Voprosy khimii i khimicheskoi tekhnologii (Issues of Chemistry and Chemical Technology)

3-9

Authors: I.R. Buchkevych, M.S. Kurka, V.G. Chervetsova, A.S. Krvavych, N.Ya. Monka, V.I. Lubenets, V.P. Novikov

The paper reports the synthesis of imidazole systems based on derivatives of 6,7-substituted 1,4-naphthoquinone, both those condensed with the naphthoquinonic cycle and the derivatives in which the heterocyclic component was introduced into the quinoid molecule as a separate fragment. The work was done in order to extend the spectrum of the biology action of the synthesized compounds due to the combination of imidazole and naphthoquinoid fragment in a single molecule. A series of 6[(5-amino-2,3-dihydro-1H-1,2,4-triazol-3-yl)-amino]-3-chloro-2-substituted-4-yl-7-nitronaptoquinones, 2,7-dichloro-6-(2,5-dimethyl-1H-pyrrol-1-yl)-3-R-4-yl-nitronaptoquinones and thioxoquinoxalinic derivatives of substituted 1,4-naphthoquinone was synthesized. The conducted studies of antimicrobial and fungicidal activities showed that the introduction of an additional aminotriazole substituent at the position 6 into the molecule of 1,4-naphthoquinone reduces the effect on both gram-positive and gram-negative bacteria. The presence of a pyrrole cycle at the position 7 of 1,4-naphthoquinone increases the activity against gram-positive and gram-negative bacteria. The presence of a thioxoamide cycle at the position 7 of 1,4-naphthoquinone significantly increases the activity against gram-positive and gram-negative microorganisms. Thus, the obtained results may be used for further development of effective antibacterial and antifungal chemotherapeutic remedies.

18-24

Authors: D. Girenko, O. Shmychkova, A. Velichenko

It was shown that the pre-reduced surface of the platinized titanium electrode undergoes a series of transformations during the anodic polarization. Oxygen-containing particles OHads are chemisorbed on the Ti/Pt surface in the low polarizations range. Such particles, depending on the pH of the near-electrode layer, can be in equilibrium with OH2+ads and O–ads. With increasing polarization, the formation of both atomic oxygen and phase oxide layers becomes possible. The formation of phase surface oxides occurs rapidly in supporting electrolytes, and the oxygen evolution proceeds on a completely oxidized surface. The presence of chloride ions in solution significantly decelerates this process. The higher the Cl– concentration, the longer the surface remains in the reduced state. The chloride ion acts as a depolarizer, discharging on the surface and interacting with surface oxygen-containing particles, thereby slowing down the oxidation of the surface. It was established that both direct oxidation of Cl– and its oxidation by labile oxygen-containing particles of the OHads type occur on the reduced platinized surface. On the oxidized surface, the formation of hypochlorite occurs directly on the surface of the layer of platinum phase oxides with the participation of inert chemisorbed oxygen-containing particles and atomic oxygen. The desorption of the products of primary oxidation of Cl– becomes slower, and an increase in the degree of surface filling with active oxygen-containing particles of the Oads type leads to a significant increase in the rate of chlorate formation.

33-38

Authors: Y.I. Koltsova, S.V. Nikitin

This paper reports the results of the study devoted to the preparation of porous glass-ceramic materials by using fuel slag at the temperatures no more than 950C. Glass slag compositions containing 20 to 70 wt.% of glass cullet and 30 to 80 wt.% of fuel slag were investigated. In order to reduce the sintering temperature, various salts were added to their composition, among which Ca(NO3)24H2O and Na2CO3 had the strongest influence on sintering. The introduction of 9 to 15 mass parts of Na2О (introduced as Na2CO3) into the composition and the use of manganese carbonate as a gas-forming agent allowed obtaining porous glass-ceramic materials having bloating coefficient KV=0.77–1.35 and KV=0.77–2.33 at the firing temperatures of 900C and 850C, respectively. If loam was used as a gas-forming agent, the bloating coefficient was equal to 0.55–0.83 and 0.93–1.64 at the firing temperatures of 900C and 850C, respectively. The obtained materials had an uneven macroporous structure due to intense gas evolution. The preliminary heat treatment of the glass slag compositions at the temperature of 950C with subsequent grinding the cake and introducing gas-forming agents resulted in the formation of porous glass-ceramic materials with a sufficiently high bloating coefficient (~4.68 at the firing temperature of 700C) and homogeneous micro- or mesoporous structures (the coefficient of inhomogeneity of the structure being 0.17 and 0.18, respectively).

47-52

Authors: T. Rymar, O. Suvorin

The article reports two methods of preparation of block thermal insulation materials based on liquid glass; a comparative assessment of them is performed. These methods are implemented via volume and contact grouting of the liquid glass granules by the microwave-assisted swelling of a binder. In order to determine the effectiveness of a certain grouting method, the samples were swollen at different power capacities of a microwave oven and the basic operational characteristics of blocks were determined. The obtained results showed that the materials fabricated by volume grouting are characterized by higher strength and lower moisture sorption and water absorption properties than that prepared by contact grouting due to a closer packing of granules and more uniform distribution of the binder in the intergranular space. This is achieved through the use of microwave irradiation in the production of block materials, which ensures uniform heating of all layers of the material and simultaneously allows swelling both the granules and the binder. Therefore, a strongly grouted material is obtained, which can be used as a structural thermal insulation.

61-70

Authors: V. Stavytskyi, О. Voskoboinik, М. Kazunin, I. Nosulenko, S. Shishkina, S. Kovalenko

The heterocyclization of 3-(2-aminophenyl)-6-(4-isopropylphenyl)-1,2,4-triazin-5(2H)-one with 4-oxoheptanedioic acid was studied in this work. It was shown that this reaction yielded partial hydrogenated [1,2,4]triazino[2,3-c]quinazoline, pyrrolo[1,2-a][1,2,4]triazino[2,3-c]quinazoline-5a(6H)-yl)propanoic acid or their mixture depending on the reaction condition (the nature of a solvent, the temperature, and the process duration). It was found that the refluxing of initial compounds in acetic acid was the most suitable in the case of the synthesis of 3-(3-(4-isopropylphenyl)-2,8-dioxo-7,8-dihydro-2H-pyrrolo[1,2-a][1,2,4]triazino[2,3-c]quinazolin-5a(6H)-yl)propanoic acid. The found optimal conditions were used for the condensation of 2-azaheterylanilines with 4-oxoheptanedioic acid. These conditions created the basis for preparative methods for the synthesis of tetracyclic derivatives series. The structure and purity of the obtained compounds were determined by a complex of appropriate physicochemical methods, including 1Н and 13С NMR, IR, chromatography-mass, mass-spectroscopies and X-ray diffraction analysis. The features of the fragmentation of different heterocycles molecular ions under electronic ionization were discussed. It was established that the destruction of pyrrolidone cycle caused higher fragmentation of aromatic pyrrolo[1,2-a][1,2,4]triazоlo[1,5-c]quinazoline system. It was found that the introduction of carboxyethyl fragment into the pyrrolo[1,2-a][1,2,4]triazino-)[2,3-c]quinazoline system was favorable for the formation of anti-inflammatory agents. Pharmacological studies revealed that only substituted pyrrolo[1,2-a][1,2,4]triazino[2,3-c]quinazoline-5a(6H)-propanoic acids showed high anti-inflammatory activity. The series of the obtained compounds demonstrated an anti-inflammatory activity that was comparable to or higher than the pharmacological effect of the reference compound "diclofenac". The essential role of the presence of fluorine atom in the anti-inflammatory activity of the synthesized compounds was discussed.

80-85

Authors: N.Yu. Strutynska, D.О. Danilchuk, M.S. Slobodyanik

The paper reports the peculiarities of the formation of calcium phosphates via precipitation from aqueous solutions in the systems Сa2+–M–PO43––NO3– (where M=Cs+, Zn2+ or Cr3+) at the molar ratios Са2+/РО43–=1.5 and 1.67 and Сa2+/M=2.0; 3.0 or 15.0 and the temperature of 25C. The precipitated samples were heated to the temperatures of 700 and 900C to provide intercalation of impurity cations (M) into the structure of calcium phosphates. The effects of the cation nature (М) and the molar ratio Сa2+/М on the formation of apatite- and whitlockite-related calcium phosphates were established. The mixture of apatite and whitloskite-type phases was obtained for Cs- and Zn-containing systems at the molar ratio Сa2+/М=2.0 and 3.0 in the initial solution, whereas the formation of only apatite-related phase was observed with a significant increase in the value Сa2+/М (up to 15.0). The presence of chromium cation in the initial solution caused the stabilization of a phase based on -Са3(РО4)2 (whitlockite type), while an apatite-related phase is formed in the case of a mixture of Cs+, Zn2+ and Cr3+ cations. The fabricated samples were characterized using powder X-ray diffraction and FTIR-spectroscopy methods. The optimized conditions for the binding of cesium, zinc and chromium cations to form stable apatite- and whitlockite-related calcium phosphates can be further used to develop methods for the immobilization of radioactive isotopes.

92-96

Authors: O.K. Farat, E.V. Zaliznaya, S.A. Varenichenko, V.I. Markov

The study of the formylation of a geminal system N1–C2–O3 of spiro-3,1-benzoxazines revealed that they are rearranged into hydroacridones with a quantitative yield for 30 minutes when interacting with an equivalent amount of Vilsmeier-Haack reagent at room temperature. If one uses a three-fold excess of Vilsmeier-Haack reagent, chlorine derivatives of hydroacridine are also produced at room temperature with a quantitative yield for 1 hour. It should be noted that hydroacridones have been earlier isolated only as by-products with a low yield. The absence of the C–2 carbon atom signal in the 13C NMR spectra of the products, unlike the starting compounds, where the C–2 signal corresponds to a chemical shift of 89.1–89.2 ppm, testifies to the rearrangement of the carbon skeleton. The chemistry of acridines seems to be interesting and promising due to the biological activity of these compounds. For example, the derivatives of hydroacridine chlorine are key intermediates in the synthesis of monomeric and dimeric derivatives of Tacrine, which are used as acetylcholinesterase inhibitors in the treatment of Alzheimer's disease.

104-110

Authors: T.V. Chernozhuk

The constants of the association (КА), the non-Coulomb interaction parameters (d+–) and the parameters of the Gurney cosphere overlap (А+–) in solutions of 1-1 electrolytes in -butyrolactone (-BL), propylene carbonate (PC) and their mixtures with 1,2-dimethoxyethane (PC+1,2-DME) (1:1) were calculated using experimental data. The effects of temperature, concentration, properties and sizes of particles on interparticle interactions in the investigated solutions of 1-1 electrolytes in -BL, PC and PC+1,2-DME (1:1) were determined. It was established that the square-law potential d+– strongly depends on the solvent nature, temperature and ion size, while the parameter А+– shows a much weaker dependence. This can be used to predict the values of А+– and the ion association constants for a wide range of electrolytes in a given solvent when only limited experimental data are available.