Vol 87, No 4 (2017)

Structural, spectral, and thermodynamic characteristics of complex amidoboranes M²[M¹(NH₂BH₃)₄] (M¹ = Al, Ga; M² = Li, Na, K, Rb, Cs) were calculated by the B3LYP/def2-SVPD quantum-chemical method. The procedure for the synthesis of these compounds by reactions of alkali metal amidoboranes with aluminum and gallium chlorides was suggested and experimentally tested. Reaction products were characterized by the NMR and IR spectroscopy and X-ray phase analysis.

Manganese oxide sols were synthesized using the chemical condensation method by KMnO₄ reduction with polyvinyl alcohol in an aqueous medium. The resulting gels were characterized by the manganese oxide content of 0.07–0.19 wt %, pH 9.5–10.2, and ζ-potential of–(20.3–42.9) mV. Spectrophotometric, turbidimetric, and dynamic light scattering methods were employed to determine how the particle size, ζ-potential, pH, and manganese oxide content in the resulting sols were affected by the KMnO₄ concentration and the KMnO₄ : polyvinyl alcohol ratio. The most stable sols preserved stability for over180 days and remained stable up to 0.5 M KCl, CaCl₂, and AlCl₃ concentrations.

Mechanisms of the reaction of di- and trihydroxybenzenes with 2,2′-diphenyl-1-picrylhydrazyl (stable radical) in aprotic media of different polarity have been elucidated by experimental and quantum-chemical methods. Kinetic, stoichiometric, and activation parameters of the reaction have been determined. In benzene (nonpolar solvent), the studied reaction occurs via the hydrogen atom transfer mechanism; in the polar solvent with weak ionizing ability (i.e. DMSO), the reaction predominantly occurs via the faster mechanism of coupled electron and proton transfer.

Elementary acts of photoreactions of substituted 2,6-dimethyl- and 2,6-di-tret-butyl-1,4-benzoqionones and thiols have been studied using the methods of flash-photolysis and nuclear chemical polarization.

New aminomethoxy derivatives of 1-(butylsulfanyl)pentane have been synthesized. The structure of the synthesized compounds was studied by elemental analysis, IR and ¹Н NMR spectroscopy, and mass spectrometry. Some specimens of the synthesized compounds were tested as antimicrobial additives to lubricant oil, and as aseptic compounds against bacteria and fungi.

The mechanism of the formation of 5-substituted 1H-tetrazoles from organic nitriles and thiocyanates in the presence of NaN₃ and ZnCl₂ in aliphatic alcohols was studied. The results of this study allowed efficient methods of synthesis of substituted tetrazoles from nitriles, thiocyanates, and isothiocyanates to be proposed.

Reaction of chloromethyl derivatives of ethyl 3-furyl-3(diethoxyphosphoryl)acrylates with sodium azide in acetonitrile in the presence of catalytic amount of potassium iodide proceeds with substitution of halogen with the azido group. The same chloromethyl derivatives react with potassium thiocyanate under analogous conditions to give a mixture of thiocyanates and isothiocyanates in (0.6–0.8) : 1 ratio save the case of ethyl 3-(3-chloromethylfur-2-yl)- and 3-(4-chloromethylfur-3-yl)acrylates when only thiocyanates are formed. Bromination of diethyl 5-methyl-2-furoyl phosphonate with N-bromosuccinimide afforded 5-bromomethyl-2-furoyl phosphonate. In the reaction with potassium thiocyanate it forms only thiocyanate.

The competition between tetra-, penta-, and hexacoordination with the MN₂O₂, MN₂O₂X, and MN₂O₂X₂ (X = S, Se) coordination nodes, respectively, during the formation of bisligand Zn(II), Cd(II), and Hg(II) complexes with bi- and tridentate heterocyclic azomethines has been studied by means of quantumchemical DFT simulation of the complex formation and further stereoisomerization. It has been found that pentacoordination was favorable for the Cd(II) and Hg(II) complexes, whereas the Zn(II) complexes are tetracoordinate.

Sulfo derivatives of 4-[(Z)-(R)-diazenyl]phthalonitriles were synthesized by diazotization and azo coupling of 4-aminophthalonitrile and used as precursors for the corresponding cobalt phthalocyanines. The latter were obtained by template synthesis in boiling polychlorinated benzenes. The spectral properties of the products were studied.

Physicochemical properties of aqueous solutions of L-aspartic acid with and without addition of chitosan have been studied by conductometry, potentiometry, refractometry, tensiometry, and viscosimetry. It has been shown that aspartic acid molecules take a cyclic configuration stabilized by hydrogen bonds in aqueous solution at c > 0.04 g/dL (298 K). The interaction of chitosan with aspartic acid results in the formation of the polymeric salt that dissociates in aqueous solution to give chitosan polycation [~(NH₃)⁺] and aspartate counterions. The addition of chitosan to solutions of L-aspartic acid results in progressive increase in the surface tension, absorbance, and refractive index as well as the change in hydrodynamic properties of the macromolecules. The polymeric salt exhibits polyelectrolyte properties in dilute aqueous solutions. The increase in temperature impairs the thermodynamic quality of the solvent for chitosan leading to the shrinkage of the polymer coils and, hence, to the decrease in the intrinsic viscosity of the system.

The possibility of group identification of organic compounds, specifically their assignment to the corresponding homologous series) on the basis of differential quantities, such as differences in their physicochemical characteristics or analytical parameters, is considered. The first example of using difference in the refractive indices at different wavelengths for the determination of the overall concentration of aromatic hydrocarbons in gasoline fractions is described. Various methods for the assignment of unknown compounds to homologous series are analyzed, in particular those based on the limiting values of refractive indices and relative densities, differences in gas chromatographic retention indices on stationary phases of different polarities, combinations of gas chromatographic retention indices with partition coefficients for heterogeneous organic solvent systems, and two versions of combinations of mass spectrometric and GC parameters, namely molecular retention indices and homologous increments of retention indices. The latter version (as the most important) is illustrated in detail by a particular example.

Efficient synthesis of quinazoline derivatives via rhodium-catalyzed dehydrogenation and ring-closing method was developed with moderate to high yields.

A highly efficient, one-pot synthesis of functionalized tetrahydropyridines by multicomponent condensation of ethyl acetoacetate, two equivalents of aromatic aldehyde, and aromatic amine in the presence of a catalytic amount of NO₂-Fe(III)PcCl@C is reported. In this way, a series of pharmacologically interesting substituted pyridine derivatives were obtained in moderate to good yields.

Reduction of 1,5-dimethoxy-4-nitronaphthalene by hydrazine hydrate was optimized in the course of current study. Influence of metals, temperature and solvents upon the process was tested. Yield of the reaction was the highest in the presence of Zn powder in DMF. Moderate heating made the process slightly more efficient than that at room temperature, whereas high temperature led to a decreased yield. The current approach made it possible to exclude high pressure and diminish experimental costs.

A series of new 1-{[1-(3-chlorophenyl)-3-(4-methoxyphenyl)-1H-pyrazol-4-yl]methyleneamino}-6-amino-1,2-dihydro-4-(substitutedphenyl)-2-oxopyridine-3,5-di carbonitrile derivatives (4a–4i) were synthesized and characterized via cyclization of the key intermediate (E)-N'-([1-(3-chlorophenyl)-3-(4-methoxyphenyl)-1H-pyrazol-4-yl]methylene}-2-cyanoaceto hydrazide with different 2-arylidenemalononitrile.

New substituted (E)-phenyl{3-(2-[1-phenyl-3-(thiophen-2-yl)-1H-pyrazol-4-yl]vinyl)benzofuran-2-yl}methanones have been synthesized from substituted (E)-1-(2-hydroxyphenyl)-3-[1-phenyl-3-(thiophen-2-yl)-1H-pyrazol-4-yl]prop-2-en-1-ones and 2-bromo-1-phenylethanone under conventional and microwave irradiation conditions. The structures of the compounds were elucidated by IR, ¹H and ¹³C NMR, and mass spectra. The synthesized compounds were screened for their antibacterial and antifungal activities.

A novel synthetic approach to (E)-1-{[1-(3-chlorophenyl)-3-[(4-methoxyphenyl-1H-pyrazol-4-yl)- methylene]hydrazono}-3-phenylthiazolidin-4-one starting from the key intermediate thiosemicarbazone derivative is presented. The latter compound reacted with some aromatic and heterocyclic aldehydes to give (1-{[1-(3-chlorophenyl)-3-(4-methoxyphenyl)-1H-pyrazol-4-yl]methylene}hydrazono)-5-(substituted benzylidene)-3-phenylthiazolidin-4-one derivatives.

By an example of a reaction of N-bromohexamethyldisilazane with phenylacetylene the possibility of its homolytic addition to the triple carbon-carbon bond with the formation of a mixture of the corresponding E- and Z-isomers in the ratio of 1.2 : 1 was shown.

Reaction of 5-aminotetrazole triethylammonium salt and 2-fluoro-6-chlorobenzaldehyde resulted in the formation of 6-chlorotetrazolo[1,5-a]quinazoline instead of the expected azomethine. Hydrogenation of the obtained quinazoline afforded 6-chloro-4,5-dihydrotetrazolo[1,5-a]quinazoline.

Allobetulin N-acetylglucosaminide has been synthesized and shown to exhibit selective bacteriostatic activity against Staphylococcus aureus ATCC 209p with a minimum inhibitory concentration of 15.5 μg/mL.

Mixed-ligand platinum(II) complex with ethylenedithiodiacetic acid (HSSH) and thioglycolic acid has been synthesized. Ethyleneditiodiacetate is coordinated to platinum through the sulfur atoms in the bidentate mode, whereas thioglycolic acid acts as a unidentate ligand which is coordinated to platinum in the cis position through the sulfur atom. The carboxylic group of thioglycolic acid is not involved in coordination. The complex exhibits cytotoxic properties.