N 10 N-(2-Carboxyethyl)chitosans: Regioselective synthesis, characterisation and protolytic equilibria [Text] / Yu. A. Skorik, C. A. R. Gomes, M. T.S.D. Vasconcelos, Yu. G. Yatluk // Carbohydrate Research. - 2003. - Vol. 338, № 3. - P271-276 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): CARBOXYETHYLATION POLYSACCHARIDES -- N-(2-CARBOXYETHYL)CHITOSAN -- POLYAMPHOLYTE Аннотация: N-(2-Carboxyethyl)chitosans were obtained by reaction of low molecular weight chitosan with a low degree of acetylation and 3-halopropionic acids under mild alkaline media (pH 8-9, NaHCO3) at 60°C. The chemical structure of the derivatives obtained was determined by 1H and 13C NMR spectroscopies. It was found that alkylation of chitosan by 3-halopropionic acids proceeds exclusively at the amino groups. The products obtained are described in terms of their degrees of carboxyethylation and ratio of mono-, di-substitution and free amine content. The protonation constants of amino and carboxylate groups of a series of N-(2-carboxyethyl)chitosans were determined by pH-titration at ionic strength 0.1 M KNO3 and 25°C. © 2002 Elsevier Science Ltd. All rights reserved. |
C 74 Complexation models of N-(2-carboxyethyl)chitosans with copper(II) ions [Text] / Yu. A. Skorik, C. A. R. Gomes, N. V. Podberezskaya, G. V. Romanenko, L. F. Pinto, Yu. G. Yatluk // Biomacromolecules. - 2005. - Vol. 6, № 1. - P189-195 . - ISSN 1525-7797 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: The copper(II) complex formation equilibria of N-(2-carboxyethyl)chitosans with three different degrees of substitution (DS = 0.42, 0.92, and 1.61) were studied in aqueous solution by pH-potentiometric and UV-spectrophotometric techniques. It was demonstrated that the complexation model of CE-chitosans depends on DS: the [Cu(Glc-NR2)2] complexes are predominant for two lower substituted samples ("bridge model", log ?12 = 10.06 and 11.6, respectively), whereas the increase of DS leads to formation mainly of the [Cu(Glc-NR2)] complexes ("pendant model", log ?11 = 6.41). As a model for copper complexation with a disubstituted residue of CE-chitosan, the complex of N-methyliminodipropionate [CuMidp(H2O)]·(H2O) was synthesized and structurally characterized by XRD. The unit cell consists of two crystallographically nonequivalent Cu atoms having slightly distorted square pyramidal coordination; Midp constitutes the basal plane of the pyramid and acts as a tetradentate NO3 chelate-bridging ligand by the formation of two six-membered chelate rings (average Cu-O 1.99 A, Cu-N 2.04 A) and a bridge via carbonyl O atom (average Cu-O 1.99 A), an apical position is occupied by a water molecule (average Cu-Ow 2.30 A). |
N 10 N-alkylation of chitosan by beta-halopropionic acids in the presence of various acceptors [Text] / A. V. Pestov, Yu. A. Skorik, G. Kogan, Yu. G. Yatluk // Journal of Applied Polymer Science . - 2008. - Vol. 108, № 1. - P119-127 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: N-carboxyethylation of chitosan by -halopropionic acids in the presence of various proton and halogen ion acceptors was investigated. It has been observed that carboxyethylation of chitosan in aqueous medium is accompanied by the by-processes of hydrolysis and dehydrohalogenation of the -halopropionic acids yielding -hydroxypropionic acid, bis(2-carbox-yethyl) ether, and acrylic acid. Degree of carboxyethyl substitution (DS) of chitosan and the relative rates of the by-processes varied significantly depending on the conditions used and nature of the proton or halogen ion acceptor. At carboxyethylation of chitosan with the alkaline -bromopropionates, the DS increased in the order Cs+ Rb- K+ sim; Na+ Li-. |
A 62 Antioxidant and antimutagenic activity of N-(2-carboxyethyl)chitosan [Text] / G. Kogan, Yu. A. Skorik, I. Zitnanova, L. Krizkova, Z. Durackova, C. A. R. Gomes, Yu. G. Yatluk, J. Krajcovic // Toxicology and Applied Pharmacology . - 2004. - Vol. 201, № 3. - P303-310 : ил. - Библиогр.: с. 309-310 (49 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): CARBOXYETHYLATION -- CHITOSAN -- EUGLENA GRACILIS -- OFLOXACIN -- ANTIOXIDANT -- ANTIMUTAGENICITY Аннотация: The antioxidant and antimutagenic activities of the novel carboxyethyl derivatives of chitosan with three different degrees of substitution have been assayed in vitro in the unicellular flagellate Euglena gracilis subjected to the action of genotoxic agents acridine orange and ofloxacin. It has been demonstrated that chitosan derivatives exhibit concentration-dependent protective antigenotoxic activity against both mutagens. It is suggested that different mechanisms may be involved in its protective action—antioxidant activity in case of ofloxacin-induced DNA damage, as well as possible interaction with the cell membrane that prevents acridine orange from reaching the genetic compartments and subsequent damaging DNA through intercalative binding. Direct adsorption of acridine orange on chitosan derivatives was ruled out as a possible mechanism of protection on the basis of spectrophotometric measurements. Dependence of the antimutagenic properties of the studied chitosan derivatives on the degree of substitution was reversed in experiments involving acridine orange and ofloxacin, which also indicated different mechanisms of protection involved in these two cases.???? |
H 43 Heavy metals removal by flocculation/precipitation using N-(2-carboxyethyl)chitosans [Text] / S. YU. Bratskaya, A. V. Pestov, Yu. G. Yatluk, V. A. Avramenko // Colloids and Surfaces A: Physicochemical and Engineering Aspects. - 2009. - Vol. 339, № 1-3. - P140-144 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: Here we report on solution properties and flocculation performance of polyampholyte chitosan derivatives - N-carboxyethylated chitosans (CEC) - synthesized "in gel" by treatment of chitosan with acrylic acid. We show that carboxyethylation with the substitution degrees (DS) from 0.7 to 1.6 yields water-soluble derivatives, whose isoelectric points (IEP) range from 6.30 to 3.55. At pH 7.5 interaction of negatively charged CEC derivatives with positively charged colloids of the heavy metal hydroxides (Zn2+, Cu2+, Ni2+), serving as a model of postgalvanic wastewaters, results in lowering of electrokinetic potential of the hydroxide colloids and their precipitation at appropriate flocculant dose. Investigations of CEC flocculation performance depending on pH and DS show that the efficiency of metal removal decreases in the row Cu2+ Zn2+ Ni2+ corresponding to the row of the hydroxocomplex stability for these metals. The higher was pH of the system and DS of CEC derivative, the narrower was the flocculation window and the stronger was negative effect of flocculant overdosing on the efficiency of heavy metal removal. Based on the estimation of floc settling rates and the residual metal concentrations, we have concluded that the optimal DS of CEC derivatives for the precipitation of metal hydroxides is 0.7-1.0 |
A 10 A generalized model of protolytic, complexing and colloidal properties of polyelectrolytes. Case study : N-(2-carboxyethyl)chitosans [] : доклад, тезисы доклада / S. YU. Bratskaya, A. Golikov, A. V. Pestov, A. Voit, Yu. G. Yatluk, V. A. Avramenko // EUCHIS 2009 - 9th International Conference of the European Chitin Society , Venice, Italy, 23-26 May 2009 : conference book. - Venice, Italy, 2009. - 21 (P1-5) Рубрики: ХИМИЧЕСКИЕ НАУКИ |
Y 32 Yatluk, Yu. G. Novel unique reagent for preparation of carboxyethyl chitosan-beta-acryloyloxyproprionic acids [] : доклад, тезисы доклада / Yu. G. Yatluk, A. V. Pestov, Yu. A. Skorik // 10-th International Conference on Chitin and Chitosan - 7th International Conference of the European Chitin Society, Le Corum, Montpellier, France, 6-9 September 2006 : book of abstracts . - Le Corum, Montpellier (France), 2006. - 77 (PC 13) Рубрики: ХИМИЧЕСКИЕ НАУКИ |
P 49 Pestov, A. V. In-gel synthesis of N-(2-carboxyethyl)chitosan [] : доклад, тезисы доклада / A. V. Pestov, Yu. G. Yatluk, Yu. A. Skorik // Proceedings of the 7th Asia-Pacific Chitin and Chitosan Symposium "Advances in chitin science and technology", Bexco, Busan, Korea, 23-26 April 2006. - Handrimwon, 2006. - С. 90-91. - Библиогр.: с. 91 (9 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ |
P 49 Pestov, A. V. Synthesis in a gel as a new procedure for preparing carboxyethyl chitosan [Electronic resource] / A. V. Pestov, N. A. Zhuravlev, Yu. G. Yatluk // Russian Journal of Applied Chemistry. - 2007. - Vol. 80, № 7. - P1154-1159. - Bibliogr. : p. 1159 (14 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: A fundamentally new procedure of synthesis of carboxyethyl chitosan in a physical gel, ensuring higher degree of substitution at lower temperatures and lower consumption of time and chemicals, compared to the existing procedures, was developed. The structure of the resulting products was examined by diffuse reflection IR and 1H NMR spectroscopy in solutions and also 1H and 7Li broad line NMR \\\\Expert2\\nbo\\Russian Journal of Applied Chemistry\\2007, v. 80, N. 7, p.1154.pdf |
T 44 The first cubane-like complex of copper based on N -carboxyethyl-tris(hydroxymethyl)aminomethane: Synthesis and crystal structure [Electronic resource] / A. V. Pestov, A. V. Virovets, N. V. Podberezskaya, Yu. G. Yatluk // Russian Journal of Coordination Chemistry. - 2008. - Vol. 34, № 1. - P1-7. - Bibliogr. : p. 7 (9 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: The interaction of acrylic acid with tris(hydroxymethyl)aminomethane (I) was studied. A simple method was suggested for preparing N-carboxyethyl-tris(hydroxymethyl)aminomethane (homotricin) (II). On the basis of compound II, the 1:1 Cu complex, [Cu(OCH2C(CH2OH)2NHCH2CH2COO)]4·nH2O (n = 4–11.25) (III), which is alkoxycarboxylate, was synthesized. The crystal structure of III was found to correspond to a cubane-like tetranuclear cluster (an automated Bruker X8Apex diffractometer with CCD detector (MoK radiation, graphite monochromator, v = 1.11°-27.5°), 8016 reflections, space group P , a = 12.5573(3), b = 19.1012(4), c = 21.2903(5) A, a = 80.7770(10)°, beta = 75.7430(10)°, y = 75.2260(10)°, V = 4761.62(19) A3, p(calcd.) = 1.704 g/cm3, Z = 4). The crystals are unstable due to the large number of water molecules \\\\Expert2\\nbo\\Russian Journal of Coordination Chemistry\\2008, v. 34, N. 1, p.1.pdf |
P 93 Protolytic Equilibria of Some N,N-Bis(2-carboxyethyl)aminoazobenzenesulfonic Acids in Aqueous Solution [Electronic resource] / Yu. A. Skorik, L. K. Neudachina, A. V. Osintsev, Yu. G. Yatluk, A. A. Vshivkov, E. V. Osintseva // Russian Journal of Organic Chemistry (Translation of Zhurnal Organicheskoi Khimii). - 2002. - Vol. 38, № 3. - P385-389 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: 4-[4-Bis(2-carboxyethyl)aminophenylazo]benzenesulfonic acid and 4-[2-bis(2-carboxyethyl)amino-4,5-dimethylphenylazo]benzenesulfonic acid were synthesized for the first time by azo coupling of diazosulfanilic acid with N,N-bis(2-carboxyethyl)aniline and N,N-bis(2-carboxyethyl)-3,4-xylidine, respectively. The acid ionization constants of the products were determined, their electron absorption spectra were measured, and schemes of acid-base equilibria in aqueous solution were proposed \\\\Expert2\\nbo\\Russian Journal of Organic Chemistry\\2002, 38 (3), 385.pdf |
3,3,3-Trifluoro-N-(3-trifluoromethylphenyl)-1,2-propanediamine and its N-mono-and N,N-dicarboxyethyl derivatives: synthesis, protolytic and complexation properties [Electronic resource] / V. Yu. Korotaev, Yu. A. Skorik, A. Yu. Barkov, M. I. Kodess, A. Ya. Zapevalov // Russian Chemical Bulletin (Translation of Izvestiya Akademii Nauk, Seriya Khimicheskaya). - 2005. - Vol. 54, № 11. - P2545-2549 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: 3,3,3-Trifluoro-N-(3-trifluoromethylphenyl)-1,2-propanediamine (5) was synthesized by the reaction of 2-diazo-1,1,1-trifluoro-3-nitropropane or 3,3,3-trifluoro-1-nitropropene with 3-aminobenzotrifluoride followed by the reduction of the nitro group. The Michael 1,4-addition of diamine 5 to acrylic acid occurs only at the N(1) atom and affords N-mono-or N,N-dicarboxyethyl derivatives 6 and 7, depending on the reactant ratio. Protolytic equilibria 5–7 in aqueous solutions were studied by pH-potentiometry and UV spectroscopy. Only the aliphatic amino group can be protonated in an aqueous solution, while the aromatic amino group remains unprotonated even in 12 M HCl. The stability constants of transition metal (Cu2+, Ni2+, Zn2+) complexes with ligands 5–7 were determined by pH-potentiometric titration. The stability of the complexes and selectivity of the ligands toward Cu2+ ions increase with an increase in the number of N-carboxyethyl groups \\\\Expert2\\nbo\\Russian Chemical Bulletin\\2005, 54 (11), 2545.pdf |
O-84 Osintseva, E. V. Protolytic properties and complexation with copper(II) ions of some azo derivatives of beta-arylaminopropionic acids [Electronic resource] / E. V. Osintseva, L. K. Neudachina, Yu. G. Yatluk // Russian Journal of Inorganic Chemistry (Zhurnal Neorganicheskoi Khimii). - 2010. - Vol. 55, № 10. - P1644-1650 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: The azo coupling reaction of N-(2-carboxyethyl)anthranilic acid and N,N,N,N-tetrabis(2-carboxyethyl)-1,3-phenylenediamine with diazosulfanilic acid yielded the complexones sodium 4-N-(2-carboxyethyl)amino-5-carboxyazobenzene-4?-sulfonate (I) and 2,4-N,N,N,N-tetrabis(2-carboxyethyl)diaminoazobenzene-4?-sulfonic acid (II), respectively. The acidity constants of I and II (20°C = 0.1M KCl) were determined to be as follows: for I, pK 00 = 1.29 ± 0.13, pK 0 = 2.92 ± 0.07, pK 1 = 3.92 ± 0.05, pK 2 = 5.16 ± 0.03; for II, pK 00 = 2.35 ± 0.06, pK 0 = 2.81 ± 0.09, pK 1 = 3.21 ± 0.11, pK 2 = 3.81 ± 0.09, pK 3 = 4.34 ± 0.04, pK 4 = 5.03 ± 0.06, pK 5 = 6.67 ± 0.07. The electronic absorption spectra of I and II were measured, and acid-base equilibrium scheme for I and II in aqueous solutions were suggested. The complexation constants of I and II with copper(II) ions were determined to be logK CuQI= 5.47 ± 0.06 and logK CuQII= 5.72 ± 0.13 (20°C = 0.1 M KCl). ?? \\\\Expert2\\nbo\\Russian Journal of Inorganic Chemistry\\2010, v. 55, N 10, с.1644.pdf |
S 66 Skorik, Yu. A. Evaluation of various chitin-glucan derivatives from Aspergillus niger as transition metal adsorbents [Text] / Yu. A. Skorik, A. V. Pestov, Yu. G. Yatluk // Bioresource Technology . - 2010. - Vol. 101, № 6. - P1769-1775 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: A number of chelating resins were prepared by chemical derivatization of the chitin-glucan (CG) complex isolated from Aspergillus niger biomass, namely chitosan-glucan (CsG), O-carboxymethyl-chitin-glucan (CM-CG), O-(2-sulfoethyl)chitin-glucan (SE-CG), and N-(2-carboxyethyl)chitosan-glucan (CE-CsG). The chemical modification was confirmed by FT-IR and elemental analysis. Nanosecond electron beam irradiation was used to produce insoluble resins and to preserve the reactive functional groups. Batch experiments were carried out to evaluate the adsorption selectivity and capacity of the resins toward transition metal ions (Cu2+, Ni2+, Co2+, Zn2+). The resins showed good adsorption capability with the following selectivity series: Co2+ Ni2+ Cu2+ Zn2+. The total metal adsorption capacities of CG, CsG, CM-CG, SE-CG, and CE-CsG resins at pH 6.5 (ammonium acetate buffer) were found to be 0.205, 0.382, 1.752, 0.319, and 0.350 mmol g?1, respectively. Our results suggest that, depending on the type of chemical modification, the chitin-glucan complexes can be used either for selective Cu2+ removal (CsG) or for total transition metal adsorption (CM-CG) from aqueous effluents |
C 74 Complexes of mono- and bis(2-carboxyethyl)-2-picolylamine: Synthesis and crystal and molecular structures [Electronic resource] / A. V. Pestov, A. E. Permyakov, P. A. Slepukhin, L. K. Neudachina, Yu. G. Yatluk // Russian Journal of Coordination Chemistry. - 2010. - Vol. 36, № 10. - P769-777 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: N-(2-Pyridylmethyl)iminodipropionic (I) and N-(2-pyridylmethyl)-3-aminopropionic acids (II) were obtained. A reaction of acid I with a Cu(II) salt gave a 2: 2 complex (III); a reaction of acid II with a Ni(II) salt yielded a 1 : 2 complex (IV). The crystal structures of these complexes were determined by X-ray diffraction. The abilities of compounds I and II to form complexes were compared with the literature data for other ligands containing the N-(2-pyridylmethyl)amino fragment. The structural features of the chelate complexes with 2-aminomethylpyridine derivatives were revealed, depending on the other substituents and the metal center \\\\Expert2\\nbo\\Russian Journal of Coordination Chemistry\\2010, v. 36, N. 10, p.769.pdf |
S 45 Selective mоnо-N-2-carboxyethylation of chitosan in the presence of magnesium halides [Text] / A. V. Pestov, M. I. Kodess, E. G. Matochkina, Yu. G. Yatluk // Carbohydrate Polymers. - 2011. - Vol. 86, № 2. - P783-788. - Bibliogr. : p. 787-788 (19 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: The solubility of chitosan in aqueous solutions of lithium and magnesium halides varies in the order: LiCl LiBr LiI; MgCl2 MgBr2 MgI2. A method for selective production of mono-N-(2-carboxyethyl)chitosan (NCE-chitosan) was developed by synthesis in gel (concentration of chitosan 4-20%) of the magnesium halides solution (1.1-3.5 M) using acrylic acid. Using for reaction of MgI2 or MgBr2 provides relative greater amount of the monosubstituted amino groups (73-87%) in comparison with their absence (50-70%) at the high degree of substitution (DS) more than 0.7. DS of the prepared NCE-chitosan and the ratios mono-: disubstitution of amino groups was determined by 1H NMR spectroscopy. The chemical structure of the obtained NCE-chitosan was characterized by FT-IR and 13C NMR spectroscopies \\\\Expert2\\nbo\\Carbohydrate Polymers\\2011, v. 86, p.783.pdf |
S 98 Synthesis, characterization and some properties of N-(2-carboxyethyl)chitosan [Text] / Yu. A. Skorik, C. A. R. Gomes, M. T.S.D. Vasconcelos, Yu. G. Yatluk // Advances in Chitin Science : Proceedings of the 5th Asia Pacific Chitin and Chitosan Symposium & Exhibition, Bangkok, Thailand, March 13-15, 2002. - Bangkoki, 2002. - Vol. 5. - P344+348 : il. - Bibliogr. : p. 348 (19 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): CHITOSAN -- CARBOXYETHYL -- ALKYLATION -- POLYAMPHOLYTE -- POTENTIOMETRIC TITRATION -- PROTONATION CONSTANTS |
N 58 Nickel(II) and copper(II) complexes based on N-(2-Carboxyethyl) alkanolamines: Influence of the amino alcohol structure on the coordination sphere of the metal center [Electronic resource] / A. V. Pestov, P. A. Slepukhin, O. V. Koryakova, V. N. Charushin // Russian Journal of Coordination Chemistry. - 2014. - Vol.40, №4. - С. 216-223. - Bibliogr. : p. 223 (28 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): NICKEL(II) COMPLEXES -- ALCOHOL STRUCTURE -- ALKANOLAMINES Аннотация: New nickel(II) complexes based on N-(3-hydroxypropyl)-β-alanine, N-(bis(hydroxyme -thyl)methyl)-β-alanine, and N-(tris(hydroxymethyl)methyl) -β-alanine are synthesized, and their structures are studied by X-ray diffraction analysis. The coordination spheres of the nickel and copper metal centers in the condensed phase are compared for a series of N-substituted β-alaninate ligands with the regularly changed dentate mode. In the case of the copper(II) complexes, an increase in the size of the alkanolamine chelate ring or the number of hydroxymethyl groups provides the formation of achiral coordination struc -tures, whereas the structures of the nickel(II) complexes are independent of the size of the lkanolamine che -late ring or the number of hydroxymethyl groups, thus providing the formation of the complexes as racemic modifications \\\\expert2\\nbo\\Russian Journal of Coordination Chemistry\\2014, v. 40, N. 4, p.216.pdf |
Activation effect of β-alanine and chitosan derivative on A. glycyphyllos and A. membranaceus seed germination and seedling growth and development / L. A. Khamidullina, A. V. Pestov, P. D. Tobysheva [et al.] // Agronomy research. - 2021. - Vol. 19, № 2. - P484-495 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: Agricultural cultivation of astragalus is fraught with a number of difficulties caused by both certain requirements for climatic conditions and individual characteristics of plants of this genus. In this study, carboxyalkylated derivative of chitosan was first proposed to use for improvement of astragalus propagation. Effects of N-(2-carboxyethyl)chitosan on in vitro A. glycyphyllos and A. membranaceus seed germination and seedling growth and development in comparing with β-alanine and chitosan acetate were detected. Carboxyethylation of chitosan leads to an increase in hydrophilic properties of the molecule, which enhances a penetration of nutrients inside the plant owing to improved solvating effect and bioadhesive activity. Seed germination assay were performed on Murashige-Skoog growth medium with or without tested compounds. N-2-Carboxyethylated derivative of chitosan was found to demonstrate active stimulating effect on the plant growth and development, contrary to the effect of acetate chitosan, but not to cause an activating effect on seed germination, while β-alanine does. |