Browsing by Author "Varenichenko, S. A."

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An Efficient Synthetic Route to Substituted Xanthene Analogues
(Ukrainian State University of Science and Technologies, Dnipro, 2025) Varenichenko, S. A.; Kovtun, A.V.; Farat, V. K.; Farat, O. K.
ENG: The reactions of N-[(9-chloro-1,2-dihydrocyclopenta[b]chromen-3-yl)methylene]-Nmethylmethanaminium and N-[(11-chloro-7,8,9,10-tetrahydrocyclohepta[b]chromen-6- yl)methylene]-N-methylmethanaminium perchlorates with (1- phenylethylidene)malononitrile were studied in boiling acetonitrile in the presence of piperidine. These reactions led to the formation of new organic dyes, [(2E)-1-phenyl-3- (9-piperidin-1-yl-1,2-dihydrocyclopenta[b]chromen-3-yl)prop-2-en-1- ylidene]malononitrile and [(2E)-1-phenyl-3-(11-piperidin-1-yl-7,8,9,10- tetrahydrocyclohepta[b]chromen-6-yl)prop-2-en-1-ylidene]malononitrile, obtained in high yields. The structures of the products were confirmed by 1H NMR spectroscopy, mass spectrometry, and elemental analysis. The observed spin-spin coupling constants indicated that the products adopted the E-configurations of the double bonds. The reaction mechanism was determined to proceed via a Knoevenagel condensation followed by nucleophilic substitution of chlorine with a piperidine fragment. Spectroscopic investigations of the dyes were performed in organic solvents, in particular acetonitrile and chloroform. For [(2E)-1-phenyl-3-(9-piperidin-1-yl-1,2-dihydrocyclopenta[b]chromen3-yl)prop-2-en-1-ylidene]malononitrile, the absorption maximum was ~605 nm, and the emission maximum was ~685 nm, with a quantum yield of 34.62% in acetonitrile and 16.84% in chloroform. In contrast, [(2E)-1-phenyl-3-(11-piperidin-1-yl-7,8,9,10- tetrahydrocyclohepta[b]chromen-6-yl)prop-2-en-1-ylidene]malononitrile exhibited an absorption maximum at 607 nm with negligible fluorescence. The synthesized dyes may be of interest to researchers in the field of dye chemistry and related areas.
Investigation of Antimicrobial Activity of 1,3-Benzoxazine Derivatives
(Інститут молекулярної біології і генетики НАН України, Київ, 2019) Zahorulko, S. P.; Varenichenko, S. A.; Farat, O. K.; Markova, Iryna V.; Markov, V. I.
EN: Aim. To investigate potential antimicrobial activity of 1,3-benzoxazines derivatives. Methods. Synthesis, antimicrobial screening, antimicrobial and antifungal activity testing in vitro. Results. For antimicrobial screening, we chose the compounds that differed from the investigated ones by 30 %. Five compounds were selected and their antimicrobial activity against five bacterium and two fungus strains was studied by the methods of microbial growth inhibition assay. The percentage of growth inhibition of an individual sample is calculated considering a negative control (media only) and a positive control (bacterial / fungal media without inhibitors). The results obtained showed that compounds 2-[5-(4-nitrophenyl)-1H-pyrazol-3-yl]phenol and 6,8-diisopropylspiro[1,3- benzoxazine-2,1’-cyclohexan]-4(3H)-one in concentration of 32 μg/ml have the highest activity against Acinetobacter baumannii - 43 % and 27 %, respectively. The compound, 6,8-diisopropyl- 2-methyl-2-(4-nitrophenyl)-2,3-dihydro-4H-1,3-benzoxazine-4-one showed the fungicidal activity against the Candida albicans strain. Conclusion. The derivatives of 1,3-benzoxazines exhibit a moderate antimicrobial activity, which allows the recommendation to continue the search for effective antimicrobials among the chemical compounds of this group, in particular, through the targeted synthesis of new compounds with predicted antimicrobial properties.