Home – Home – Jornals – Chemistry for Sustainable Development 2022 number 6

The chromatographic behavior of a number of human blood plasma metabolites in HPLC-MS/MS analysis using a monolithic chromatographic column with a 1-vinyl-1,2,4-triazole-based sorbent was studied. Acetonitrile and a buffer based on ammonium carbonate and ammonia (pH 9.8) were used as the mobile phase. The experiment was carried out in two chromatographic modes: reversed-phase and hydrophilic. The metabolites selected for analysis allow for an unambiguous demonstration of the behaviour of both polar molecules and hydrophobic or amphiphilic lipid molecules in both of the chromatographic modes used. It was discovered that the change of chromatographic regime was accompanied by an inversion of the order of elution of metabolite groups having differences in chemical structure and hydrophilicity. It was shown that this 1-vinyl-1,2,4-triazole-based monolithic column can be used to screen metabolites in both reverse-phase and hydrophilic chromatography modes, and the use of two chromatography modes in metabolome screening using this column is mutually complementary and can help to increase the coverage of metabolites from different metabolic pathways.

In view of the 2^nd type diabetes mellitus "epidemic" developing over the world, and the absence of any efficient and safe drug therapy, the search for new hypoglycemic agents is a highly relevant task. Usnic acid produced by lichens, in addition to its diverse biological effects, also exhibits hypoglycemic action, though only in high doses. To decrease the effective hypoglycemic dose and reduce the risk of side effects, in the present work usnic acid was modified through reactions with the amino acid β-alanine and its derivatives. The hypoglycemic effect of the synthesized enamine derivatives of usnic acid was investigated in mice with alloxan-induced diabetes mellitus. It was determined that the derivative containing the amide fragment in the substituent exhibited a clearly pronounced hypoglycemic effect at the dose of 50 mg/kg. Neither of the studied compounds exhibited activity in the oral glucose-tolerance test in mice without any carbohydrate metabolism disorders.

Results of the multidisciplinary investigation of unique cult objects of the Ob Ugrians are reported. These objects were discovered during field work in the Berezovsky district of Khanty-Mansi Autonomous Territory - Yugra. The first item is a head scarf, which is a sacrificial gift to the Mansi deity Mis-Ne (Forest Woman); the second is a fragment of clothing of an ittarma figure (the Khanty family spirit). The third item (a head scarf) had no embroidery, but part of it was made of handmade fabric. The artefacts were used in the ritual practice of the northern groups of the Ob Ugrians and were probably imported, since the art of embroidery and the skills of hand-weaving existed in the 18^th-19^th centuries only among the southern groups of the Khanty and Mansi. The analysis of fibres and identification of embroidery dyes for hand-woven products of the turn of the 18^th-19^th centuries were carried out. The samples were studied by IR spectroscopy, scanning electron microscopy, and high-performance liquid chromatography with diode array detection. As a result, the plant structure of the fabric of products (presumably nettle fabric) and the composition of decoration dyes and pigments were determined.

The applicability of N,N -substituted bispidines as ligands of metal complex catalysts for the ethynylation reaction was demonstrated on the addition of phenylacetylene to 4-fluorobenzaldehyde. It was shown that the N,N -myrtenyl-substituted bispidinone led to a slight enantioselectivity in the formation of the corresponding propargyl alcohols.

The paper presents the generalizing results of a long-term study (1994-2020) of the behaviour of persistent organic pollutants (POPs) in the unique Baikal-Selenga lake-river ecosystem in Russia and Mongolia. The research started in 1993 on the initiative of V. A. Koptyug by the staff of the Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS and the Baikal Institute of Nature Management SB RAS within the framework of Russian and international field work missions. As a result of the analysis of the data obtained by means of gas chromatography-mass spectrometry, some regularities of the entry, distribution and accumulation of POPs in various regions of the Baikal-Selenga aquatic ecosystem, which is the largest lake-river system in Inner Asia, were revealed. Detailed data on the content, distribution and profiles of organochlorine pesticides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons in surface waters, bottom sediments and biota have been obtained. The studies were carried out over the entire territory of the Baikal-Selenga ecosystem: Lake Baikal, the Selenga River delta, the Selenga River basin at the territories of Russia and Mongolia, including industrial areas and specially protected natural areas. The data obtained are an assessment of the current ecological state of the Baikal-Selenga region and can serve as a basis for identifying anthropogenic impact on the environment and public health with an assessment of environmental risk. These data can be used to develop approaches for environmental quality management and rational use of natural resources, conservation of unique biodiversity and sustainable development of the Baikal region territory and can be considered as an element of the implementation of the Stockholm Convention on POPs.

To date, compounds having an adamantane moiety have found wide application in the pharmaceutical industry. Despite the fact that most biologically active adamantyl-bearing derivatives contain substituents in the first position of the adamantane molecule, some derivatives with substituents in the second position have also shown valuable pharmacological properties. While 1-adamantanecarboxylic acid is an inexpensive and commercially available reagent, its 2-substituted analogue is substantially less available, and therefore, the development and optimization of approaches to the synthesis of 2-adamantanecarboxylic acid are of great importance. In this work, a three-stage method for the synthesis of 2-adamantanecarboxylic acid has been optimized, based on the Corey-Chaykovsky reaction of 2-adamantanone with trimethylsulphoxonium iodide in the presence of potassium hydroxide, followed by acid-catalyzed opening of the oxirane ring and oxidation of aldehyde 9 to the target carboxylic acid. The total yield of the target product is 70 %.

The dianion generated by the reduction of terephthalonitrile with sodium in liquid ammonia arylates di- and trifluorobenzonitrites replacing the ortho - and para -fluorine atoms, as well as the para -hydrogen atom, with the para -cyanophenyl fragment. The orientation of the interaction, the structure of the resulting fluorinated 4,4'- and 2,4'-dicyanodiphenyls, and reaction productivity are determined by the location and number of fluorine atoms in the starting benzonitrile.

1-Alkoxy-3-imidazolines derived from stable nitroxide radicals, as well as nitroxide radicals themselves, bearing the 2-pyridyl substituent in position 2, under mild conditions undergo acid-catalyzed rearrangement with the fragmentation of the imidazoline ring and the formation of imidazo[1,5-a]pyridine. This rearrangement does not occur in superacid media due to the protective protonation of the nitrogen atom of the pyridyl substituent.

For the analysis of fluorine in difficult-to-burn and complex organofluorine compounds, special additives have been developed to ensure complete decomposition of the substances. Using a spectrophotometric technique based on the formation of а fluoride complex with lanthanum alizarin complexone, various organofluorine compounds have been analyzed with fluorine content of 1.5 to 70 % containing heteroelements in their structures: sulphur, chlorine, bromine, phosphorus, boron, selenium, tellurium in various combinations, as well as metals. The error of determination was established to be not higher than 0.5 abs. %

The effect of leuzea (Rhaponticum carthamoides) and cranberry (Vaccinium oxycoccus) meal extracts composition at a dose of (70 + 500) mg/kg, as well as individual active substances (ecdisten and ursolic acid) in equivalent doses, on the biochemical parameters of physical endurance (lactate, glucose) in the forced swim test on CD-1 male mice is investigated. It has been established that the developed composition exhibits pharmacological effects similar to those of the individual active substances promoting a decrease in the concentration of glucose (in blood) and lactate (in blood and in muscles).

The formation of a complex of magnesium and 4-ethylterpiridyl-(N-tert-butyl-N-(1-diethylphosphone-2,2-dimethylpropyl))-nitroxide alkoxyamine (SG1-tpy) was investigated by means of NMR spectroscopy. The stoichiometry of the complex was determined by constructing the Job’s plot. The homolysis rate constant of the alkoxyamine used was determined by means of EPR spectroscopy, and the activation energy was estimated. Polystyrene was obtained by radical controlled polymerization, and its molecular weight characteristics were studied by gel-permeation chromatography. When magnesium trifluoroacetate is added to the polymer solution, the molecular weight of the polymer increases, which indicates the formation of the complex. Polystyrene was also synthesized using the complex form of the initiator. It is shown that all the obtained polymers are narrowly dispersed, polydispersity is less than 1.5.

Copolymer of 2-(4-acryloylpiperazin-1-yl)methyl)-9H-thioxanthen-9-one and methyl methacrylate was synthesized by radical polymerization. This copolymer has high molecular weight characteristics and is capable of forming long-lived anion radical states of the pendant thioxanthenone groups during electrochemical reduction. Using a combination of electrochemical and optical methods, it has been shown that the electronic states of the pendant groups are located within the band gap of methyl methacrylate and may promote the Frenkel mechanism of conductivity in dielectric thin films used in resistive memory devices.

Mass spectrometric characteristics of N-alkyl-4-nitro-1,2,3-triazoles were investigated using a gas chromatograph with a quadrupole mass spectrometric detector in the mode of electron ionization (70 eV). The stability of the molecular ion was studied depending on the position, structure and nature of the alkyl substituent at the endocyclic nitrogen atoms of nitrotriazole heterocycle. N2-alkyl-4-nitro-1,2,3-triazoles were found to have the highest stability and molecular ion intensity, independently of the alkyl substituent in the structure of the compound. The pathways of molecular ion fragmentation are proposed for the compounds under consideration, and characteristic ions are identified. Molecular ion fragmentation in N-alkyl-4-nitro-1,2,3-triazoles was discovered to start with the elimination of the exocyclic NO₂ group, followed by detachment of the respective alkyl substituent and generation of the cation radical of 1,2,3-triazole. Fragmentation of non-substituted cation radical of 1,2,3-triazole proceeds through characteristic detachment of N atom or neutral molecules N₂ and HCN. In turn, the ionic decay of bulky alkyl substituents (cyclohexyl and benzyl radicals) leads to a group of characteristic ions with high relative intensity. In general, the findings demonstrate that mass spectrometry can be efficiently used for robust identification of structural isomerism ( N1-, N2- and N3-isomers) of alkyl-4-nitro-1,2,3-triazoles and the products of their decomposition.

Vitrinite concentrates of coal at different stages of metamorphism are studied by means of scanning electron microscopy and X-ray diffraction analysis. The results show that the cleaves and fractures on the surface of maceral particles have a structure characteristic of vitreous amorphous bodies for the whole metamosphism series. An increase in metamorphism degree is accompanied by an increase in the electrical conductivity of vitrinite particles and a decrease in the reflectivity with respect to electrons due to a decrease in the content of oxygen atoms. It is shown by means of X-ray diffraction that vitrinites have a turbostratic carbon structure, formed by polyarene layers with the interlayer spacing (d₀₀₂) decreasing from 3.64 to 3.50 Å with an increase in metamorphism stage, at the same time an increase in the dimensions of structured vitrinite fragments - height (L_c) andd width (L_a) of arene layer packets - is observed. A linear dependence is revealed between d₀₀₂ and vitrinite reflectance.