae, Morganellaceae, Pseudomonadaceae, Enterococcaceae, Staphylococcaceae and Bacillaceae families. Conclusions. For the first time, studies on the complex inhibitory effect of chemical compounds 1–4, 7 were conducted using 16 bacterial strains. Evident antibacterial effects of the studied compounds have been established: compound 1 against 13, compound 2 – 9, compound 3 – 10, compound 4 – 7, compound 7 – 10 out of 16 tested polyresistant bacterial strains.

1,2,4-triazoles belong to a well-known сlass of heterocyclic compounds that are of both theoretical and practical interest. This class has been known for about 100 years, and in recent decades 1,2,4-triazoles have become one of the most attractive objects of research in the chemistry of heterocyclic compounds due to their unique properties. Recently, a considerable number of innovative synthesis methods have been developed and interesting modification of chemical variations has been proposed, for example, a three-component reaction of aryldiazonium salts with fluorinated diazoreagents and nitriles, or a combination of a fragment of 1,2,4-triazole with coumarins or naphthalene-substituted compounds in one combined molecule, and so on. As a result, scientists have obtained new derivatives of 1,2,4-triazoles with a certain number of structural features that contribute to the production of promising substances with antimicrobial, antifungal, antitubercular, antioxidant, antitumor effects, etc. These derivatives are used not only in the medical and veterinary sphere, but also in the agricultural and industrial sectors. They have found their application as dyes, corrosion inhibitors, photosensitizers, fungicides, plant growth regulators, etc. The aim of our work was to analyze and summarize the known literature data on new synthetic approaches to the production of new derivatives of 1,2,4-triazole and systematize information related to the biological properties of these compounds.

In the literature, there is insufficient information on the synthesis of compounds in a series of pyrimidine-2-thiol derivatives containing a five-membered nitrogen-containing heterocyclic fragment; at the same time, there are a sufficient number of examples, demonstrating the synthetic and biological potential for compounds of this kind. The relevance of the study “structure – acute toxicity” relationship in a number of newly synthesized derivatives of 1,2,4-triazole-3(2H)-thione with pyrimidine-2-thiol is due to the synthesis of potential low molecular weight interferon inducers and antitumor agents, the search for molecular descriptors of their structure, important for establishing “structure – acute toxicity” laws, as a system for evaluating the biological effects of compounds. Therefore, it is strategically and economically justified to conduct a study of the acute toxicity of synthesized compounds as a priority. The aim of the work is targeted synthesis of a number of S-derivatives (1,2,4-triazole-3(2H)-yl)methyl)thiopyrimidines and the establishment of the “structure – acute toxicity” relationship. Materials and methods. A modern set of physical-chemical research methods was used to study the compounds. The study of the acute toxicity of the synthesized compounds was performed on adult Danio rerio. During the experiments, the fish were kept on a diet for a test period of 96 hours, and their mortality was checked every 24, 48, 72 and 96 hours with the test compounds in each mini-aquarium containing at least 7 individuals of Danio rerio. Results. Results 1H NMR spectra confirm that the alkylation reaction occurs specifically on the sulfur atom. Thus, after analyzing LC50 data, we found that the least toxic among the studied compounds is 2-(((4-methyl-5-(octylthio)-4H-1,2,4-triazole-3-yl )methyl)thio)pyrimidine with an acute toxicity value of 49.66 mg/l. The most toxic compound is 2-(((4-methyl-5-(methylthio)-4H-1,2,4-triazole-3-yl)methyl)thio)pyrimidine with an LC50 value of 8.29 mg/l. The low toxicity of the compound 2-(((4-methyl-5-(octylthio)-4H-1,2,4-triazole-3-yl)methyl)thio)pyrimidine is most likely due to the presence of an octyl substituent, which sufficiently penetrates through biological membranes and does not have a strong toxic effect on organ systems. Furthermore, it does not accumulate but is metabolized in the cell. Conclusions. New hybrids of 1,2,4-triazole-3(2H)-yl)methyl)thiopyrimidines were obtained using the heterocyclization reaction of the intermediate carbothioamide. To reduce the indicators of acute toxicity and increase their biological activity, synthesized S-derivatives of this series were created. It was established that S-derivatives of 1,2,4-triazole-3(2H)-yl)methyl)thiopyrimidines belong to moderately toxic to low-toxic compounds according to the classification of D. R. Passino. 2-(((4-Methyl-5-(octylthio)-4H-1,2,4-triazole-3-yl)methyl)thio)pyrimidine has an acute toxicity value of 49.66 mg/l. The most toxic compound is 2-(((4-methyl-5-(methylthio)-4H-1,2,4-triazole-3-yl)methyl)thio)pyrimidine with an LC50 value of 8.29 mg/l.