Vol 93, No 5 (2023)

The sulfonamide with a benzothiazine moiety was synthesized by a Diels-Alder reaction of thionylaniline with dicyclopentadiene. The prepared adduct was oxidized to the appropriate sulfonamide with a benzothiazine moiety. The molecular and crystal structure of the sulfonamide obtained was determined by the single crystal X-ray diffraction analysis. A higher reactivity of the the olefin function of the norbornene fragment was found; and the formation of two structural isomers was revealed.

This research focuses on studying derivatives of 2-oxaindane spiropyran by its condensation with aromatic amines. The results showed that all the synthesized compounds are enaminoketones form in both solution and solid state. This is explained by the fact that during the formation of Schiff bases, the proton of the 7-hydroxyl group of the benzopyran part migrates to the azomethine nitrogen, which leads to the transition of the cyclic form of spiropyran into the corresponding enaminoketone. In the DMSO solution, the enaminoketones dynamic equilibrium of the E , Z -isomeric forms were observed. The structure of enaminoketone based on 3,4-dimethylaniline was proved by the X-ray diffraction method. The synthesized compounds were studied for their in vitro anticancer activity against human hepatocellular carcinoma (HepG2), breast carcinoma (MCF-7), lung cancer (A549), and carcinoma cells (KB). Enaminoketone with R = 3,4-СH₃Ph is characterized by the highest activity, with IC₅₀ values of 13.38 μM (KB). The results in vitro antioxidant activity test using 1,1-diphenyl-2-picrylhydrazyl (DPPH) indicated that enaminoketones were inactive.

New tetrazole-containing derivatives of morpholin-4-yl-1,3,5-triazine and 4-methylpiperidin-1-yl-1,3,5-triazine were synthesized. Cytotoxic activity of the compounds obtained against human liver tumor cell lines Huh-7 and human lung A549 was studied by the MTT test. It was shown that these substances do not exhibit a pronounced cytotoxic effect. The most significant antitumor activity was shown by 1,3,5-triazine containing 5-phenyltetrazol-2-ylacetohydrazide fragment and 4-methylpiperidine ring as substituents, as well as 1,3,5-triazine containing 5-methyl-1 H -tetrazol-1-ylacetohydrazide fragment and two morpholine rings. For these compounds, the interaction with DNA was studied by UV spectroscopy. For N ’-(4,6-dimorpholino-1,3,5-triazin-2-yl)-2-(5-methyl-1 H -tetrazol-1-yl)acetohydrazide, the DNA binding constant was determined ( K _bin 9.02× 10⁴ M.^-1) and studied the ability to inhibit the tyrosine kinase domain of surface receptors. It was shown that the studied tetrazole-containing derivatives of 1,3,5-triazine do not exhibit antioxidant properties with respect to NO-radicals and do not cause photoinduced hemolysis.

NMR spectra of 1-propylimidazole-4,5-dicarboxylic acid in DMSO- d ₆ were studied. It was revealed that it presents in a zwitterion form in solution. The ionization constants in water were determined and their attribution to the certain sites was performed, at that for the deprotonation constants, the correctness of the attribution was confirmed by calculations. Based on the results of calculations, the preferred zwitterion and monoanion forms of 1-propylimidazole-4,5-dicarboxylic acid were selected from several alternative structures.

The supramolecular structure of N -(6-bromocyclohex-3-en-1-yl)- and N -(7-bromobicyclo[2.2.1]hept-2-yl) N ′-(triflyl)ethanimidamide was analyzed according to XRD and IR spectroscopy in various states in a wide temperature range and quantum chemical calculations. The supramolecular structure of the studied amidines is based on linear dimers of the E-syn -conformer with N-H∙∙∙O=S hydrogen bonds, which form polymer chains. The layered structure of N -(6-bromocyclohex-3-en-1-yl)- N ′-(triflyl)ethanimidamide is formed by C-H∙∙∙O, C-H∙∙∙Br, and C-H∙∙∙F contacts, and in the case of N -(7-bromobicyclo[2.2.1]hept-2-yl)- N ′-(triflyl)ethanimidamide by C-H∙∙∙O contacts. The molecular electrostatic potential maps of the studied amidines were obtained and their correspondence between the strengths of H-bonds and shortened contacts in both compounds was shown. Comparison of experimental and calculated frequencies ν(NH) in monomers and dimers of N -(6bromocyclohex-3-en-1-yl)- N ′-(triflyl)ethanimidamide showed the presence of conformational E-syn → E-anti transitions with the formation of cyclic dimers, the proportion of which increases with decreasing temperature.

Palladium(II) extraction from nitric acid solutions with a complex-forming reagent, 4-[(hexylsulfanyl)methyl]-3,5-dimethyl-1-phenyl-1 H -pyrazole, was studied using chloroform as a diluent. The reagent extracts Pd(II) with high efficiency from 0.5-5 M. HNO₃ solutions. It has been established that palladium(II) is extracted from 2 M. HNO₃ solutions by a coordination mechanism with the formation of the extracted compound [Pd(NO₃)₂μ-L] _n ( n > 2). Palladium(II) is quantitatively stripped with a nitric acid solution of thiourea. The reagent is promising for the concentration of Pd(II) from nitric acid solutions and its highly selective separation from Fe(III), lanthanides(III), Al(III), Cu(II), and Ni(II).

The work is devoted to the study of the complex formation of sulfasalazine with native and polymeric β-cyclodextrins in buffer solutions with a physiological pH value using isothermal saturation and ¹H NMR methods. It was established that sulfasalazine forms two types of complexes when interacting with the cyclodextrins under consideration, but only the process of formation of inclusion complexes determines the observed increase in drug solubility, which is more pronounced in the presence of polymeric β-cyclodextrin. It was determined that complexation with β-cyclodextrin and its polymeric derivative leads to a decrease in the permeability coefficients of sulfasalazine through the model membrane, which is determined by both the stability constant of the complexes and their ability to pass through the membrane.

The work is devoted to the study of a supramolecular system based on viologen calix[4]resorcinol and sodium alginate in an aqueous medium using a set of physicochemical methods. It was established that sodium alginate and viologen calix[4]resorcinol form stable nanoparticles capable of encapsulating hydrophobic biologically active substances in the range of macrocycle:polymer concentration ratios from 1:2 to 1:10. The study of the cytotoxic properties of these nanoparticles in the presence of encapsulated substrates showed an increase in the selectivity of the action of quercetin and oleic acid against M-HeLa tumor cells by 2.47 and 1.14 times, respectively.