Threefold Excess Research Articles

Parallel Minisci Reaction of gem-Difluorocycloalkyl Building Blocks.

Parallel Minisci reactions of nonfluorinated and gem-difluorinated C4-C7 cycloalkyl building blocks (trifluoroborates and carboxylic acids) with a series of electron-deficient heterocycles were studied. A comparison of the reaction's outcome revealed better product yields in the case of carboxylic acids as the radical precursors in most cases, albeit these reagents were used with three-fold excess under optimized conditions. The nature of the heterocyclic core was found to be important for successful incorporation of the cycloalkyl fragment. The impact of the CF2 moiety on the oxidation potential of fluorinated cycloalkyl trifluoroborates and the reaction outcome, in general, was also evaluated.

Особенности микокомплекса ризосферы донника лекарственного

In the conditions of a small-scale experiment on a natural infectious background (Belgorod, Russia), a threefold excess of the CFU values of the rhizosphere of the Melilotus officinalis was revealed in comparison with the fallow soil, but the abundance of typical species in the rhizosphere and control was 63% and 77%, respectively. The Jacquard coefficient proved the high similarity of mycocomplexes of the rhizosphere of M. officinalis with the control (33%). The core of the rhizosphere microcomplex of sweet clover is the species Trichoderma lignorum. It is shown that the cultivation of sweet clover contributes to the improvement of the soil by reducing the proportion of pathogenic and allergenic species of micromycetes. The loss of the green mass of the sweet clover from septoria was recorded at the level of 20%.

Expedient synthesis of 1,2,4-triazinyl substituted benzo[c]coumarins via double oxidation strategy

Herein, we report a convenient one-pot synthesis of 1,2,4-triazinyl derivatives of benzocoumarins. The proposed approach consists in the nucleophilic addition of tetrahydrobenzo annulated dimethoxycoumarin to 1,2,4-triazines followed by double oxidation of both dihydrotriazine and tetrahydrobenzo groups with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The nucleophilic addition of the dimethoxycoumarin to 1,2,4-triazines was carried out in the presence of three-fold excess of methanesulfonic acid in DCM at room temperature and take place between positions 4 and 5 of coumarin and 1,2,4-triazine, respectively. The double oxidation step was achieved with 3.6 equivalent of DDQ. Selective oxidation of dihydrotriazine moiety, without affecting the tetrahydrobenzo fragment, was achieved using 1.2 equivalent of tetrachlorobenzoquinone (TCQ). The differences in the oxidation with TCQ and DDQ appear to be related to the higher oxidative potential of DDQ in contrast to TCQ. The advantages of the method are the elimination of the use of transition metals, the availability of starting materials, and the simplicity of the procedure. The proposed approach provides a two-step one-pot protocol for the synthesis of triazinyl benzocoumarins, precursors for the preparation of push-pull pyridinyl chromophore.

ANALYSIS OF EMERGENCY MODES OF TRACTION INDUCTION ELECTRIC DRIVE

The operation process of the traction asynchronous electric drive of the rolling stock may be accompanied by the occurrence of emergency modes, which are characterized by current overloads and may lead to damaging power electric circuits or mechanical part of the electric drive. Therefore, studying electromagnetic processes that occur in emergency modes of operation is relevant, in particular, for developing systems aimed at diagnosing and protecting traction equipment. Ukrainian and foreign studies of emergency modes in an asynchronous electric drive were analyzed. The most frequent causes of emergency modes are failures in static converters, therefore it is advisable to conduct an analysis of electromagnetic processes specifically in autonomous inverters. Using Matlab/Simulink software environment a simulation model of the vector control system of the traction asynchronous electric drive with spatial vector pulse width modulation was developed, and the short-circuit modes of the power switch of the autonomous voltage inverter and the disappearance of the supply voltage were simulated. The oscillograms of electromagnetic processes in these modes were shown and compared with the nominal mode of operation. The simulation results show that the analyzed emergency modes, even with a short duration of less than 0.5 s, can lead to significant damage to the electric drive. Both cases lead to significant current overloads: in the case of a short circuit of the power switch, a three-fold excess of the phase current is observed, during recovery after a supply voltage failure, the phase currents increase to the starting level, as well as an almost instantaneous increase in the supply voltage on the input filter capacitor occurs. The Fourier analysis of the phase A current in the above emergency modes shows an increase in the coefficient of nonlinear distortions by 65 %, a decrease in the amplitude of the main harmonic to 60 %, and the appearance of a significant number of subharmonics. In the case of a short circuit, the amplitudes of the subharmonics even exceed the fundamental harmonic. In addition, the process of returning from the emergency mode to normal at the first moment of time was characterized by a reduced moment of resistance (20 % of the nominal), and then by an exit to the nominal parameters.

ALKYLBENZENESULFONIC ACID AS A REAGENT FOR FLOTATION EXTRACTION OF LANTHANUM (III), SAMARIUM (III) AND TERBIUM (III) IONS

The anionogenic surfactant alkylbenzenesulfonic acid is proposed as a collector for ionic flotation of rare-earth elements. Stability of foams at various concentrations of alkylbenzenesulfonic acid has been preliminarily studied. Shaking 5 mL of solutions with 0.1 or 0.01 mol/L reagent containing for 30 s produces 15 mL of foam. This volume persists for up to 10 min, after which it degrades within 1.5 h. At the alkylbenzenesulfonic acid concentration of 0.001 mol/L, close to the critical micelle concentration, the volume of the formed foam is half as much and its destruction is slower. Further reduction of the alkylbenzenesulfonic acid content leads to the formation of scanty and unstable foams. The possibility of flotation recovery of three-charged ions of rare earth elements (lanthanum, samarium and terbium) with alkylbenzenesulfonic acid from their aqueous solutions with 0.001 mol/L concentration was considered. The influence of the molar ratio of lanthanide ions and alkylbenzenesulfonic acid, as well as the flotation time on the qualitative and quantitative characteristics of the flotation process has been studied. Determination of rare earth elements recovery rate was carried out by their residual content in the solution after flotation. Alkylbenzenesulfonic acid predominantly acts as a precipitant in the studied processes. The surfactant ions remaining in the solution contribute to foaming. During flotation for 5 minutes the maximum recovery of lanthanum (III) was 97.21% at the metal vs. reagent ratio 1:3.5. For samarium (III) and terbium (III) a threefold excess of alkylbenzenesulfonic acid is optimal. The extraction of terbium (III) in this case reaches 91.72% for 5 min, samarium (III) – 86.84% for 10 min. For citation: Zabolotnykh S.A., Denisova S.A., Nagovitsyn R.R., Vaulina V.N. Alkylbenzenesulfonic acid as a reagent for flotation extraction of lanthanum (III), samarium (III) and terbium (III) ions. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 3. P. 45-51. DOI: 10.6060/ivkkt.20236603.6651.

COMPARATIVE ANALYSIS OF THE ECONOMIC DEVELOPMENT OF THE CIS COUNTRIES IN 1990-2021

The results of a comparative analysis show that by 1990 the CIS countries are divided into four groups in terms of economic growth rates: with very high (Turkmenistan and Uzbekistan), high (Azerbaijan, Kazakhstan, Armenia and Belarus), medium (Tajikistan, Kyrgyzstan and Russia) and low (Georgia, Moldova, Ukraine) at a pace. At the same time, Kazakhstan is characterized by a more even progressive development. Due to lower prices in Tajikistan, Uzbekistan, and Kyrgyzstan (21-24% of the US price level), PPP USD GDP data for these countries is 4-5 times larger than foreign exchange GDP data. In Turkmenistan, the highest price level (47% of the US price level) provides more than a doubling of GDP in US dollars. In other countries, the price level is at the level of 30-37% of the price level in the USA, providing about a threefold excess of GDP data at PPP in comparison with GDP data at exchange rates.

Mechanically stimulated reactions in metal–oxide (carbide) systems

The processes of mechanochemical reduction of oxides of iron, nickel, and copper with aluminum with a stoichio metric ratio of components and in mixtures with a two-, three-, and four-fold excess of the aluminum content over the stoichiometric, as well as in the presence of an excess of oxide-forming metal and solid solutions of aluminum in iron and copper, were studied by the Mössbauer and IR spectroscopy, X-ray diffraction analysis, including the use of synchrotron radiation, and electron microscopy. The conditions for formation of metals modified with aluminum oxide (iron, nickel, copper) and their monoaluminides are determined. High aluminum content aluminides are formed at a three-fold excess of aluminum, and at a four-fold excess, a mechanochemical reduction of oxides does not occur. The preferred method for modifying metals with alumina is the mechanochemical reduction of oxides with a solid solution of aluminum in the oxideforming metal. Mechanochemical interaction in the high-energy Hf–C system in the presence of 20, 30, and 50 wt. % copper leads to the formation of hafnium carbide; and with an increase in the copper content, the crystallite size decreases.

5-{[4-(Di-methyl-amino)-phen-yl]ethyn-yl}pyrimidine-1,2,3,5-tetra-fluoro-4,6-di-iodo-benzene (1/2).

The treatment of 5-{[4-(di-methyl-amino)-phen-yl]ethyn-yl}pyrimidine with a threefold excess of 1,2,3,5-tetra-fluoro-4,6-di-iodo-benzene in di-chloro-methane solution led to the formation of the unexpected 1:2 title co-crystal, C14H13N3·2CF4I2. In the extended structure, two unique C-I⋯N halogen bonds from one of the 1,2,3,5-tetra-fluoro-4,6-di-iodo-benzene mol-ecules to the pyrimidine N atoms of the 5-{[4-(di-methyl-amino)-phen-yl]ethyn-yl}pyrimidine mol-ecule generate [110] chains and layers of these chains are π-stacked along the a-axis direction. The second 1,2,3,5-tetra-fluoro-4,6-di-iodo-benzene mol-ecule resides in channels formed parallel to the a-axis direction between stacks of 5-{[4-(di-methyl-amino)-phen-yl]ethyn-yl}pyrimidine mol-ecules and inter-acts with them via C-I⋯π(alkyne) contacts.

Synthesis of 6-chloro(dichloro-, trichloro-)-methyl-3-R-6,7-dihydro-2H-[1,2,4]triazino[2,3-c]- quinazolin-2-ones and their modification in reactions with nucleophilic and non-nucleophilic bases

The synthesis of 6-chloro-(dichloro-, trichloro)methyl-3-R-6,7-dihydro-2H-[1,2,4]triazino[2,3-c]quinazolin-2-ones and their modification under the action of nucleophilic and/or basic reagents are described in this article. It was shown that 6-chloro-(dichloro-, trichloro)methyl-3-R-6,7-dihydro-2H-[1,2,4]triazino[2,3-c]quinazolin-2-ones can be prepared by cyclocondensation of 3-(aminophenyl)-6-R-1,2;4-triazine-5(2Н)-ones with chloro-(dichloro-)acetaldehyde or chloral hydrate. The reactivity of the synthesized compounds toward nucleophilic base morpholine and non-nucleophilic base diisopropylethylamine (DIPEA) under different conditions was studied. It was shown that the prepared compounds under the action of morpholine and/or DIPEA can be converted into the products of substitution, elimination or elimination followed by isomerization and substitution. Refluxing of 6-(chloromethyl)-3-R-6,7-dihydro-2Н-[1,2,4]triazino[2,3-с]quinazoline-2-ones with equimolar quantity of morpholine and 10% excess of DIPEA in ethylene glycol monoethyl ether (EGEE) yielded the products on N-alkylation. 6-(Morpholinomethyl)-3-R-2H-[1,2,4]triazino[2,3-с]quinazoline-2-ones were obtained by heating of 6-dichloromethyl-3-R-6,7-dihydro-2Н-[1,2,4]triazino[2,3-с]quinazoline-2-ones with five-fold excess of morpholine in EGEE. Reaction of 3-R-6-(trichloromethyl)-6,7-dihydro-2H-[1,2,4]triazino[2,3-с]quinazolin-2-ones with three-fold excess of DIPEA in EGEE yielded 3-R-2Н-[1,2,4]triazino[2,3-с]quinazoline-2-ones. The physicochemical and spectral characteristics of the prepared compounds were determined and discussed.

Complexation processes in “PbCl2-N2H4CS” aqueous solutions during deposition of lead sulphide films

In this study, we proposed a new approach to assessing the processes of complexation in aqueous solutions using the example of the interaction of lead chloride with thiourea. The goal of this study was the investigation of processes of complexation in “PbCl2-N2H4CS” aqueous solutions and determination of the regions of dominance of thiourea coordination compounds, which are precursors during the deposition of lead sulphide films.Based on the diagrams and cross section lines of equal fractions constructed in three-dimensional space, the regions of dominance of all complex forms existing in the studied solution were found. Such a graphic image is the most informative, since it allows selection of the concentration ranges of the predominance of certain coordination compounds, especially thiourea complexes, which are precursors during the deposition of lead sulphide films. It was shown that an increase in the concentration of N2H4CS led to an increase in the total fraction of thiourea complexes: for a twofold excess of N2H4CS its fraction was 0.25, for a threefold excess it was 0.35, for a fourfold excess it was 0.5, for a fivefold excess it was 0.7.

New Aspects of Complex Formation in the Gadolinium(III)–Citric Acid System in Aqueous Solution

ABSTRACT The complexation of gadolinium(III) with citric acid in aqueous solutions was studied by pH-metric titration, proton magnetic relaxation, and mathematic simulation in the pH range 2.0–10 at [Gd3+]: [H4Cit] = 1:1, 1:2, 1:3 ([Gd3+] = 1.3, 2.6, 5.0, 10.0, and 20.0 mmol L−1). In the process of simulation, the equilibrium composition, a model obtained from previously known works and including mono- and bis-citrate complexes of gadolinium(III) was taken as a basis. In this work, it is shown that a satisfactory description of the experimental data set of two independent physico-chemical methods is achieved only with the additional inclusion of citrate complexes of gadolinium(III) with higher degree of protonation and some new polynuclear complexes. The complex [GdH4Cit]3+ with the molecular form of the citrate ligand, and the polynuclear complexes [Gd2(HCit)2]°, [Gd2Cit2]2-, [Gd6(OH)2Cit6]8-, [Gd6(OH)3Cit6]9- were first detected at the molar ratio of 1:1. At two- and three-fold excess of citric acid, mononuclear bis- and tris-citrate complexes with different degrees of protonation were found, and binuclear tetrakis- and hexakis-citrate complexes [Gd2(HCit)Cit3]9-and [Gd2(HCit)4Cit2]14- at the pH > 7.5. On the example of this manuscript, the importance of applying the NMR relaxation method for identifying polynuclear complexation in systems containing paramagnetic ions is shown.

Wertheim’s Operation. Problems and achievments

Aim. Analysis of modern modification of Wertheim’s operation and its results in Bukovina region for last 10 years.Methods. Analysis of literature in internet. Data about morbidity and mortality of cancer colli uteri in Chernivtsi Oncology Center.Results. An original description of the technique of radical hysterectomy for cervical cancer by Wertheim is presented. Modifications of the Wertheim operation with various classifications of interventions are considered. In first class of this classification are included extra fascial hysterectomies without resection of tissues, lymph nodules and fascia of pelvis which directly contradicts the principles of Wertheim's operation. The results of radical laparoscopic hysterectomy for cervical cancer are discussed. In 2019 trials, there was an almost three-fold excess of relapses after laparoscopic hysterectomies compared to open operations. The issues of the epidemiology of cervical cancer in Ukraine and Bukovina are considered. The incidence of cervical cancer in the Chernivtsi region was about 70 patients per year, or 8.4 per 100,000 population (data from 2016-2018). Cervical cancer mortality was from 40 to 43 people annually or 4.3-4.7 per 100,000 population. Wertheim’s operation is performed annually in 26-34 women and is practically not accompanied by complications and mortality.Conclusion. Wertheim’s operation is safe and unique method for treatment of cervical cancer.

Rearrangement of spiroderivatives of 1,3-benzo(naphtho)dioxin-4(1)-ones as a new method of synthesis of xanthene bromo derivatives

We have proposed a method for the synthesis of previously unknown bromo xanthenes using the reagent PBr3/DMF as a rearrangement initiator. Bromo derivatives of xanthenes in the form of organic perchlorates were prepared by reacting the corresponding benzo(naphtho)dioxin-4(1)-ones with a three-fold excess of Vilsmeier-Haack PBr3/DMF reagent at 1100C for 2 hours, followed by the addition of sodium perchlorate. The conditions for the synthesis of formyl derivatives of xanthenes under conditions of acid hydrolysis were selected. The structure of the compounds was confirmed by 1H and 13C NMR spectral data and mass spectrometry. Preliminary studies showed that it is possible to selectively replace the dimethylamino group and the bromine atom with various nucleophiles in bromo derivatives of xanthenes, which opens up wide possibilities for the synthesis of low-molecular building blocks and dyes.

Fourier-transform infrared spectroscopy in a comparative study of animal and plant proteins

The method of infrared attenuated total reflection spectroscopy was used to compare proteins (sarcoplasmic, myofibrillar, stroma) contained in the pork muscle tissue, globular proteins obtained from industrially crushed flax seeds, as well as protein-polysaccharide complexes extracted from husked seed coats and whole seeds. Protein components were isolated from saline solutions by precipitation with a threefold excess of 96% ethanol and 5% trichloroacetic acid, as well as by isoelectric precipitation at pH = 4.2. It is shown that the use of different anatomical parts (core and seed coat), including crushed or whole forms and flax seed meal, under varying conditions of pre-treatment, extraction and isolation allow biologically active protein-containing products to be obtained. Such products - protein concentrates, peptide polysaccharides and protein-lipid-polysaccharide complexes with a variable composition and ratio of components - are valuable raw materials for the food industry, medicine, pharmacopoeia and cosmetology. A comparative study of the kinetics of air drying of crude plant and animal globular proteins at 20°C showed these proteins to be similar in terms of extreme changes in the spectra of light absorption curves and the intensity of the main characteristic bands upon moisture removal. Temperature changes, affecting the general appearance of light absorption spectra, lead to deformation of the Amide-I band, which carries information about the protein structure. Deformational changes may be promoted not only by differentiation of globular proteins (albumins and globulins), but also by packing of their polypeptide chains during reconstruction or formation of a new secondary structure destroyed as a result of various mechanical and chemical interventions. According to the obtained data, elevated temperatures have a significant effect on the structural transformations of both protein concentrates and protein-polysaccharide complexes, regardless of their nature.

STRUCTURE AND LUMINESCENT PROPERTIES OF EUROPIUM(III) COORDINATION POLYMERS WITH THIOPHENE LIGANDS

Three new metal-organic frameworks based on sulfur-containing 2,2′-bithiophene-5,5′-dicarboxylic acid (H2btdc) and thieno[3,2-b]thiophene-2,5-dicarboxylic acid (H2ttdc) are obtained. Their compositions are: [Eu(DMF)2(NO3)(btdc)]·DMF (1), [Eu2(H2O)2(DMF)(btdc)3]·H2O·3DMF (2), and [Eu2(DMF)4(ttdc)3]· 4DMF (3). Structures of the compounds are determined by single crystal X-ray diffraction: 1 is a layered compound whereas 2 and 3 have a three-dimensional framework with channel-like pores. The specific volume of cavities in the structures of 1-3 varies from 34% to 37%. Compounds 2 and 3 are characterized by IR spectroscopy, elemental and thermogravimetric analyses. The luminescent properties of solid samples of 3 are studied and a luminescent response (a threefold excess of the luminescence quantum yield of the 3⊃cyclohexane adduct in comparison with 3⊃benzene) is revealed.

The Free-Radical Nature of Nitric Oxide Molecules as a Determinant of their Conversion to Nitrosonium Cations in Living Systems

This paper presents new results that confirm our previous inference that the binuclear form of biologically active dinitrosyl iron complexes (B-DNICs) with thiol-containing ligands (glutathione or N-acetyl-L-cysteine) may act as a donor of nitrosonium cations, which are responsible for S-nitrosothiol formation during B-DNIC decomposition in acid solutions under both aerobic and anaerobic conditions. The presence of nitrosonium cations within B-DNICs is determined by the dispropoportionation reaction of free-radical nitric oxide (NO) molecules while binding to Fe2+ cations (two molecules per one ion) during B-DNIC synthesis. When thiolic ligands are oxidized in DNICs or inactivated by thiol-specific reagents, the nitrosonium cations released during decomposition of these DNICs at neutral pH values are hydrolyzed and transformed to nitrite anions. A similar transformation occurs when mononuclear DNICs (M-DNICs) with nonthiolic ligands are decomposed at neutral pH values. It has been found that S-nitrosothiol formation in the decomposition of B-DNICs with thiolic ligands at acidic pH values can be inhibited by the presence of a two to threefold excess of free thiol molecules (outside the B-DNIC) with regard to the B-DNIC level. This inhibition is due to the reduction of nitrosonium cations induced by free thiol molecules and catalyzed by iron ions. The NO molecules that result from the reduction are released from the DNICs. Thus, both forms of DNICs, M and B, that form in living systems can act not only as donors of NO, which is now recognized as one of the universal regulators of metabolic processes, but also as donors of nitrosonium cations, which initiate S-nitrosation of low- and high-molecular-weight (protein-bound) thiols.

Degradation of the cellulosic key chromophore 2,5-dihydroxy-[1,4]-benzoquinone (DHBQ) under conditions of chlorine dioxide pulp bleaching: formation of rhodizonate as secondary chromophore\u2014a combined experimental and theoretical study

2,5-Dihydroxy-[1,4]-benzoquinone (DHBQ, 1) is the most prominent representative of cellulosic key chromophores, which occur almost ubiquitously in all types of aged cellulosics. The degradation of DHBQ by chlorine dioxide under conditions of industrial pulp bleaching (“D stage”) was studied, i.e. in moderately acidic medium (pH 3) at temperatures between 50 and 90 °C. The degradation in the presence of excess ClO2 generates rhodizonic acid (RhA, 5,6-dihydroxycyclohex-5-ene-1,2,3,4-tetrone, 2) as a secondary chromophore which is even more stable and more potent as a chromophore than the starting DHBQ, especially in the form of its salts. At least a threefold ClO2 excess is needed for complete DHBQ consumption. The reaction from DHBQ to RhA involves pentahydroxybenzene (PHB, I) as an intermediate which is either readily further oxidized to RhA by excess ClO2 or slowly reconverted to DHBQ in the absence of ClO2. The RhA yield after 30 min reaction time had a maximum of 83% at a DHBQ/ClO2 molar ratio of 1:5, and decreased with increasing ClO2 charge, reaching 38% at a DHBQ/ClO2 ratio of 1:8 and above. Degradation of DHBQ by ClO2 is 42 times faster than that of RhA (50 °C, pH 3). RhA is present in aqueous medium in the form of its dihydrate, 2,3,5,5,6,6-hexahydroxycyclohex-2-ene-1,4-dione, which contains two pairs of geminal diols at C-5 and C-6. At pH 5 and above it forms an aromatic C6O62− dianion, so that the RhA salts are very stable. These salts are intensively colored, not only the ones with transition metal cations, but also those with monovalent (Na+, K+) and especially divalent (Ca2+, Mg2+) main group metals, and usually have very low solubility so that they precipitate on the pulp fibers. It was demonstrated that the inferior ClO2-bleachability of some pulps is due to the conversion of DHBQ into colored RhA and its respective salts.Graphic abstract

Alkyl-substituted 1,1'-Dihydroxy-2,2'bimidazoles: Reactions with Methyl Iodide and Trimethyl Phosphite

The alkylation of alkyl-substituted 1,1'-dihydroxy-2,2'-biimidazoles with an equimolar amount of methyl iodide occurs exclusively at the imidazole nitrogen atom, while with a three-fold excess of methyl iodide, both the imidazole nitrogen atom and two hydroxy groups are involved in alkylation. The reaction of 1,1'-dihydroxy-2,2'-biimidazoles with P(OMe)3 forms the corresponding 2,2'-biimidazoles.

АНАЛИЗ СТРУКТУРЫ МЕЖРЕГИОНАЛЬНОЙ ТОРГОВЛИ РЕСПУБЛИКИ БУРЯТИЯ

The article describes the commodity structure and geography of interregional trade in the Republic of Buryatia. In particular, the practical importance of the study of interregional trade is justified and the main problems of such studies in the domestic practice of research are described. In addition, the distinctive features, sources and structure of the statistical data used in the study are disclosed. The results of the analysis show the structure of interregional trade in the Republic of Buryatia in the context of trade directions (import-internal-export) and by product groups (consumer goods and industrial and technical goods). These results are linked to the structure of the economy and the special territorial position of the republic. In particular, the more than nine-fold superiority of import volumes over export volumes is due to poorly developed manufacturing and mining industries. It is established that a total of 67 regions of Russia supply various goods to the republic. The key positions from the list of imported goods are occupied by various types of fuel, products of metallurgical production, passenger cars and alcoholic beverages. The almost three-fold excess of the volume of products consumed within the republic over the volume of exports is due to the significant distance from the centers of the main interregional agglomerations and the territorial sparseness of the surrounding area. Despite the relatively small export volumes, deliveries from the Republic of Buryatia are carried out in 35 regions of Russia. This fact is associated with the availability of the main transport arteries of the country – the Trans-Siberian Railway and the federal highway P258 "Baikal". The key positions from the list of goods exported from the republic are occupied by food industry products and various non-metallic mineral products. The analysis of the geography of interregional trade revealed the decline in its intensity (import-export turnover, mln. rub.) as you move away from the republic in a westerly direction, as well as its concentration with the regions located in close proximity to the main transport arteries of the country. The western regions are mostly net suppliers of the republic in terms of import and export volumes, while the majority of the eastern regions are net consumers.

An Aminopyrrolidinyl Phosphonates—A New Class of Antibiotics: Facile Synthesis and Predicted Biological Activity

A novel class of aminopyrrolidinyl phosphonates was synthesized in 74% - 80% isolated yield by the addition of three-fold excess of primary amines to diethyl 4-chloro-1-butynylphosphonates. The reaction was carried out at room temperature and in the absence of solvent or catalyst to give solely compounds which showed predicted biological activity based on PASS program. Some of the synthesized derivatives of antibiotics exhibit properties for the treatment of stroke, the treatment of acute neurological disorders, and can also be acetyl esterase inhibitors.