bluuebunny/crossref_metadata_2025 huggingface dataset:
Representation of the Green’s Function of the Dirichlet Problem for the Polyharmonic Equation in the Ball
Authors: Karachik V. V
Published: April 2024

We define the elementary solution of the polyharmonic equation, with the help of which an explicit representation of the Green’s function of the Dirichlet problem for the polyharmonic equation in the unit ball is given for all space dimensions except for some finite set. On the basis of the obtained Green’s function, the solution of the homogeneous Dirichlet problem in the unit ball is constructed. As an example, an explicit form of the solution of the homogeneous Dirichlet problem for the inhomogeneous polyharmonic equation with the simplest polynomial right-hand side is found.
Interior of the Integral of a Set-Valued Mapping and Problems with a Linear Control System
Authors: Balashov M. V
Published: April 2024

The dependence of the radius of a ball centered at zero inscribed in the values of the integral of a set-valued mapping on the upper integration limit is studied. For some types of integrals, exact asymptotics of the radius with respect to the upper limit are found when the upper limit tends to zero. Examples of finding this radius are considered. The results obtained are used to derive new sufficient conditions for the uniformly continuous dependence of the minimum time and solution-point in the linear minimum time control problem on the initial data. We also consider applications in some algorithms with a reachability set of a linear control system
Optimal Feedback in a Linear–Quadratic Optimal Control Problem for a Fractional-Order System
Authors: Gomoyunov M. I , Lukoyanov N. Yu
Published: April 2024

For a dynamical system described by a linear differential equation with a Caputo fractional derivative, we consider an optimal control problem of minimizing a quadratic terminal–integral performance functional. We propose and justify the construction of optimal feedback (optimal control synthesis) that generates the corresponding optimal control for any initial state of the system.
On the Existence of a Solution of a Boundary Value Problem on a Graph for a Nonlinear Equation of the Fourth Order
Authors: Kulaev R. Ch. , Urtaeva A. A.
Published: April 2024

A fourth-order nonlinear differential equation on a network that is a model of a system of Euler–Bernoulli rods is considered. Based on the monotone iteration method, the existence of a solution of a boundary value problem on a graph for this equation is established using the positiveness of the Green’s function and the maximum principle for the corresponding linear differential equation. An example is given to illustrate the results.
Existence of Two Solutions of the Inverse Problem for a Mathematical Model of Sorption Dynamics
Authors: Denisov A. M , Duntsin' Chzhu
Published: April 2024

The inverse problem for a nonlinear mathematical model of sorption dynamics with an unknown variable kinetic coefficient is considered. A theorem on the existence of two solutions of the inverse problem is proved, and an iterative method for solving it is justified. An example of the application of the proposed method to the numerical solution of the inverse problem is given.
On Nonlinear Boundary Value Problems for Differential Inclusions
Authors: Arutyunov A. V. , Zhukovskaya Z. T. , Zhukovskiy S. E.
Published: April 2024

We consider autonomous differential inclusions with nonlinear boundary conditions. Sufficient conditions for the existence of solutions in the class of absolutely continuous functions are obtained for these inclusions. It is shown that the corresponding existence theorem applies to the Cauchy problem and the antiperiodic boundary value problem. The result is used to derive a new mean value inequality for continuously differentiable functions.
On Solutions of a System of Nonlinear Integral Equations of Convolution Type on the Entire Real Line
Authors: Davydov A. A. , Khachatryan Kh. A. , Petrosyan A. S.
Published: April 2024

We consider a special system of integral equations of convolution type with a monotone convex nonlinearity naturally arising when searching for stationary or limit states in various dynamic models of applied nature, for example, in models of the spread of epidemics, and prove theorems stating the existence or absence of a nontrivial bounded solution with limits at +@ depending on the values of these limits and on the structure of the matrix kernel of the system. We also study the uniqueness of such a solution assuming that it exists. Specific examples of systems whose parameters satisfy the conditions stated in our theorems are given.
On the Variation of the Nonlinearity Parameter in the “Super-Twisting” Algorithm
Authors: Fomichev V. V. , Vysotskiy A. O.
Published: April 2024

We study the stability of a modified (with variation in the nonlinearity parameter) “super-twisting” algorithm. The analysis is based on majorizing the trajectories of the system with an arbitrary nonlinearity parameter by the trajectories of systems of the classical “super-twisting” algorithm. Stability conditions for the modified systems are obtained, as well as estimates for the size of the stability domain depending on system parameters
Interaction of polyfluorobenzocyclobutenes with oleum
Authors: Golokhvastova D. S , Zonov Ya. V. , Karpov V. M , Mezhenkova T. V
Published: April 2024

When perfluorinated 1-methyl- and 1-ethylbenzocyclobutenes, 2-methyl- and 2-ethylbenzocyclobutenones react with 20% oleum at 150°C, 3-perfluoroalkyl-4,5,6,7-tetrafluorophthalides and perfluoro-3hydroxy-3-alkylphthalides are formed in approximately equal proportions. Along with them, perfluoro-2hydroxy-2-methylbenzocyclobutenone was obtained in the reaction of perfluoro-2-methylbenzocyclobutenone with oleum at 100°C. Under the action of oleum, perfluoro-2-phenylbenzocyclobutenone forms perfluoro-2-benzoylbenzoic acid, and polyfluorobenzocyclobutene-1,2-diols form their cyclic sulfates.
Synthesis of (3S,4S)-4-Acetyl-3-(1R)-1-hydroxyethyl1-(4-methoxyphenyl)azetidin-2-one
Authors: Selezneva N. K , Galeeva A. M , Valiullina Z. R , Miftakhov M. S
Published: April 2024

The synthesis of the title compound from l-threonine with the participation of β-metallyl chloride amide in the N -alkylation step is described.
Synthesis of 4-(N4-methyl-5-aryl-1,2,4-triazole-5-ilmethylthio) cresoxyacetic acids and their sulfonic analogues of new potential PPARδ/β agonists
Authors: Minin D. V , Popkov S. V , Tsaplin G. V
Published: April 2024

A nine-stage scheme for the synthesis of 4-( N 4-methyl-5-aryl-1,2,4-triazole-5-ilmethylthio) cresoxyacetic acids of new potential PPARδ/β agonists based on substituted benzoic acids has been developed. Their sulfon-containing analogues were obtained from the intermediate esters of such acids.
Reaction mechanism of the formation of N-methyl-N-[2-(diphenylphosphoryl)-ethyl]amide of diphenylphosphorylacetic acid
Authors: Kuznetsova A. A , Chachkov D. V , Artyushin O. I , Bondarenko N. A , Vereshchagina Ya. A.
Published: April 2024

The reaction mechanism of the formation of N -methyl-substituted diphenylphosphorylacetic acid amide was studied by DFT. According to theoretical calculations, at the first stage, explicit allowance for the solvent makes it possible to reduce the activation energy of three elementary stages of the interaction of trichlorophosphine with diphenylphosphorylacetic acid; at the second stage, the interaction of diphenylphosphorylacetic acid chloride with a phosphoryl-containing amine proceeds in one elementary stage.
Synthesis and inhibitory activity of atorvastatin conjugate with a branched asialoglycoprotein receptor ligand with 3 N-acetyl-d-galactosamine residues
Authors: Maklakova S. Yu. , Mazhuga M. P , Lopukhov A. V , Gibadullina K. R , Klyachko N. L , Majouga A. G , Beloglazkina E. K
Published: April 2024

The novel atorvastatin conjugate was synthesized in a multi-step procedure using branched N -acetylgalactosamine ligand for asialoglycoprotein receptor targeting. The molar solubility of the obtained conjugate was 6.1±0.9 mM, which is almost 60 times higher than that of unmodified atorvastatin. The hydrolysis products of the conjugate demonstrated effective inhibition of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase.
Synthesis of new macrocyclic triperoxides
Authors: Makhmudiyarova N. N , Ishmukhametova I. R
Published: April 2024

An efficient method has been developed for the synthesis of dialkyl hexaoxadispiroalkanedicarboxylates by the recyclization reaction of heptaoxadispiroalkanes with alkyl malonates (malonic acid dimethyl ester, malonic acid diethyl ester, malonic acid diisopropyl ester) under the action of lanthanide catalysts.
Mannich reaction in the synthesis of azaperoxides
Authors: Makhmudiyarova N. N , Ishmukhametova I. R
Published: April 2024

The applicability of the Mannich reaction in the synthesis of new tetraoxazodispiroalkanes by a three-component reaction of primary arylamines with gem-dihydroperoxides and cyclohexanone with the participation of Sm(NO3)3 6H2O as a catalyst has been established.
Reactions of β-nitro-substituted 1H-benzo[f]chromenes and benzofurans with nucleophiles
Authors: Osipov D. V , Artyomenko A. A , Korzhenko K. S , Raschepkina D. A , Demidov O. P , Osyanin V. A
Published: April 2024

A series of 3-alkoxy-2-nitro-2,3-dihydro-1 H -benzo[ f ]chromenes as a mixture of cis - and trans -isomers was obtained in the reaction of 2-nitro-1 H -benzo[ f ]chromenes with alcohols. The reaction with secondary cyclic amines and 3-amino-5,5-dimethylcyclohex-2-en-1-one proceeds trans -diastereoselectively to form Michael adducts of benzochromane structure. Conjugated addition involving anilines leads to (2-hydroxy-1-naphthyl) methyl-substituted β-nitroenamines. The nucleophilic dearomatization of 3-nitrobenzofurans under the action of primary aromatic amines was shown to involve sequential aza- and retro-oxa-Michael reactions. This reaction illustrates the high propensity of 3-nitrobenzofurans to open the furan cycle.
Reaction of N-sulfinyltrifluoromethanesulfonamide with succinyl chloride
Authors: Tolstikova L. L , Sterkhova I. V , Shainyan B. A
Published: April 2024

N -Sulfinyltrifluoromethanesulfonamide reacts with succinyl chloride to form 1-[(trifluoromethyl)sulfonyl]pyrrolidine-2,5-dione in high yield. The structure of the product was proved by X-ray diffraction analysis. The product is opened with ethanol under mild conditions selectively at the C-N bond to form (1 E )-4-ethoxy-4oxo- N -[(trifluoromethyl)sulfonyl]butanimidic acid.
About acid catalysed acetonation reactions of d-ribose
Authors: Valiullina Z. R , Ivanova N. A , Shavaleeva G. A , Akhmetdinova N. P , Lobov A. N , Abdullin M. F , Miftakhov M. S
Published: April 2024

For comparative identification of side products of the cyanation reaction of the imidate donor with trimethylsilyl cyanide, the main compounds formed in the acetonation reactions of D-ribose catalyzed by H2SO4, p -TSA, CSA, and PPTS were synthesized and characterized. The structures of the latter were correctly refined by spectral methods using 2D technologies and high-resolution mass spectrometry.
Complex formation of halogen substituted tetraphenylporphyrins and Cd(II)-tetraphenylporphyrins with MnCl2 in DMF
Authors: Zvezdina S. V , Chizhova N. V , Mamardashvili N. Z
Published: April 2024

Reactions of complex formation of 5,10,15,20-tetra-(2,6-dichlorophenyl)porphyrin, 5,10,15,20-tetra-(2,6-difluorophenyl)porphyrin and metal exchange of their cadmium complexes with manganese chloride(II) in dimethylformamide were investigated. ortho -Substituted manganese complexes were synthesized by prolonged refluxing of the corresponding porphyrins with an excess of MnCl2 in dimethylformamide. Using the metal exchange reaction of Cd(II)-5,10,15,20-tetra-(2,6-dichlorophenyl)porphyrin and Cd(II)-5,10,15,20-tetra-(2,6-difluorophenyl) porphyrin, the corresponding Mn(III)-tetraphenylporphyrins were obtained. On the contrary, the coordination reactions of porphyrins substituted at the pyrrole and phenyl rings with manganese chloride in dimethylformamide proceed under mild conditions with the formation of complexes Mn(II)-2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetra-(2,6-dichlorophenyl)porphyrin [the compound oxidizes in air to a mixture of Mn(II) and Mn(III)-porphyrins] and Mn(II)-2,3,7,8,12,13,17,18-octachloro-5,10,15,20-tetra-(2,6-difluorophenyl)porphyrin. The synthesized compounds were identified using UV-Vis, 1H NMR spectroscopy and mass-spectrometry. Metal exchange reaction of ortho -substituted Cd(II)-porphyrins and complex formation of 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetra-(2,6-dichlorophenyl)porphyrin with manganese chloride in dimethylformamide were studied by the spectrophotometric method. The kinetic parameters of the reactions were calculated. A strong effect of β- and ortho -substitution on the reactions of complex formation and metal exchange of the studied compounds was found.
Synthesis of [(4-methyl-6-oxo-1,6-dihydropyrimidin2-yl)sulfanyl]acetamides
Authors: Shiryaev A. K , Gulyaeva A. M , Shiryaev V. A , Aristova U. M
Published: April 2024

The reaction of ethyl-[(4-methyl-6-oxo-1,6-dihydropyrimidin-2-yl)sulfanyl]acetate with aliphatic amines gives corresponding acetamides; the reaction with hydrazine hydrate and aniline leads to 2-hydrazinyl- and 2-anilinopyrimidine respectively.
Synthesis, antimicrobial and antinociceptive activity 4-substituted 5-hydroxy-5-(tricholoromethyl)dihydrofuran-2,3-diones
Authors: Myshkina O. A , Kharitonova S. S , Balandina S. Y , Makhmudov R. R , Lisovenko N. Y
Published: April 2024

As a result of the reaction of 5-substituted 4-trichloroacetylfuran-2,3-diones with aromatic amines, 4-substituted 5-hydroxy 5-(trichloromethyl)dihydrofuran-2,3-diones, were synthesized, which have antibacterial and antinociceptive activities.
Diastereoselective synthesis of 3-[2-chloro(bromo)phenyl]2-methyl-2-[(prop-2-in-1-yl)oxy]oxiranes and 5-[3-chloro(bromo)phenyl]-2,2,4-trimethyl-4-[(prop-2-in-1-yl)]1,3-dioxolane
Authors: Talybov G. M , Akhmedova N. Ya.
Published: April 2024

The interaction of halogen-substituted benzaldehydes with 3-(1-chloroethoxy)prop-1-yne leads to the formation of unsaturated ethers of 2-hydroxyoxirane. The formation of the latter was confirmed by the reaction of the latter with acetone in the presence of BF3·Et2O with the formation of substituted 1,3-dioxolanes.
Organosilicon derivatives based on 2-aminothiazolium cations
Authors: Yarosh N. O , Dorofeev I. A , Zhilitskaya L. V
Published: April 2024

The reactions of 2-aminothiazole and 2-aminobenzothiazole with (iodomethyl) derivatives of silanes in the absence of a base gave the previously unknown organosilicon salts and ionic liquids of 2-aminothiazole and 2-aminobenzothiazole. Structure of the obtained compounds was proved by NMR, and UV spectroscopy methods.
Synthesis and antitumor activity of N-acylhydrazones from betulin diacetate
Authors: Myasoyedova Yu. V. , Belyaeva E. R , Ishmuratova N. M , Ishmetova D. V , Vakhitov V. A , Ishmuratov G. Yu.
Published: April 2024

Eight new N -acylhydrazones were synthesized from betulin diacetate by its low-temperature ozonolysis to obtain 3β,3,28-diacetoxyoxy-20-oxo-29-norlupan and condensation of the latter with hydrazides of aliphatic and aromatic acids. Cytotoxic activity of the obtained compounds in relation to a number of tumor cells was studied in vitro . Derivatives obtained by condensation of 3β,3,28-diacetoxy-20-oxo-29-norlupan with hydrazides of salicylic, isonicotinic and nicotinic acids showed moderate activity against cell lines of human hepatocellular carcinoma HepG2, human colon cancer HTC-116, leukemia THP-1, acute T-cell leukemia Jurkat.
Functional derivatization of 3- and 5-substituted cyclooctenes
Authors: Adzhieva O. A , Finko A. V , Roenko A. V , Denisova Yu. I. , Kudryavtsev Y. V
Published: April 2024

New derivatives of cyclooctene with an ester group in the 3- and 5-positions have been synthesized in high yield. The structure of obtained compounds was confirmed by a complex of physicochemical methods. The products are of interest as monomers for the synthesis of hydrophilic and amphiphilic homo- and copolymers using ring-opening metathesis polymerization of olefins. Owing to the unsaturated backbone, such polymers can undergo further modification, including by the reaction of macromolecular cross-metathesis.
Direct synthesis of a new hybrid molecules based on isomerically pure 5Z,9Z-dienoic acids and monocarbonyl derivatives of curcuminoids
Authors: Islamov I. I , Yusupova A. V , Dyakonov V. A , Dzhemilev U. M
Published: April 2024

Synthesis of previously undescribed hybrid compounds based on monocarbonyl derivatives of curcumin and 5 Z ,9 Z -dienoic acids with yields of 61-67% was carried out for the first time. Unsaturated acids are synthesized using at the key stage of stereoselective reaction of intermolecular cross-cyclomagnesiation of aliphatic and O-containing 1,2-dienes catalyzed by Cp2TiCl2.
Novel reaction of sulfonyl azides with fosphine sulfides
Authors: Filimonov V. O , Ilkin V. G , Seliverstova E. A , Bakulev V. A
Published: April 2024

(4-Methoxyphenyl)di(pyrrolidin-1-yl)phosphine sulfides were synthesized by reaction of Lausson’s reagent with cyclic amines. It was shown for the first time that phosphine sulfides react with aryl sulfonylazides when boiled in 1,4-dioxane with the elimination of nitrogen and elemental sulfur molecules and the formation of previously undescribed dicycloaminophosphoranylidene sulfonamides.
2,2-dichlorovinulketones-based 5-chloro-3-styryl-1H-pyrazoles synthesis
Authors: Kobelevskaya V. A , Zinchenko S. V , Popov A. V
Published: April 2024

Condensation of 4,4-dichlorobut-3-en-2-one with aromatic aldehydes in the presence of catalytic amounts of sulfuric acid leads to the formation of 1,1-dichloro-5-(4-R-phenyl)penta-1,4-diene-3-ones. The reaction of 1,4-dien-3-ones with hydrazines proceeds chemo- and regioselectively under mild conditions with the formation of ( E )-1-methyl-3-styryl-5-chloro-1 H -pyrazoles with a yield reaching 81%. 4-Bromo-1,1-dichloro-5-(4-methoxyphenyl)penta-1,4-dien-3-one reacts with dimethylhydrazine to give 3-[1-bromo-2-(4-methoxyphenyl)vinyl]-5chloro-1-methyl-1 H -pyrazole, which in the presence of KF in DMSO at 120°C forms 1-methyl-3-[(4-methoxyphenyl)ethynyl]-5-chloro-1 H -pyrazole with 69% yield. The structure of the synthesized compounds has been confirmed using IR, NMR spectroscopies, mass spectrometry, and elemental analysis.
3-[(alkylsulfanyl)methyl]pentane-2,4-diones based synthesis of 4-({4-[(alkylsulfanyl)methyl]-3,5-dimethyl-1H-pyrazole1-yl}carbonyl)pyridines
Authors: Baeva L. A , Biktasheva L. F , Gataullin R. R , Nugumanov T. R
Published: April 2024

Heterocyclization of 3-[(alkylsulfanyl)methyl]pentane-2,4-diones with isonicotinic acid hydrazide in ethanol in the presence of catalytic amounts of hydrochloric acid without or under microwave activation leads to new 4-({4-[(alkylsulfanyl)methyl]-3,5-dimethyl-1 H -pyrazole-1-yl}carbonyl)pyridines. Under analogous conditions, 3-[(alkylsulfanyl)methyl]pentane-2,4-diones are converted to the corresponding 4-[(alkylsulfanyl)methyl]-3,5-dimethyl-1 H -pyrazoles.
Synergistic effects of cyclic ketals in fuel compositions and antibactrial agents
Authors: Vol'eva V. B , Ovsyannikova M. N , Pokholok T. V , Ryzhakova A. V
Published: April 2024

The synergistic effect of cyclic ketals in compositions with lower alcohols was first discovered in the study of the octane-raising effect of ketals additives to alcohol-containing gasolines. The use of model oxidation reactions of ketals and their structural analogs, benzdioxolanes, in proton-donor media made it possible to associate the mechanism of the synergistic effect with the formation of ketal-alcohol complexes with the properties of surfactants that form hydrated supramolecular structures around them. Inside them, more efficiently than in a bulk medium, hot fuel radicals are deactivated with a transfer from an explosive combustion mode to a stationary one. Such a structuring effect is of general importance for the functioning of ketals in hydrophobic-hydrophilic systems, including biological media. This conclusion is confirmed by the study of cyclic ketals activity in compositions with alcohols and carboxylic acids as antibacterial agents.
para-substituted anilines in reactions with tropyl salts and dibenzosuberenol
Authors: Akent'eva T. A , Zhakova S. N
Published: April 2024

The features of the interaction of para-substituted anilines with tropyl salts and dibenzosuberenol have been studied. By the interaction of para-substituted anilines with tropyl salts (perchlorate or tetrafluoroborate) in an ethanol or tetrahydrofuran medium, the corresponding azomethines were obtained instead of the expected ortho-tropylated anilines. The tropilidene cycle (1,3,5-cycloheptariene cycle) underwent benzilidene narrowing due to an increase in temperature during a chemical reaction. The structurally related tropilidene - dibenzosuberene cycle can be introduced into the ortho position of para-substituted anilines to form stable ortho products. Dibenzosuberenol in an acidic environment is able to interact with ethanol to form an ether.
Direct cross-dehydrogenative С–N-coupling of phenanthridine with 1H-benzotriazole
Authors: Akulov A. A , Pershin A. A , Kopchuk D. S , Varaksin M. V , Zyryanov G. V , Chupakhin O. N
Published: April 2024

An approach was developed for the direct C( sp 2)-H-functionalization of phenanthridine with a 1 H -benzotriazole residue, carried out in the presence of Selectfluor® reagent and leading to the formation of a C( sp 2)-N bond. The procedure described in this communication makes it possible to obtain α-(1 H -benzotriazol-1-yl)phenanthridine, which is a valuable synthon for further chemical transformations, in one step and using commercially available substrates and reagents.
Reaction of 4,6-di-tert-butyl-3-nitrocyclohex-3,5-diene1,2-dione with secondary amines
Authors: Ivakhnenko E. P. , Malay V. I. , Demidov O. P. , Minkin V. I.
Published: April 2024

Reaction of 4,6-di- tert -butyl-3-nitrocyclohexa-3,5-diene-1,2-dione with secondary amines (piperidine, morpholine, 1-methylpiperazine) in isopropanol leads to a mixture of products formed as a result of parallel reactions of Michael addition and ANRORC. The compounds obtained were characterized by 1H NMR, 13C NMR, IR spectroscopy, and elemental analysis. Molecular structure of 3-nitrocyclohexa-3-ene-1,2-dione and cyclopenta1,3-diene derivatives was established by X-ray diffraction analysis.
Interaction of Methylenecycloalkanes with BF3·THF Catalyzed by 2TiCl2
Authors: Tulyabaeva L. I. , Salakhutdinov R. R. , Tulyabaev A. R. , Tyumkina T. V. , Abdullin M. F.
Published: April 2024

The Cp2TiCl2-catalyzed interaction of methylenecycloalkanes with BF3·THF in tetrahydrofuran was carried out for the first time with the formation of target 1-fluoro-1-boraspirocarbocycles and also isomerization products of a starting monomer (1-methylcycloalk-1-enes). The structure of reaction products was elucidated using one(1H, 13C Dept, 11B, 19F) and two-dimensional (COSY, HSQC, HMBC) NMR spectroscopy, mass spectrometry combined with quantum-chemical calculations of 13C NMR chemical shifts.
An effective approach to the synthesis of 2-([5ʹ-aryl-2,2ʹ-bipyridine]-6-yl)-5-aryl-1,3,4-oxadiazoles
Authors: Valieva M. I. , Starnovskaya E. S. , Kopchuk D. S. , Sharafieva E. R. , Slovesnova N. V. , Kovalev I. S. , Nosova E. V. , Zyryanov G. V. , Chupakhin O. N.
Published: April 2024

A convenient synthetic approach to derivatives of 2-(2,2ʹ-bipyridin-6-yl)-1,3,4-oxadiazoles is proposed as a result of the preparation using the “1,2,4-triazine” methodology of esters of 5-aryl-2,2ʹ-bipyridine-6-carboxylic acids and the subsequent construction of the 1,3,4-oxadiazole cycle by to modification of the ester group.
Double acylation product in the snсl4-promoted reaction of 4,5-dichlorocyclopent-4-en-1,3-dione with 1,3,5-trimethoxybenzene
Authors: Egorov V. A. , Khasanova L. S. , Gimalova F. A. , Miftakhov M. S.
Published: April 2024

The interaction of 4,5-dichlorocyclopent-4-en-1,3-dione with 1,3,5-trimethoxybenzene under Friedel-Crafts reaction conditions along with the expected 5-(2,4,6-trimethoxyphenyl)-4-chlorocyclopent-4-ene-1,3-dione obtained disubstituted product - 3,4-bis-(2,4,6-trimethoxyphenyl)-2-chlorocyclopent-2-en-1-one.
Metal-free reductive c-c-coupling between arylboronic acids and 2-(5-iodo-1,2,3-triazolyl)phenols
Authors: Gevondian A. G. , Kotovshchikov Y. N. , Latyshev G. V. , Lukashev N. V. , Beletskaya I. P.
Published: April 2024

A novel approach to 2-(1-arylalkyl)benzoxazoles via a reaction of arylboronic acids with 2-(5-iodo-1,2,3-triazolyl)phenols has been developed. The key intermediates of the proposed cascade transformation are 2-(1-diazoalkyl)benzoxazoles, entering reductive C-C-coupling with boronic acids. The reaction proceeds under transition-metal-free conditions and affords target compounds in yields up to 67%.
Three-component synthesis of new C3-substituted 5,6-dihydropyrrolo[2,1-a]isoquinolines
Authors: Miftyakhova A. R. , Sidakov M. B. , Borisova T. N. , Fakhrutdinov A. N. , Titov A. A. , Sorokina E. A. , Varlamov A. V.
Published: April 2024

New C3-substituted 5,6-dihydropyrrolo[2,1- a ]isoquinolines were obtained by a three-component domino reaction of 1-aroyl-3,4-dihydroisoquinolines, dimethylacetylenedicarboxylate, and CH-acids. The transformations proceed under microwave irradiation at 130°C in dry acetonitrile.
Oxidative heterocoupling of α-carbanions of lithium acylates with 1,2-dibromoethane
Authors: Zorin A. V. , Zaynashev A. T. , Zorin V. V.
Published: April 2024

The interaction of pairs of α-carbanions of lithium 2-methylpropanoate, butanoate, pentanoate, hexanoate, heptanoate and phenylacetate, generated from various CH-acids (A-H, B-H) under the action of lithium diisopropylamide in THF, with 1,2-dibromoethane leads to a mixture of products of oxidative homo[2,2,3,3-tetramethyl-, 2,3-diethyl-, 2,3-dipropyl-, 2,3-dibutyl-, 2,3-dipentyl- and 2,3 -diphenylsuccinic acids] and heterocoupling [2,2-dimethyl-3-ethyl-, 2-propyl-3-ethyl-, 2-butyl-3-ethyl-, 2-pentyl-3-ethyl-, 2-phenyl-3 -ethyl-, 2-butyl-3-propyl-, 2-pentyl-3-propyl-, 2-propyl-3-phenyl-, 2-butyl-3-pentyl-, 2-butyl-3-phenyl- and 2 -pentyl-3-phenylsuccinic acids] with a total yield of 83-99%. The selectivity of the formation of homo- and heterocoupling products depends on the structure of the coupled α-carbanions.
Synthesis and aggregation-induced emission of (z)-6-alkylamino-2-amino-4-(2-aryl-1-cyanovinyl)pyridine-3,5-dicarbonitriles
Authors: Bardasov I. N. , Alekseeva A. U.
Published: April 2024

( Z )-6-alkylamino-2-Amino-4-(2-aryl-1-cyanovinyl)pyridine-3,5-dicarbonitriles were obtained by reaction of ( Z )-2-amino-4-(2-aryl-1-cyanovinyl)-6-chloropyridine-3,5-dicarbonitriles with various amines, including biologically active ones. The study of the spectral-luminescent properties showed the solid state fluorescence with a maxima at 472-562 nm and its absence in solutions. An increase in the volume fraction of water in solutions above a certain level caused the appearance of fluorescence due to the formation of aggregates. The enhancement of fluorescence upon addition of the viscous solvent glycerol confirmed the presence of aggregation-induced emission of the synthesized compounds.
Synthesis, docking and biological activity of antimetabolites based on uraciles and 5-substituted 2,6-dimethylpyrimidin-4(3h)-ones
Authors: Harutyunyan A. A. , Sumbatyan A. S. , Hambardzumyan A. A. , Panosyan H. A. , Grigoryan A. S. , Stepanyan H. M. , Muradyan R. E.
Published: April 2024

5-Substituted 2,4-dimethyl-1,6-dihydropyrimidin-6-ones reacted with aromatic aldehydes to form 5-substituted (Z)-2-(2-aryl)-1-ethenylpyrimidin-6-ones, and in the reaction of 5-(4-fluorobenzyl)-2,6-dimethylpyrimidin-4(3 H )-one with 4-fluorobenzaldehyde, 5-(4-fluorobenzyl)-2,6-bis[( E )-4-fluorostyryl]pyrimidin-4(3 H )-one. Uracil and 5-fluorouracil were alkylated with 4-methoxy-2-chloromethylbenzaldehyde to give 2-[2,4-dioxoand 5-fluoro-2,4-dioxo-3,4-dihydropyrimidine-1(2 H )methyl]-4-methoxybenzaldehydes and are condensed with 5-substituted 2,4-dimethyl-1,6-dihydropyrimidin-6-ones to form 1-{5[( E )-2-(5-butyl-, arylmethyl-4-methyl6-oxo-1,6-dihydro-pyrimidin-2-yl)vinyl]-2-methoxybenzyl}uracil, 5-fluorouracil, and 5-bromouracil. The results of docking studies and data on the antibacterial, antitumor, and antimonoamine oxidase activity of the synthesized compounds are presented.
Circumambulatory migrations of arylazo groups in the systems of pentamethoxycarbonyland pentamethylcyclopentadiene
Authors: Dushenko G. A. , Mikhailov I. E. , Minkin V. I.
Published: April 2024

According to quantum chemical calculations CAM-B3LYP/6-311++G(d,p) intramolecular migrations of arylazo groups in 5-arylazo-1,2,3,4,5-pentamethoxycarbonylcyclopentadienes occur by a dissociative mechanism through the intermediate formation of tight ionic pairs with low energy barriers: Δ E ≠ZPE, benzonitrile, 14.0 (Ar = C6H4NO2-4) and 16.5 [Ar = C6H3(NO2)2-2,4] kcal/mol. In 5-arylazo-1,2,3,4,5-pentamethylcyclopentadienes, 1,5-sigmatropic shifts of arylazo groups occur along the perimeter of the five-membered ring in conformers with the exo position of the azo group relative to the cyclopentadiene ring with significantly higher activation barriers: Δ E ≠ZPE, benzonitrile, 30.3 (Ar = C6H4NO2-4) and 27.5 [Ar = C6H3(NO2)2-2,4] kcal/mol. The calculations are in good agreement with the data for these compounds obtained by us earlier by dynamic NMR.
Microwave activation in [FeCl3·6H2O–TfOH] - catalysed reaction of binor-s with organic nitriles
Authors: Frolova K. S. , Zosim T. P. , Akhmerova A. V. , Ramazanov I. R.
Published: April 2024

An efficient catalytic system, consisting of 20 mol % of FeCl3·6H2O and 20 mol % of trifluoromethanesulfonic acid, for amidation of binor-S in a solution of toluene using organic nitriles under microwave synthesis was developed. Typically the reaction proceeds at 100°C in 15 min.
Kinetics of the diels-alder reaction of 2,5-dimethylfuran with N-phenylmaleimide: high hydrostatic pressure, temperature, and solvent effects
Authors: Kornilov D. A.
Published: April 2024

The rate constants of the Diels-Alder reaction of 2,5-dimethylfuran (1) with N -phenylmaleimide (2) in 5 solvents in the range of temperature 25-45°C and pressure 1-1000 bar have been determined. Activation enthalpy, entropy, Gibbs free energy and volume parameters have been calculated. The equilibrium constants of the 1 + 2 reaction in benzene in the temperature range 25-55°C have been determined, and the reaction enthalpy and entropy have been calculated.
Iodination of propargylpyrazole in the presence of cadmium (II) acetate
Authors: Balyan K. V. , Pogosyan H. R. , Movsisyan L. A. , Sargsyan H. B. , Attaryan H. S. , Ayvazyan A. G. , Hobosyan N. G.
Published: April 2024

This paper describes an efficient synthetic method of iodine addition to the triple bond and substitution of the CH-acid hydrogen atom of propargylpyrazole in the presence of cadmium (II) acetate at room temperature, the role of solvents and the ratio of reagents during iodination are optimized.
sec-Alkylketoximes in the Trofimov reaction: from minor products to reagents of the XXI century
Authors: Shabalin D. A
Published: April 2024

This review summarizes the results and perspectives of studies of the reaction between sec -alkylketoximes having only one C-H bond at the α-position to the oxime function and acetylene in the presence of superbasic catalytic media. Selective syntheses of key intermediates of pyrroles assembly (3 H -pyrroles and 5-hydroxypyrrolines), their reactivity, and unique cascade assemblies of unpredictable products are discussed.
One-pot synthesis of (E)-3-(N-vinylpyrro-2-yl)acrylic acids
Authors: Shcherbakova V. S , Martynovskaya S. V , Gyrgenova E. A , Ushakov I. A , Ivanov A. V
Published: April 2024

The paper describes the synthesis of a previously unknown class of N -vinylpyrrolyl acrylic acids - multifunctional monomers and promising building blocks for fine organic synthesis, which was created on the basis of the fundamental works of academician Trofimov B.A., namely the synthesis of an inexhaustible class of N -vinylpyrroles.
N-arylation of 1,2,4- and 1,3,4-oxadiazolones under the conditions of activitated aromatic nucleophilic substitution
Authors: Konstantinova A. S , Shetnev A. A , Volobueva A. S , Korsakov M. K
Published: April 2024

The possibilities of N -arylation of 1,2,4-oxadiazol-5(4 Н )-ones and 1,3,4-oxadiazol-2(3 Н )-ones with various electron-deficient chloro- and fluorine-substituted nitroarenes under the conditions of classical activated nucleophilic substitution were studied. A significant difference was shown in the reactivity of 1,2,4- and 1,3,4-oxadiazolones in N -arylation reactions. Methods for the synthesis of N-nitroaryl derivatives have been developed.1,2,4- and 1,3,4-oxadiazolones, providing yields of target products with sufficient purity and good yields at the level of 65-96%.
Synthesis and antiarrhythmic activity of a new benzodioxolsubstituted 4-spirocycloalkan(tetrahydropyran)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolines
Authors: Arustamyan Zh. S. , Margaryan R. E. , Aghekyan A. A. , Panosyan G. A. , Mkrtchyan G. S. , Muradyan R. E.
Published: April 2024

By the reaction of 1-(3,4-dimethoxy)phenylcycloalkanmethan- and 4-(3,4-dimethoxyphenyl)tetrahydropyran-4-methanamines with benzo[ d ][1,3]dioxol-5-carbonyl chloride corresponding N -substituted benzo[ d ][1,3]dioxol-5-carboxamides were synthesized. Cyclization of the latter with phosphorus oxychloride gave dihydroisoquinolines reduced with sodium borohydride to the corresponding spiro-substituted tetrahydroisoquinolines, whose methylation according to Eschweiler-Clark reaction gave N -methyl derivatives. By condensation abovementioned amines with benzo[ d ][1,3]dioxol-5-carbaldehyde Schiff bases were synthesized. The reduction of the latter with sodium borohydride gave the corresponding secondary amines - non-cyclic analogues of tetrahydroisoquinolines, which undergo cyclization under the conditions of the Eschweiler-Clark reaction to form N -benzodioxolmethyl-substituted tetrahydroisoquinolines.
Synthesis and chemical transformations of 1-aryladamantanes
Authors: Ivleva E. A. , Orlinsky N. S. , Zaborskaya M. S. , Klimochkin Yu. N.
Published: April 2024

The synthesis was carried out and the transformations of 1-aryladamantanes in fuming nitric acid were studied. The reactions include nitroxylation of saturated cage and nitration of the aromatic moiety and lead to 3-(dinitroaryl)-1-adamantylnitrates. A number of new polyfunctional compounds have been synthesized based on reactions of substituted 3-(dinitroaryl)-1-adamantyl nitrates with nucleophiles in concentrated sulfuric acid. Due to the multifunctionality, the obtained compounds can be used as starting materials in the synthesis of substances with a wide spectrum of biological activity and materials with a complex of valuable properties.
Synthesis of new polycyclic adducts based on tetraazadecalin
Authors: Rakhimova E. B. , Kirsanov V. Yu.
Published: April 2024

A one-pot method has been developed for the synthesis of 4,9-dimethyl-2,3a,5a,7,8a,10a-hexaazaperhydropyrenes by catalytic heterocyclization of 2,6-dimethyl-1,4,5,8-tetraazadecalin with a cyclomethylating reagent (formaldehyde or tetramethylmethanediamine) and substituted anilines.
Synthesis of glycyl-(S)-5-hydroxynorvaline
Authors: Chulakov E. N. , Tumashov A. A. , Gruzdev D. A. , Levit G. L. , Krasnov V. P.
Published: April 2024

The dipeptide glycyl-( S )-5-hydroxynorvaline was obtained from 1- tert -butyl 5-methyl N -Boc-glycyl-( S )-glutamate as a result of saponification and subsequent reduction of the activated 5-carboxyl group with sodium borohydride followed by removal of the N -Boc and OBu t protecting groups by refluxing in a dioxane-water mixture. Using the example of the synthesis of ( S )-5-hydroxynorvaline, it has been shown that the used sequence of chemical transformations is not accompanied by racemization.
Synthesis and antituberculosis activity of new 5-alkynyl derivatives of 2-thiouridine: application of new scaffold
Authors: Platonova Ya. B. , Kirillova V. A. , Volov A. N. , Savilov S. V.
Published: April 2024

We herein describe new potent inhibitors of mycobacteria based on 5-substituted 2-thiouridine derivatives. A series of new 5-alkynyl-substituted 2-thiouridine derivatives were synthesized via palladium-catalysed Sonogashira cross-coupling reaction of 5-iodo-2-thiopyrimidine base with terminal acetylenes with good yields in DMF at room temperature. It was found that sulfur atom in C2 position of pyrimidine ring had no impact on yields of target compounds. All obtained compounds were evaluated for their antimycobacterial activity against Mycobacetrium bovis and Mycobacterium tuberculosis at concentrations of 0.1-100 µg/ml using MABA test. Synthesized nucleosides showed high antimycobacterial activity against Mycobacterium bovis and Mycobacteri um tuberculosis. The obtained MIC50 values of 2-thionucleosides 14, 15 and 16 (0.28-0.75 µg/ml) significantly exceed characteristics of reference drug rifampicin, D-cycloserine and isoniazid, which gives prerequisites for further more detailed studies.
Photoinitiated by red light (625 nm) iodosulfonylation of internal alkynes to synthesize β-iodovinylsulfones
Authors: Abramov V. A. , Topchiy M. A. , Malysheva A. S. , Beletskaya I. P. , Asachenko A. F.
Published: April 2024

Synthesis of β-iodovinyl sulfones was performed out by direct bifunctionalization of internal alkynes using an economical LED light source with a maximum emission wavelength of 625 nm. The products were obtained in high yields (68 to 99%) using equivalent amounts of reagents. The reaction of arylsulfonyl iodides with internal alkynes proceeds by a radical mechanism and is a regioselective method for the synthesis of β-iodovinyl sulfones.
Synthesis of heterocyclic analogues based on biscyanoethyl derivative of fusidic acid methyl ester
Authors: Salimova E. V. , Parfenova L. V.
Published: April 2024

As a result of chemical transformations of the 3,11-biscyanoethyl derivative of methylfusidate, new nitrogen-containing analogs of fusidic acid, bisamidoxime, bistetrazol, and 1,2,4-oxadiazoles, were synthesized.
Synchronous and zwitter-ion channels of (R)-5-methyl2-(1-methylethylidene)-cyclohexanone reaction with 4-phenyl-4H-1,2,4-triazoline-3,5-dione
Authors: Bodrikov I. V. , Kurskii Yu. A. , Chiyanov A. A. , Subbotin A. Yu. , Kuropatov V. A.
Published: April 2024

The interaction of pulegone with enophil - 4-phenyl-4 H -1,2,4-triazoline-3,5-dione leads to the formation of two described earlier epimers: 1-[(1 R ,4 R )-4-methyl-1-(1-methylethenyl)-2-oxocyclohexyl]-4-phenyl-1,2,4-triazolidine-3,5-dione ( RR -isomer) and 1-[(1 S ,4 R )-4-methyl-1-(1-methylethenyl)-2-oxocyclohexyl]-4-phenyl-1,2,4-triazolidine-3,5-dione ( SR -isomer). Along with these epimers, we found another isomer - 1-{1-methyl-1-[(4 R )-4methyl-6-oxocyclohex-1-en-1-yl]ethyl}-4-phenyl-1,2,4-triazolidine-3,5-dione. Quantum chemical modeling has established that isomeric products of hydrogen substitution in pulegone by enophil are formed along three routes. In the SR -isomer formation route, the ene reaction proceeds consistently. The other two routes are implemented with the enophil approach from the R -side of the pulegon. These routes consist of two consecutive stages. At the first stage, an intermediate of the type of asymmetric cyclic aziridine cation is formed. Elimination of a proton from one of the geminal methyl groups of the intermediate leads to an RR -isomer with a terminal double bond. When a proton is eliminated from the methylene group of the pulegog ring, an internal unsaturated compound is formed. The ratio of the yield of the isomer with an internal double binding and the RR -isomer depends on the polarity of the aprotic solvents.
ASSESSMENT OF BOTTOM SEDIMENT POLLUTION IN SMALL RIVERS, VLADIMIR REGION
Authors: Chesnokova S. M. , Savel’ev O. V.
Published: April 2024

The results of assessing pollution of bottom sediments in four small rivers of the Vladimir region with heavy metals (HM) and phosphates are presented. According to HM concentration coefficients characterizing the concentration (anomaly) of elements in bottom sediments in respect to their background content in the region, the zones of technogenic multi-element geochemical anomalies in the channels of all studied watercourses and their structure were identified. It has been established that Fe, Pb, Co, Cu, Zn, Cr, and Mn are the priority metals of technogenic geochemical anomalies in bottom sediments. The highest pollution of bottom sediments with these metals is typical for the zones influenced by the runoff from the territories of collective orchards, livestock complexes, large industrial cities and rural settlements. According to the total pollution indicator (Zc), which reflects the additive excess of the background content of a group of heavy metals that are part of technogenic geochemical anomalies, the studied watercourses are located in the following order: Sodyshka Kamenka Rpen Ilevna, and according to the phosphate content: Sodyshka Rpen  Kamenka Ilevna. Correlations between the components of bottom sediments have been studied. The average load of heavy metals and phosphates on watercourses was assessed.
HYDROCARBON CONTAMINATION IMPACT ON SANDY SOILS WITHIN THE DZUNBAYAN OIL FIELD (EASTERN MONGOLIA)
Authors: Garetova L. A. , Kharitonova G. V. , Imranova E. L.
Published: April 2024

The data are presented on the particle-size distribution, content of hydrocarbons, n-alkanes in their composition and the number of microorganisms in the soils of Dzunbayan oil production area (Mongolia, the Eastern Gobi desert steppe). The soils studied are characterized by the dominance of sand and fluid fraction (99.50–99.8%) with particles of 2–20 μm. The soils show alkaline reaction (pH 8.2–8.7), they are slightly saline in the control areas and highly saline (water extract salinity 0.13–2.34‰) near the production well. The content of petroleum hydrocarbons (HC) in soils of the study area varied from 9 to 60 mg/kg, with a maximum near the well. The study of the molecular composition of n-alkanes revealed the dominance of long-chain homologues (66.3–79.2% of the total n-alkanes), occurring at various stages of physicochemical and microbiological weathering. According to a number of features, the microbial community of soils is characterized by a high degree of adaptation to the conditions of the arid zone, salinity, and high pH values; at the same time, these conditions limit the development of typical representatives of soil microbiocenoses, i.e., actinomycetes and, to a greater extent, microscopic fungi. The total number of heterotrophic bacteria (HBGs) in the studied soil samples varied within 1.22–3.49 million CFU/g of soil. The proportion of oil-oxidizing bacteria (NOB) was 12.6–18.9% OBA, which corresponded to the high adaptive capacity of the community to hydrocarbons. Specific climatic conditions, features of soil composition, as well as oil with a predominance of heavy paraffin fractions of the Dzunbayan deposit, characterize the low potential ability of soils to self-purify under the oil pollution.
DEWATERING AS A LEADING FACTOR IN THE DEVELOPMENT OF SUFFUSION UPON THE CONSTRUCTION OF DEEP FOUNDATIONS
Authors: Kashperyuk P. I. , Moskalev D. S. , Khomenko V. P.
Published: April 2024

The article considers the main technogenic factors leading to the development of mechanical suffusion during the construction and operation of buildings and structures with deep foundations. At a specific object, the dynamics of the development of an ascending suffusion process of a “volcanic” nature (“pseudovolcanic suffusion”) caused by systematic water drawdown and discontinuity of the upper aquiclude during construction work was studied. It is proved that the need for constant pumping groundwater entering the drainage system results rather from the violation of the upper aquiclude continuity, serving the soil foundation upon the construction of “retaining wall” and pile foundation than from the engineering defects in the constructed impervious screen. The research results made it possible for the first time to evaluate the possibilities of using two methods for determining the development of the ascending suffusion process in time; the method of measuring the duty cycles with a caliper and the method of filling the duty cycles with medium-sized sand until the formed volume is completely filled. Based on the laws of hydrodynamics, an attempt was made to determine the speed of the upward flow and the magnitude of the hydrophysical head. It is noted that the most important condition for the production of engineering surveys, when identifying interstratal high-pressure aquifers in the soils of the base, should be the mandatory plugging of exploration wells with high-quality concrete mortar in the range of depths of the bottom of the upper aquiclude and, at least, the design mark of the bottom of the pit, immediately after the completion of drilling.
FEATURES OF THE STRUCTURE, FUNCTIONING AND RECONSTRUCTION OF THE LANDFILL NIZHNEKAMSKNEFTEKHIM PUBLIC JOINT STOCK Co.
Authors: Musin R. Kh. , Galieva A. R. , Kurlyanov N. A.
Published: April 2024

PJSC Nizhnekamskneftekhim is one of the largest petrochemical companies in Europe. Industrial production was launched there in 1967. Production waste is stored in a sludge reservoir and waste landfill. The landfill has been operating since 1982. It is equipped with systems of surface and underground drainage, impervious curtains, and two belts of observation wells. More than 0.5 million m3 of mostly solid waste III-V classes of hazard has been accumulated there. The landfill capacity is depleted by more than 80%. Its operation has led to a significant groundwater level rise (4.0–4.5 m) and groundwater pollution, the water salinity reaching 12.75 g/l, and hardness, 73.9 mmol/l. These negative hydrogeoecological effects are primarily due to increased atmospheric recharge of groundwater and the active interaction of atmospheric precipitation with the waste substance. There is plan to reconstruct the landfill. It involves encapsulating the waste in a watertight reservoir confined by artificial geosynthetic materials with extremely low filtration properties. Hydrodynamic and balance methods were used to determine the infiltration supply of groundwater in natural and disturbed conditions, productivity of underground drainage; the continuously formed flow rate of polluted groundwater, which is not intercepted by drainage system (with the flow discharge equal to 116.7 m3/day); as well as modern and predicted (postreconstruction) water balances. The effectiveness of the existing engineering protective structures of the landfill was assessed. It is shown that the planned reconstruction should lead to a decrease in the groundwater level and its pollution degree. In this case, the concentrations of organic substances, which are the priority pollutants, will decrease most intensely. The geological environment of the landfill site is characterized by significant buffer (protective) properties. They control just local spreading of contaminated groundwater. According to the data of numerous different-time sampling at a distance of 1.0–1.5 km from the landfill in the direction of groundwater current spreading, no signs of pollution caused by the landfill operation are registered. The main processes determining the self-purification of groundwater are as follows: dilution of polluted water by pure infiltration nutrition, the minimum layer of which is 67.6 mm/year; chemo- and biodestruction of pollutants, their sorption, diffusion-dispersion scattering and precipitation as pH–Eh conditions change.