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5-R-1,2,4-triazole-3-thiones and their derivatives are easy to obtain; they have low toxicity and a broad spectrum of the biological activity. It makes this class of heterocyclic compounds promising for creating potential drugs.

Aim. To develop the preparative methods for the synthesis of 5-aryl-1,2-dihydro-3H-1,2,4-triazole-3-thiones and study their reactivity in the alkylation reaction.

Results and discussion. New 5-aryl-1,2-dihydro-3H-1,2,4-triazole-3-thiones were synthesized. The latter were used for the synthesis of 3-aryl-5-(alkylthio)-4H-1,2,4-triazoles.

Experimental part. Using a series of four successive reactions based on the substituted benzoic acids new 5-aryl-1,2-dihydro-3H-1,2,4-triazole-3-thiones were synthesized. Alkylation of the thiones allowed obtaining a series of S-alkyl derivatives. The structure of the compounds synthesized was confirmed by elemental analysis, IR and ¹H NMR spectroscopy, and their individuality was determined by high-performance liquid chromatography.

Conclusions. The preparative methods have been developed, and new 5-aryl-1,2-dihydro-3H-1,2,4-triazole-3-thiones have been synthesized. Alkylation of the latter made it possible to obtain a series of 3-aryl-5-(alkylthio)-4H-1,2,4-triazoles with an alkylthio fragment of different length.

Aim. To demonstrate the advantages of large-scale virtual libraries generated using chemical protocols previously validated in primary steps of the drug discovery process.
Results and discussion. Two validated parallel chemistry protocols reported earlier were used to create the chemical space. It was then sampled based on diversity metric, and the sample was subjected to the virtual screening on BRD4 target. Hits of virtual screening were synthesized and tested in the thermal shift assay.
Experimental part. The chemical space was generated using commercially available building blocks and synthetic protocols suitable for parallel chemistry and previously reported. After narrowing it down, using MedChem filters, the resulting sub-space was clustered based on diversity metrics. Centroids of the clusters were put to the virtual screening against the BRD4 active center. 29 Hits from the docking were synthesized and subjected to the thermal shift assay with BRD4, and 2 compounds showed noticeable dTm.
Conclusions. A combination of cheminformatics and molecular docking was applied to find novel potential binders for BRD4 from a large chemical space. The selected set of predicted molecules was synthesized with a 72 % success rate and tested in a thermal shift assay to reveal a 6 % hit rate. The selection can be performed iteratively to fast support of the drug discovery.

Aim. To synthesize 4-amino-5-(quinolin-2-yl)-4H-1,2,4-triazole-3-thiol and study its reactivity in the reaction
with aldehydes.
Results and discussion. 4-Amino-5-(quinolin-2-yl)-4H-1,2,4-triazole-3-thiol was synthesized, and a number of 4-(ethyl, aryl)idenamino derivatives were obtained on its basis.
Experimental part. Using a series of four successive reactions based on quinoline-2-carboxylic acid, 4-amino-5-(quinolin-2-yl)-4H-1,2,4-triazole-3-thiol was synthesized; its interaction with aldehydes allowed to obtain a number of 4-(ethyl, aryl)idenamino derivatives. The structure of all compounds synthesized was confrmed by IR and ¹H NMR spectroscopy, as well as by elemental analysis, and their purity by thin layer chromatography.
Conclusions. 4-Amino-5-(quinolin-2-yl)-4H-1,2,4-triazole-3-thiol has been synthesized. It has been found that its interaction with aldehydes leads to the formation of new 4-((ethyl, aryl)idenamino)-5-(quinolin-2-yl)-4H-1,2,4-triazole-3-thiols.
Key words: 5-(quinolin-2-yl)-1,2,4-triazole-3-thiol; 4-arylidenamino derivatives; quinaldic acid; biological
activity

A series of 6-aryl[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole derivatives has been synthesized. Their anti-inflammatory activity has been studied in vivo in a carrageenan model of the paw inflammatory edema in rats. 3-(2-Fluorophenyl)-6-phenyl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole (3c) and 3-(2-fluorophenyl)-6-(4-methoxy-phenyl)[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole (3d) have been identified as hit compounds with the anti-exudative activity. The crucial role of the fluorine atom in the anti-inflammatory activity has been determined, which value considerably correlates with the calculated values of lipophilicity and solubility.

During the last decade, national and foreign scientists have been constantly examining an example of studying the physicochemical and biological properties of nitrogen containing heterocycles, particularly with the nucleus of 1,2,4-triazole. The main advantage of such substances is to exhibit low levels of acute toxicity with a wide spectrum of pharmacological activity. To date, a large number of medicines on the basis of 1,2,4-triazole has been created, namely fluconazole, voriconazole, anastrozole, itraconazole, and letrozole. Therefore, the creation of new molecules based on 1,2,4-triazole and the search for new biologically active compounds among them is an urgent task of modern synthetic and pharmaceutical chemistry.

Aim. To study some aspects of 5-phenethyl-1H-1,2,4-triazole-3-amine reactivity and investigate the physicochemical properties of synthesized compounds.

Results and discussion. A series of 1-alkyl(aryl)-N-(5-phenethyl-1H-1,2,4-triazolе-3-yl)methanimines has been synthesized and the reaction of their reduction has been studied. The structure and purity of the synthesized compounds have been confirmed by the complex of modern instrumental methods of analysis – elemental analysis, IR, ¹H NMR spectroscopy, LC-MS.

Experimental part. The reaction of 5-phenethyl-1H-1,2,4-triazole-3-amine with aldehydes at the ambient temperature in acetic acid medium gave 1-alkyl(aryl)-N-(5-phenethyl-1H-1,2,4-triazolе-3-yl)methanimines. At the next stage, the selective reduction of the exocyclic C=N-group of 1-alkyl(aryl)-N-(5-phenethyl-1H-1,2,4-triazolе-3-yl)methanimines by the action of sodium borohydride in the dimethylformamide was carried out.

Conclusions. 13 new 1,2,4-triazole derivatives, namely 1-alkyl(aryl)-N-(5-phenethyl-1H-1,2,4-triazolе-3-yl)methanimines and arylmethyl-(5-phenethyl-1H-1,2,4-triazolе-3-yl)amines, have been obtained. The both structure and purity of the obtained substances have been confirmed by the complex of modern instrumental methods of analysis.

Received: 12.08.2019
Revised: 18.09.2019
Received after correction: 27.12.2019
Revised: 25.04.2020
Accepted: 29.05.2020

Aim. To conduct the synthesis and confirm the structure of 3-methyl-6-R-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole derivatives as potential biologically active compounds.

Results and discussion. It has been shown that the heterocyclization reaction of 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol with carboxylic acids in the excess of phosphorus oxychloride yields 3-methyl-6-R-[1,2,4]-triazolo[3,4-b][1,3,4]thiadiazoles.

Experimental part. The reaction of 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol with the corresponding carboxylic acids was carried out in the excess of phosphorus oxychloride. The mixture was heated for 5 h with subsequent cooling and neutralization to pH 7 using ammonia solution. ¹H NMR spectra of the compounds synthesized were recorded on a Varian Mercury VX-200 spectrometer operating at a frequency of 200 MHz, in DMSO-d₆, using tetramethylsilane (TMS) as an internal standard. Melting points were measured using a MPA100 device. The elemental analysis was performed on a Elementar Vario EL Cube elemental analyzer. Agilent 1260 Infinity HPLC System equipped with Agilent 6120 mass spectrometer were used for registering LC-MS data.

Received: 18.02.2020
Revised: 29.04.2020
Accepted: 29.05.2020

Aim. To study pharmacokinetic parameters of the potential active pharmaceutical ingredient (API) morpholinium 2-((4-(2-methoxyphenyl)-5-(pyridin-4-yl)-4H-1,2,4-triazol-3-yl)thio)acetate in the blood plasma of rats when administered intraperitoneally.

Results and discussion. The HPLC-MS method of determination of morpholinium 2-((4-(2-methoxy)-5-(pyridin-4-yl)-4H-1,2,4-triazol-3-yl)thio)acetate in the blood plasma of non-linear rats has been adopted to study of pharmacokinetic parameters of the compound. It has been proven that high levels of API extraction from the blood plasma when using methanol for protein precipitation were observed. The measurement of the concentration of the drug substance studied in the blood plasma at different time intervals after injection allowed us to plot the pharmacokinetic curve and calculate the pharmacokinetic parameters.

Experimental part. The Agilent 1260 Infinity liquid chromatography system consisted of a degasser, binary pump, autosampler, column thermostat, diode-matrix detector, single-quadrupole mass spectrometric detector (Agilent 6120). The pharmacokinetic study was performed in sexually mature white nonlinear rats of two sexes. The active pharmaceutical ingredient morpholinium 2-((4-(2-methoxy)-5-(pyridin-4-yl)-4H-1,2,4-triazol-3-yl)thio)acetate, was administered in the isotonic solution intraperitoneally in the dose of 50 mg/kg.

Conclusions. The pharmacokinetic curve has been plotted, and the pharmacokinetic parameters of morpholinium 2-((4-(2-methoxy)-5-(pyridin-4-yl)-4H-1,2,4-triazol-3-yl)thio)acetate in the blood plasma when administered intraperitoneally have been calculated.

Received: 30.06.2020

Revised: 08.08.2020

Accepted: 27.08.2020

Aim. To determine the fragmentation pathways of eight 1,2,4-triazole-3-thiones, which are intermediate products in the synthesis of active pharmaceutical ingredients of potential and registered pharmaceutical formulations.

Results and discussion. HPLC-MS analysis of eight 1,2,4-triazole-3-thiones, which are intermediate products in the synthesis of salts of 1,2,4-triazolylthioacetate acids, has been carried out; the mass spectra of the compounds to be analyzed have been registered in ESI-mode with different fragmentor voltage (0, 100, 200 V). The fragmentation pathways and patterns of ion decay for compounds to be analyzed have been proposed.

Experimental part. Agilent 1260 Infinity HPLC System with Agilent 6120 mass spectrometer were used. HPLC-MS conditions: column – 4,6 × 30 mm, reversible phase Zorbax SB C18, 1.8 μm, 40 ^oC; mobile phase – 0.1 % HCOOH in H₂O and 0.1 % HCOOH in СH₃CN in isocratic mode (50:50, v/v); the flow rate – 0.4 mL/min; ion source – API-ES; positive polarity; drying gas – nitrogen (rate – 10 L/min); the capillary voltage – 4000 V; scanning in the range of m/z 100 – 1000.

Conclusions. For the first time it has been interpreted the mass spectra of 1,2,4-triazole-3-thiones series, the intermediate compounds in the synthesis of active pharmaceutical ingredients of pharmaceutical formulations. The fragmentation pathways and patterns of eight 1,2,4-triazole-3-thiones have been shown.

Received: 06.09.2019
Revised: 20.01.2020
Accepted: 27.02.2020

Aim. To study the dependence of the retention of morpholinium 2-((4-(2-methoxyphenyl)-5-(pyridinyl)-4H-1,2,4-triazol-3-yl)thio)acetate and its technological impurities on temperature, as well as determine the thermodynamic characteristics of the transfer from the mobile phase to the stationary phase using hydrophilic chromatography.

Results and discussion. The retention factors depending on the absolute temperature were determined in order to study the thermodynamic parameters of the transfer of analytes from the mobile phase to the stationary one. Based on the van ‘t Hoff equation a curve of lnk dependence on 1/T was constructed. The least squares method was used to create the linear dependence equation. The standard molar enthalpies, as well as the conditional standard entropy of the transfer from the mobile to the stationary phase of the test substances, namely morpholinium 2-((4-(2-methoxyphenyl)-5-(pyridinyl)-4H-1,2,4-triazol-3-yl)thio)acetate, pyridine-4-carbohydrazide, 2-isonicotinoyl-N-(2-methoxyphenyl)hydrazine-1-carbothioamide and 4-(2-methoxyphenyl)-5-(pyridinyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione were calculated. The negative enthalpy of the transfer for all substances shows that the substances are adsorbed on the surface of a silica gel with the release of heat. Therefore, the process of transition of a substance from the mobile phase to the stationary one prevails over the reverse process.

Experimental part. The Agilent 1260 Infinity liquid chromatography system consisting of a degasser, binary pump, autosampler, column thermostat, diode array detector was used for our experiments.

Conclusions. It has been found that all the compounds studied have a negative value of the transfer enthalpy, and it indicates the predominant transition of these analytes from the mobile phase to the stationary one. Conditional standard entropies of the analyte transfer from the mobile phase to the stationary phase have been calculated, and it has been proven that they significantly affect the transfer process.

Received: 11.08.2020
Revised: 25.10.2020
Accepted: 14.11.2020

Aim. To synthesize and study the antitumor activity of 3-R-6-(4-methoxyphenyl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine derivatives.

Results and discussion. To determine the antitumor activity of 3-R-6-(4-methoxyphenyl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine hydrobromides, the in vitro study was conducted on 60 lines of cancer cells (leukemia, non-small cell lung cancer, colon cancer, CNS cancer, melanoma, ovarian cancer, renal cancer, prostate cancer and breast cancer) according to the standard procedure of the mitotic activity assessment of new potential bioactive compounds by the fluorescent coloring method (sulforhodamine B as a dye). It was performed in the US National Сancer Institute within the Development Therapeutic Program. It has been found that derivatives of 3-R-6-(4-methoxyphenyl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine exhibit the antineoplastic activity against a wide range of cancer cells lines and are promising core structures for creating new effective anticancer agents.

Experimental part. 3-R-6-(4-methoxyphenyl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine hydrobromides were synthesized by the interaction of 4-amino-5-R-4H-1,2,4-triazole-3-thiols with 4-methoxyphenacyl bromide in ethyl acetate. The ¹Н NMR spectra were recorded on a Bruker VXR-300 spectrometer (Germany) with the working frequency of 299.945 MHz.

Conclusions. A series of 3-R-6-(4-methoxyphenyl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine hydrobromides has been synthesized. The anticancer activity of the compounds obtained has been studied in the National Cancer Institute on 60 lines of tumor cells. Compounds that exhibit high levels of the antitumor activity have been found. It has been shown that the replacement of 3-H in compound 3a with ethyl or pentyl radicals leads to increase in the antitumor activity against MDA-MB-468 breast cancer cells.

Received: 04.02.2020
Revised: 03.09.2020
Accepted: 17.09.2020

Aim. To synthesize, prove the structure and study the analgesic and anti-inflammatory activities of 3-(het)-aryl-2-(6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[4,3-a]azepin-3-yl)acrylonitrile derivatives.

Results and discussion. Condensation of 2-methoxy-3,4,5,6-tetrahydro-7H-azepine with cyanoacetic acid hydrazide leads to formation of 2-(6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[4,3-a]azepin-3-yl)acetonitrile. The latter readily reacts with the corresponding (het)arenecarbaldehydes in refluxing ethanol in the presence of catalytic amount of piperidine yielding a series of new 3-(het)aryl-2-(6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[4,3-a]azepin-3-yl)acrylonitrile derivatives. Further functionalization of 3-(4-hydroxy-3-R-phenyl)-2-(6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[4,3-a]azepin-3-yl)acrylonitriles has been done by modification of the OH group. One of the compounds synthesized, namely 3-(4-hydroxyphenyl)-2-(6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[4,3-a]azepin-3-yl)acrylonitrile, exhibits a high level of the analgesic activity on the “hot plate” model, and a similar level of the activity on the model of “acetic acid-induced writhings” as compared to ketorolac. The results obtained indicate the pronounced antinociceptive activity for the test compound.

Experimental part. ¹H NMR spectra of the compounds synthesized were recorded on a Bruker VXR-300 spectrometer (Germany) operating at a frequency of 299.945 MHz, in DMSO-d₆, using tetramethylsilane (TMS) as an internal standard. Melting points were measured using a RNMK 05 device (VEB Analytik,Dresden). The elemental analysis was performed on a EuroEA 3000 elemental analyzer. The analgesic and anti-inflammatory activities of 3-(4-hydroxyphenyl)-2-(6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[4,3-a]azepin-3-yl)acrylonitrile were determined using models of “carrageenan induced paw edema”, ”hot plate” and “acetic acid-induced writhings”, and compared to the reference drug ketorolac.

Conclusions. A series of new 3-(het)aryl-2-(6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[4,3-a]azepin-3-yl)acrylonitrile derivatives can be easily synthesized by the interaction of 2-(6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[4,3-a]azepin-3-yl)acetonitrile with (het)arenecarbaldehydes. The hydroxy group in 3-(4-hydroxy-3-R-phenyl)-2-(6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[4,3-a]azepin-3-yl)acrylonitriles can be modified to obtain phenyl esters of aliphatic and aromatic carboxylic acids. The high level of the analgesic activity for 3-(4-hydroxyphenyl)-2-(6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[4,3-a]azepin-3-yl)acrylonitrile has been determined.

Received: 30.01.2020
Revised: 17.05.2020
Accepted: 29.05.2020

It is known that carboxyl groups bonded to aryl or hetaryl moieties play a role of the “pharmacophore” fragment in most NSAID molecules. It should be mentioned that the carboxyl group may cause the appearance of toxic effects and is characterized by unsatisfactory pharmacokinetic properties. The structural modification of the carboxyl group, including its bioisosteric replacement, is among the most widely used approaches in medicinal chemistry to improve pharmacodynamic, pharmacokinetic and technological characteristics.

Aim. To develop the synthetic procedures for functional derivatives of 3-R-2,8-dioxo-7,8-dihydro-2Н-pyrrolo[1,2-а][1,2,4]triazino[2,3-с]quinazoline-5а(6Н)-carboxylic(-propanoic) acids, study the effect of the carboxyl group chemical modification on the LOX-inhibiting and antiradical activity as a possible mechanism of the pharmacological activity.

Results and discussion. The synthesis of esters of 3-(2,8-dioxo-3-R¹-7,8-dihydro-2H-pyrrolo[1,2-a][1,2,4]triazino[2,3-c]quinazolin-5a(6H)-yl)carboxylic(propanoic) acids was conducted by esterification of the corresponding acids and tandem heterocyclization of 2-(6-R¹-2,5-dihydro-5-оxo-1,2,4-triazino-3-yl)anilines with diethyl 4-oxoheptanedioate. The synthesis of amides was conducted by aminolysis of N-acylimidazolides generated in situ. The antiradical and LOX-inhibiting activities of the compounds obtained were studied as possible mechanisms of the anti-inflammatory activity. The series of the compounds revealed the LOX-inhibiting activity that was comparable with the effect of the reference compound – nordihydroguaiaretic acid.

Experimental part. The synthetic procedures were conducted according to the commonly used methods. The purity and the structure of the compounds obtained were proven by modern physicochemical methods (¹H and ¹³C NMR-spectroscopy, LC-MS-spectrometry). The antiradical activity was measured by the ability to scavenge a DPPH-radical. The study of the LOX-inhibiting activity was performed using soybean LOX as an enzyme and linolenic acid as a substrate.

Conclusions. The methods for the synthesis of esters and amides of 2,8-dioxo-3-R¹-7,8-dihydro-2H-pyrrolo[1,2-a][1,2,4]triazino[2,3-c]quinazolin-5a(6H)-carboxilic(propanoic) acids have been developed. The abovementioned transformations were conducted by alcoholysis of generated in situ acyl halides and aminolysis of N-acylimidazolides, respectively. The more efficient approach for the synthesis of the target esters via condensation of 2-(6-R¹-2,5-dihydro-5-oxo-1,2,4-triazino-3-yl)anilines with diethyl 4-oxoheptanedioate has been proposed. It has been found that the highest radical scavenging and LOX-inhibiting activities are characteristic for hetarylpropanoic acids that contain electron withdrawing substituents in position 3, as well as fluorine atoms in positions 11 and 12. The chemical modification of the carboxylic group in most cases results in a decrease or the loss of the activity.

Received: 10.01.2019
Revised: 04.02.2020
Accepted: 27.02.2020

Aim. To provide a brief literature review regarding the structure of the human coronavirus SARS-CoV-2, the mechanism of its replication and the role of viral proteases in this process; to analyze the ability of the known antiviral agents and compounds synthesized de novo in order to bind and inhibit the coronavirus main protease using computer simulation tools.

Results and discussion. COVID-19 coronavirus has become a worldwide challenge in recent months. Taking into account the rapid spread and severity of COVID-19 among a significant part of the population there is an urgent need to develop effective medicines and appropriate treatment protocols, which, unfortunately, are not yet available. Currently, the search for molecules with an acceptable toxicity profile that are able to inhibit and/or stop coronavirus SARS-CoV-2 replication in the human body is very relevant. In this study, the virtual screening and molecular docking of both antiviral agents known and new compounds synthesized have been performed based on the structure of the main protease M^pro of SARS-CoV-2. The regularities identified during our study can be useful for searching and developing new antiviral drugs to control COVID-19 and other coronavirus infections. The analysis of the results of calculations of physicochemical characteristics of antiviral agents, as well as the determination of their binding sites with the main viral protease M^pro gives an optimistic assessment of the possibility to develop new drugs based on the structures of the known antiviral drugs or their modified analogs.

Experimental part. Based on recent studies of the crystal structure of the virus main protease M^pro in the complex with various inhibitors (Protein Data Bank http://www.rcsb.org/pdb, the structure code – 6LU7) the virtual screening and molecular docking of 100 known antiviral agents and 50 novel compounds synthesized were performed. The screening data for the in vitro antimalarial activity of the compounds synthesized were presented. The following binding and physicochemical parameters of the ligand–protein interaction for all virus main protease potential inhibitors were calculated: binding affinity score (BAS), binding energy, lipophilicity (clogP) and topological polar surface area (TPSA). The protein and ligand structures were studied using Jmol, PyMol, and Avogadro graphics software packages. The virtual screening and molecular docking, as well as the analysis of the results were performed using a LigandScout 4.4 software package. Data on the antimalarial activity of 50 compounds synthesized were obtained from the Laboratory of Microbiology, Parasitology and Hygiene of theUniversity ofAntwerp (Belgium).

Conclusions. According to the results of the virtual screening and molecular docking with protein 6LU7 it has been found that a number of the known antiviral drugs have a certain potential for their use as inhibitors of SARS-CoV-2 coronavirus main protease. Remdesivir and ritonavir substances have shown higher activity than the reference compound of the 6LU7 complex. The molecular docking of a series of compounds recently synthesized with the proven in vitro antimalarial activity has revealed that L1 – L6 compounds are promising candidates for further modification and development of new antiviral drugs to control coronavirus infection.

Received: 02.04.2020
Revised: 23.05.2020
Accepted: 29.05.2020

Aim. To analyze and summarize the synthetic potential of 1,2,3-triazole-4(5)-amines as efficient building blocks in the synthesis of triazolo-annulated pyridine, azine and azepine systems.
Results and discussion. Original literature sources revealing the synthetic potential of 4(5)-amino functionalized 1,2,3-triazoles as convenient and available building blocks for the preparation of triazolo-annulated pyridines, azines and azepines were analyzed and systematized. Condensation of 1,2,3-triazole-4(5)-amines with methylene active compounds was shown to be a powerful tool for the synthesis of versatile triazolo[4,5-b]pyridines. In turn, the cyclocondensation based on 5-amino-1,2,3-triazole-4-carboxylic acids and their structurally modified derivatives was proven to be a general way for obtaining a number of triazolo[4,5-d]pyrimidine systems. Few representatives of triazolo-annulated pyridazines, 1,3-oxazines and 1,3-thiazines were synthesized by the intramolecular cyclization of the corresponding 4-aryl(carboxy-, aminomethyl)-5-amino-1,2,3-triazoles. The cyclocondensation involving 4,5-diamino-, 4-carbofunctionalized 5-amino-1,2,3-triazoles and 4-amino-5-thiocarboxamido-1,2,3-triazoles was successful for the construction of di-, oxa- and thiazepino-annulated triazoles.
Conclusions. The analysis, systematization and summary of the literature regarding the synthetic potential of 1,2,3-triazole-4(5)-amines conclusively demonstrate that these structures are easily available and convenient molecular blocks for the construction of triazolo-annulated pyridine, azine and azepine systems that are important for synthetic and biomedical research.