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Archive for A. Grevtsev

17 Apr 2018
Acknowledging publications • Publications

ACS Biomater. Sci. Eng, 2018, 491-501

M. Promzeleva, T.V. Volkova, A.N. Proshin, O.I. Siluykov, A. Mazur, P.M. Tolstoy, S.P. Ivanov, F. Kamilov, I.V. Terekhova

“Improved biopharmaceutical properties of oral formulations of 1,2,4-thiadiazole derivative with cyclodextrins: in vitro and in vivo evaluation”

ACS Biomater. Sci. Eng, 2018, 4(2), 491-501
DOI: 10.1021/acsbiomaterials.7b00887

source: https://pubs.acs.org/doi/10.1021/acsbiomaterials.7b00887

The synthesized 1,2,4-thiadiazole derivative displaying biological activity has low aqueous solubility and dissolution rate. Novel oral formulations of thiadiazole with β- and hydroxypropyl-β-cyclodextrins were obtained by grinding and freeze-drying methods with the purpose to improve the aqueous solubility. Complex formation of 1,2,4-thiadiazole derivative with cyclodextrins was confirmed by means of solid-state 13C MAS CP/TOSS NMR. Solubility, dissolution rate and permeability of the solid inclusion complexes were evaluated in different biorelevant media (SGF, FaSSGF, FaSSIF) simulating the conditions in the gastrointestinal tract. It was demonstrated that the content of biorelevant media affects the properties of the inclusion complexes. In particular, solubilizing effect of cyclodextrins became less pronounced when the micelles of taurocholic acid and lecithin are formed in the dissolution media. The inclusion of thiadiazole into cyclodextrin cavity is in competition with its partitioning into the micelles and this should be taken into account when the in vivo behavior is predicted. The results of in vitro and in vivo experiments were found to be in agreement and showed the highest solubility, dissolution rate and bioavailability of the freeze-dried complexes of thiadiazole with hydroxypropyl-β-cyclodextrin. These complexes can be proposed as more effective dosage forms for oral administration.

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14 Apr 2018
Publications

J. Phys. Chem. C, 2018, 1711-1720

E.Yu. Tupikina, M. Bodensteiner, P.M. Tolstoy, G.S. Denisov, I.G. Shenderovich

“P=O Moiety as an Ambidextrous Hydrogen Bond Acceptor”

J. Phys. Chem. C, 2018, 122(3), 1711-1720
DOI: 10.1021/acs.jpcc.7b11299

source:https://pubs.acs.org/doi/10.1021/acs.jpcc.7b11299

Hydrogen bond patterns of crystals of phosphinic, phosphonic, and phosphoric acids and their cocrystals with phosphine oxides were studied using 31P NMR and single-crystal X-ray diffraction. Two main factors govern these patterns and favor or prevent the formation of cocrystals. The first one is a high proton-accepting ability of the P═O moiety in these acids. As a result, this moiety effectively competes with other proton acceptors for hydrogen bonding. For example, this moiety is a stronger proton acceptor than the C═O moiety of carboxylic acids. The second factor is the inclination of the P═O moiety of both the acids and the oxides to form two hydrogen bonds at once. The peculiarity of these bonds is that they weaken each other to a little degree only. In order to highlight this point, we are using the term “ambidextrous”. These two features should govern the interactions of P═O moiety with water and other proton donors and acceptors in molecular clusters, the active sites of enzymes, soft matter, and at surfaces.

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09 Apr 2018
Acknowledging publications • Publications

Phys. Chem. Chem. Phys., 2018, 4901-4910

V.V. Mulloyarova, I.S. Giba, M.A. Kostin, G.S. Denisov, I.G. Shenderovich, P.M. Tolstoy

“Cyclic Trimers of Phosphinic Acids in Polar Aprotic Solvent: Symmetry, Chirality and H/D Isotope Effects on NMR Chemical Shifts”

Phys. Chem. Chem. Phys., 2018, 20, 4901-4910
DOI: 10.1039/C7CP08130H

The hydrogen-bonded self-associates of dimethylphosphinic (1), diphenylphosphoric (2), phenylphosphinic (3), and bis(2,4,4-trimethylpentyl)phosphinic (4) acids have been studied by using liquid-state NMR down to 100 K in a low-freezing polar solvent, CDF3/CDClF2. The H/D isotope effects on 1H NMR chemical shifts caused by partial deuteration of hydroxyl groups unambiguously reveal the stoichiometry of the self-associates and the cooperativity of their hydrogen bonds. In all cases, cyclic trimers are the dominant form, while cyclic dimers are present as a minor form for 1 and 2. Due to the asymmetry of substituents, cyclic trimers of 3 exist in two isomeric forms, depending on the orientation of the phenyl groups with respect to the plane of the hydrogen bonds. The racemic mixture of 4 leads to the coexistence of up to 64 isomers of cyclic trimers, many of which are chemically equivalent or effectively isochronous. The mole fractions of such isomers deviate from the statistically expected values. This feature could provide information about the relative stabilization energies of hydrogen-bonded chiral self-associates. The complexation of 4 with SbCl5 (complex 5) suppresses the self-association and 5 exists exclusively in the monomeric form with chemically non-equivalent 31P nuclei in RS, SR and RR/SS forms

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06 Apr 2018
Process

March

Total in March 2749 service applications were carried out.
All together measured:

  • 2596 1H spectra
  • 462 13C spectra
  • 157 DEPT spectra
  • 67 COSY spectra
  • 53 NOESY spectra
  • 111 31P spectra
  • 144 19F spectra

299 applications were carried out.

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22 Mar 2018
Acknowledging publications • Publications

J. Polym. Sci. A, 2018, 387-398

V.A. Rozentsvet, O.A. Stotskaya, V.P. Ivanova, M.G. Kuznetsova, P.M. Tolstoy, S.V. Kostjuk

“Structural characterization of polybutadiene synthesized via cationic mechanism”

J. Polym. Sci. A, 2018, 56, 387-398
DOI: 10.1002/pola.28905

 

The microstructure of polybutadiene synthesized via cationic polymerization using TiCl4‐based initiating systems has been investigated using 1D (1Н, 2Н, and 13С) and 2D (HSQC and HMBC) NMR spectroscopy. It was found that trans‐1,4‐unit is predominant structure of unsaturated part of polymer chain. Besides, the small amount of 1,2‐structures was also detected, while cis‐1,4‐units were totally absent. The signals of carbon atoms of three types of head groups (trans‐1,4‐, 1,2‐, and tert‐butyl) and two types of end groups (trans‐1,4‐Cl and 1,2‐Cl) were identified for the first time in macromolecules of cationic polybutadiene. It was showed that tert‐butyl head groups were formed due to the presence in monomer of admixtures of isobutylene. The new methodology for calculation of the content of different structural units in polybutadiene chain as well as the head and end groups was proposed. It was established that main part of 1,2‐units distributed randomly along the polybutadiene chain as separate units between trans‐1,4‐structures.

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22 Mar 2018
Seminars

FIRST

source:http://www.cimo.fi/programmes/first

21.03.2018 P.M. Tolstoy has given a lecture on “NMR of Hydrogen Bonded Systems” for the Bachelor and Master students from the University of jyväskylä (Finland) during the Russian-Finnish student seminar within the framework of FIRST exchange program. Events program in Institute of Chemistry.

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16 Mar 2018
Acknowledging publications

New Journal of Chemistry, 2017, 41, 13918-13928

A.A. Vereschagin, V.V. Sizov, P.S. Vlasov, E.V. Alekseeva, A.S. Konev, O.V. Levin

“Water-stable [Ni(salen)]-type electrode material based on phenylazosubstituted salicylic aldehyde imine ligand”

New Journal of Chemistry, 2017, 41, 13918-13928
DOI: 10.1039/c7nj03526h

source: http://pubs.rsc.org/en/Content/ArticleLanding/2017/NJ/C7NJ03526H#!divAbstract 

A novel electrode material was prepared by electrochemical oxidation of [4,4′-phenylazo-2,2′-(ethylenediimino-κ2N-methyl)diphenolate-κ2O]nickel, a [Ni(II)(salen)]-type complex, in chlorinated solvent. The chemical structure of the material was explored by FTIR, NMR and XPS techniques to determine the main components of the material and the nature of the linkage between them. The morphology of the material films was explored by SEM analysis. The electrochemical properties of the new material were studied by a set of voltammetric methods and an unusual stability of the material in aqueous medium was observed.

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12 Mar 2018
Acknowledging publications

Tetrahedron, 2017, 73, 671-680

M.M. Efremova, R.R. Kostikov, A.V. Stepakov, T.L. Panikorovsky, V.S. Shcherbakova, A.V. Ivanov, A.P. Molchanov

“Unusual Lewis-acid catalyzed formal (3+3)-cycloaddition of azomethine imines and nitrones to N-vinylpyrroles”

Tetrahedron, 2017, 73, 671-680
DOI: 10.1016/j.tet.2016.12.034

source:https://www.sciencedirect.com/science/article/pii/S0040402016313217?via%3Dihub 

The addition of Lewis acids change the reaction mechanism of the cycloaddition of N-vinylpyrroles with azomethine imine and C,N-diarylnitrones. The formal (3+3)-cycloaddition is observed instead of (3+2)-dipolar cycloaddition, which take place in the absence of catalysts. This unusual (3+3)-cycloaddition leads to heterocyclic compounds with pyrazolo[1,2-a]pyrrolo[1,2-d][1,2,4]triazine- and pyrrolo[2,1-d][1,2,5]oxadiazine cores, which are difficultly achievable by other methods.

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06 Mar 2018
Acknowledging publications

Mendeleev Commun., 2017, 27, 95-96

G. P. Kantin, M. Yu. Krasavin

“Microwave-promoted reaction of N-alk-1-enyl chloroacetamides with sodium azide unexpectedly yields 1H-imidazol-5(4H)-ones”

Mendeleev Commun., 2017, 27, 95-96
DOI: 10.1016/j.mencom.2017.01.031

source: https://www.sciencedirect.com/science/article/pii/S0959943617300317?via%3Dihub

A novel method to prepare biologically relevant 1H-imidazol-5(4H)-ones from aliphatic amines, isobutyraldehyde, chloroacetyl chloride and sodium azide under microwave irradiation has been developed.

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05 Mar 2018
Process

February

Total in February 2014 service applications were carried out.
All together measured:

  • 1848 1H spectra
  • 366 13C spectra
  • 87 DEPT spectra
  • 41 COSY spectra
  • 22 NOESY spectra
  • 85 31P spectra
  • 91 19F spectra

239 applications were carried out.

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