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Antimicrobial resistance is a never-ending challenge, which should be considered seriously, especially when using unprescribed "over-the-counter" drugs. The synthesis and investigation of novel biologically active substances is among the directions to overcome this problem. Hence, 18 novel 5,6-dihydrotetrazolo[1,5-c]quinazolines were synthesized, their identity, purity, and structure were elucidated by elemental analysis, IR, LC-MS, 1 Н, and 13 C NMR spectra. According to the computational estimation, 15 substances were found to be of toxicity Class V, two of Class IV, and only one of Class II. The in vitro serial dilution method of antimicrobial screening against Escherichia coli, Staphylococcus aureus, Klebsiella aerogenes, Pseudomonas aeruginosa, and Candida albicans determined b3, c1, c6, and c10 as the "lead-compounds" for further modifications to increase the level of activity. Substance b3 demonstrated antibacterial activity that can be related to the calculated high affinity toward all studied proteins: 50S ribosomal protein L19 (PDB ID: 6WQN), sterol 14-alpha demethylase (PDB ID: 5TZ1), and ras-related protein Rab-9A (PDB ID: 1WMS). The structure-activity and structure-target affinity relationships are discussed. The targets for further investigations and the anatomical therapeutic chemical codes of drug similarity are predicted.

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The present article is devoted to searching for biologically active agents among novel thio-containing pteridines. Synthetic protocols based on the condensation of 5,6-diamino-2-thioxo-2,3-dihydropyrimidin-4(1H)-ones with dicarbonyl compounds were elaborated and used for the synthesis of target products. The directions for further modification of the obtained thio-containing pteridines were substantiated and realized. The spectral properties of the obtained compounds were studied and described. The results of the in silico study revealed that the predicted affinity of the obtained compounds to the dihydrofolate reductase (DHFR) active site is comparable with the affinity of methotrexate, despite the differences in the nature of the ligand-enzyme interactions. The in vitro study of DHFR-inhibiting activity revealed that the most active compounds 3.9 and 4.2 have lg IC50 values of -5.889 and -5.233, respectively, significantly inferior to methotrexate (lg IC50 = -7.605). Additionally, the synthesized compounds were studied for their antiradical activity as a possible mechanism of pharmacological effects. Among the obtained pteridines, compounds 5.1 (lg EC50 = -4.82) and 5.3 (lg EC50 = -4.92) have antiradical activity higher than the reference compound ascorbic acid (lg EC50 = -4.81). The conducted structure-activity relationship analysis provided valuable data for the further search for biologically active agents among thio-containing pteridines and related compounds.

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BACKGROUND: Computer-aided drug design is among the most effective methods of medicinal chemistry. The above mentioned approach is used for the purposeful search of antiinflammatory agents among quinazoline condensed derivatives. OBJECTIVE: The study aimed to conduct a purposeful synthesis of novel 3-R-2,8-dioxo-7,8-dihydro- 2H-pyrrolo[1,2-a][1,2,4]triazino[2,3-c]quinazoline-5a(6H)carboxylic acids and their salts as promising anti-inflammatory agents, evaluate their structure by physicochemical methods and establish their anti-inflammatory activity. METHODS: The structures of target compounds were proposed due to their structure similarity to existing drugs and experimental agents with anti-inflammatory activities. The features of the synthesized compounds structures were evaluated by IR-, NMR spectroscopy and chromatography-mass spectrometry and discussed in detail. Probable molecular mechanisms of activity were predicted by molecular docking. The anti-inflammatory activity was determined by their ability to reduce the formalin- and carrageenan-induced paw edema in rats. RESULTS: It was found that the condensation of 3-(2-aminophenyl)-6-R-1,2,4-triazin-5(2H)ones with 2-oxoglutaric acid yielded 3-R-2,8-dioxo-7,8-dihydro-2H-pyrrolo[1,2-a][1,2,4]triazino[2,3-c]quinazoline- 5a(6H)carboxylic acids which may be considered as a promising anti-inflammatory agent. An in silico study showed that the obtained compounds revealed affinity to the molecular targets and corresponded to the drug-like criteria. Additionally docking study allowed to estimate the nature of interactions between synthesized compounds and molecular targets. The in vivo experiments showed that the obtained compounds demonstrated significant anti-inflammatory activity comparable or higher than the activity of the reference drug Diclofenac. CONCLUSION: The developed and implemented search strategy of the anti-inflammatory agents was justified. 3-R-2,8-dioxo-7,8-dihydro-2H-pyrrolo[1,2-a][1,2,4]triazino[2,3-c]quinazoline5a(6H)carboxylic acids possessed the anti-inflammatory activity and additional introduction of fluorine atoms in position 11 or 12 of the heterocyclic system led to amplification of this activity.

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BACKGROUND: (Quinazoline-4-ylidene)hydrazides are valued intermediates in modern organic chemistry, as they are commonly used for the synthesis of substituted [1,2,4]triazolo[1,5-c]quinazolines. OBJECTIVE: Unknown N-acyl-2-([1,2,4]triazolo[1,5-c]quinazoline-2-yl)-alkyl-(alkaryl-, aryl-) amines were synthesized and evaluated for anti-inflammatory potential. METHODS: The peculiarities of the synthesized compounds structures were studied by IR-, NMR spectroscopy and chromatography-mass spectrometry and were discussed in detail. Probable molecular mechanisms of activity (inhibition of COX-1 and COX-2) were predicted due to molecular docking. Anti-inflammatory activity of synthesized compounds was determined by their ability to reduce the formalin-induced paw edema in rats. Diclofenac sodium was used as reference drug. RESULTS: In this study, the synthesis of N-acetyl-(benzoyl)-2-([1,2,4]triazolo[1,5-c]quinazolinе- 2-yl)alkyl-(aralkyl-, aryl-)amines, using (3H-quinazoline-4-ylidene)hydrazides of Nprotected amino acids or 4-hydrazinoquinazoline and N-prorotected amino acids as starting compounds was developed. It was established that the reaction of (3H-quinazoline-4- ylidene)hydrazides of Boc-amino acids occurred with the formation of N-acetyl-substituted triazoloquinazolines. High anti-inflammatory activity was detected for unknown (3Hquinazoline- 4-ylidene)hydrazides Boc-amino acids (1.13-1.15) and N-acetyl-(benzoyl)-2- ([1,2,4]triazolo[1,5-c]quinazoline-2-yl-)aralkyl-(aryl-)amines (3.2, 3.3, 3.11, 3.12), using the experimental formalin test. CONCLUSION: The conducted SAR-analysis allowed to detect critical fragments. Namely, the Boc-aminoaralkyl-(aryl-)acid residue in (3H-quinazoline-4-ylidene)hydrazides (1.13- 1.15), benzyl and phenyl linker groups in N-acetyl-(benzoyl)-2-([1,2,4]triazolo[1,5- c]quinazoline-2-yl-)aralkyl-(aryl-) amines (3.2, 3.3, 3.11, 3.12) are believed to be substantial for anti-inflammatory activity.

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A simple and effective method for the synthesis of unknown 1-methyl-7-arylfuro[3,2-g]pteridine-2,4(1H,3H)-diones by dehydration of the corresponding 1-methyl-6-phenacyl-pteridine-2,4,7(1H,3H,8H)-triones is reported in the article. It was shown that their alkylation by butyl chloroacetate in basic medium proceeded by the N3-atom of the heterocycle. The structure and purity of the synthesized compounds were confirmed by IR, 1H, 13C NMR spectroscopy, gas chromatography-mass spectrometry, mass spectrometry, as well as X-ray diffraction analysis. The proposed mechanism of the dehydration reaction was discussed.

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An effective synthesis of (3H-quinazoline-4-ylidene)hydrazides of N-carboxyalkyl-(arylalkyl-,aryl-)isoindoline-1,3-diones, using activated N-protected aminoacids and 4-hydrazinoquinazoline was proposed in the framework methodology of directed search of hypoglycemic agents (fragment-oriented design, molecular docking). These hydrazides prepared via cyclocondensation under acid catalysis were converted to the corresponding 2-([1,2,4]triazolo[1,5-c]quinazoline-2-yl-) alkyl-(alkylaryl-,aryl-)-hydroisoindole-1,3(2H)-diones. The structure of synthesized compounds was established using IR, 1H and 13C NMR spectroscopy and LC-MS and the features of spectral pattern were discussed. The results of pharmacological screening revealed a series of compounds, that are short-acting hypoglycemic agents like prandial regulators of glucose (Mitiglinide). The SAR analysis showed, that the introduction of a hydrogenated 1,3-dioxoisoindole moiety bonded through linker groups with 4-hydrazinoquinazoline and triazolo[1,5-c]quinazoline cycles is reasonable in the context of searching for short-acting hypoglycemic agents and requires further research.

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Present work is devoted to the purposeful search of novel promising anti-inflammatory agents among the insufficiently known 3'-R-10'-R1-spiro[hetaryl-3(4),6'-[1,2,4]triazino[2,3-c]quinazolin]-2'(7'H)-ones. The virtual combinatorial library of previously unknown spiro-condensed derivatives of [1,2,4]triazino[2,3-c]quinazolines was formed and promising COX-2 inhibitors were identified by molecular docking method. Potential anti-inflammatory agents were synthesized by [5+1]-cyclocondensation of substituted 3-(2-aminophenyl)-6-R-1,2,4-triazin-5(2H)-ones with heterocyclic ketones. The structures of synthsized compounds were verified by complex of physicochemical methods and spectral characteristics features were discussed. Obtained compounds were studied for anti-inflammatory activity using formalin induced paw edema model and highly active compounds were identified. Conducted SAR-analysis showed that combination of triazino[2,3-c] quinazoline moiety with spiro-condensed fragments is a reasonable approach for creating novel anti-inflammatory agents.

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Chemical compounds with tetrazole ring are very interesting systems that can be valuable in pharmaceutical and clinical applications, especially as anticancer agents. In this work, novel 6-N-R-tetrazolo[1,5-c]quinazolin-5(6H)-ones were synthesized. A large set of IR, LC-, EI-MS, 1H, 13C NMR and elemental analysis data were collected and evaluated for their structures and purity. Details of synthesis, namely the N-alkylation, are discussed, including reactions with secondary and tertiary amides. Four new synthesized compounds (2.7, 3.2, 5.2, 5.3) were tested in vitro for anticancer activity at 10 µM against 60 cell lines of nine different cancer types: leukemia, melanoma, lung, colon, CNS, ovarian, renal, prostate, and breast cancers. Further synthesis of substances within the series of substituted tetrazolo[1,5-c]quinazoline systems will be attempted to develop improved compounds with better anticancer activity.

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Methods of 1-[2-(1H-tetrazol-5-yl)-R(1)-phenyl]-3-R(2)-phenyl(ethyl)ureas and R(1)-tetrazolo[1,5-c]quinazolin-5(6H)-ones synthesis were designed. IR, LC-MS, (1)H NMR, and elemental analysis data evaluated the structure and purity of the obtained compounds. Different products, depending on the reaction conditions, were distinguished and discussed. The preliminary hypoglycemic activity of 36 synthesized compounds was revealed. Docking studies to 11ß-hydroxysteroid dehydrogenase 1, γ-peroxisome proliferator-activated receptor, and dipeptidyl peptidase-4 were conducted. Eight of these substances were further tested on glucocorticoid-induced insulin resistance models, namely glucose tolerance, oral rapid insulin, and adrenalin tests. One of the most active compounds turned out to be tetrazolo[1,5-c]quinazolin-5(6H)-one 3.1, exceeding the reference drugs Metformin (50 and 200 mg/kg) and Gliclazide (50 mg/kg).