卷 74, 编号 1 (2019)

A new method for the detection of outliers in training sets used in QSAR model construction is developed. The method is based on the analysis of structure–activity–similarity (SAS) maps. It involves an empirical assessment of the likelihood of a chemical compound appearing in a particular SAS area. We propose to regard the compounds that have the maximal probability of an “activity cliff” (AC) region and the minimal probability of appearing in a “smooth region” (SR) as outliers. The method proposed can be used in the field of medicinal chemistry to search for new promising biologically active chemical compounds.

The influence of the synthesis conditions and composition of the reaction medium on the size and morphology of copper nanoparticles is studied for the Cu(II)—N₂H₄–sodium dodecyl sulphate systems. In accordance with scanning electron microscopy, the nanoparticles size varies in the range of 30 to 90 nm at the average diameter of 40 to 45 nm and spherical shape of copper nanoparticles. The dimensions of copper nanoparticles are evaluated to be up to 400 nm. As shown via the spectrophotometry, the stabilization of copper dispersions resistant to oxidation, as well as their aggregation and sedimentation, occurs at Cu(II): N₂H₄ molar ratios of 1 : 100; 1 : 200, and 1 : 300 in sodium dodecyl sulphate micellar solutions. A hypsochromic shift of the surface plasmon resonance absorption band of copper is established to occur in the range of 574 nm–568 nm–564 nm with a change of the Cu(II): N₂H₄ molar ratio.

The results of the mass spectrometric studies of a series of substituted isomeric pyrrolo[2,3-g], [3,2-f], [3,2-g], and [2,3-f]quinolines are presented and analyzed. Angular pyrroloquinolines with bulk peri substituents are less stable under electron ionization conditions than the corresponding linear isomers. The differences in the magnitude of the ratio of the intensity of a molecular ion peak to the total ionic current expressed as a percentage (W_M) depend on the steric requirements of peri-located groups in angular systems. The data obtained make it possible to identify the structure of the resulting isomeric tricyclic heterosystems. A mechanism for the mass spectral decomposition of methyl-, phenyl-, methoxy-, hydroxyl-, and ethoxycarbonyl-substituted pyrroloquinolines is proposed.

The technique of the quantitative determination of the sum of flavonoids based on rutin in the Canadian Goldenrod herb is modified by the method of differential spectrophotometry. Optimal conditions for the extraction of flavonoids from the Canadian Goldenrod are chosen depending on the concentration of the extracting solvent, the fineness factor of the raw materials, and the concentration of the complexing agent. The method is validated for accuracy, reproducibility, repeatability, and linearity.

Using a Nakhchivan natural mineral as a base, zeolites of different structural types are synthesized. Natural zeolite is modified under hydrothermal conditions in aqueous solutions of LiOH, KOH, NaOH, and Ca(OH)₂, as well as in the presence of mineralizers (LiCl, KCl, NaCl, CaCl₂) in an autoclave. Based on the data of IR-spectroscopic, X-ray phase, and elemental analyses, it is shown that during the hydrothermal treatment, natural zeolite is transformed into other minerals of the zeolite group that are important in practice. It is found that mordenite retains the structure’s stability in the alkaline solutions with a concentration of 1 N at a temperature of up to 100°C for 10 h. When the conditions of hydrothermal treatment change, natural zeolite gradually transforms into hydrosodalite through the mineral phases: chabazite, heulandite, clinoptilolite, analcime, phillipsite, faujasite, scapolite, zeolite M, gismondine, leucite, and kalsilite. The presence of mineralizers in the environment leads to the production of structural types of zeolites that differ from those obtained in a thermal solution.