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RSC Adv., 2017, 7, 10070-10073

A.S. Smirnov, D.N. Nikolaev, V.V. Gurzhiy, S.N. Smirnov, V.S. Suslonov, A.V. Garabadzhiu, P.B. Davidovich

“Conformational stabilization of isatin Schiff bases – biologically active chemical probes”

RSC Adv., 2017, 7, 10070-10073
DOI: 10.1039/c6ra26779c
источник: http://pubs.rsc.org/en/Content/ArticleLanding/2017/RA/C6RA26779C#!divAbstract

Isatin Schiff base derivatives have a wide range of biological effects. Unfortunately, these compounds possess a serious topological shortcoming: the conformational E ⇆ Z interconversion. Two ways of conformation stabilization are reported here: complexation with metals that stabilize the E-conformer and substitution in the 4th position of the isatin core stabilizing the Z-form.

Eur. J. Org. Chem., 2017, 2587-2595

A. Stukalov, V.V. Sokolov, V.V. Suslonov, M.A. Kuznetsov

“Pyrazoles and C-Imidoylaziridines through [4+1] Annulation and [2+1] Cycloaddition of 1-Azabuta-1,3-dienes with a Synthetic Equivalent of Phthalimidonitrene”

Eur. J. Org. Chem., 2017, 2587-2595
DOI: 10.1002/ejoc.201700172

Oxidative addition of N-aminophthalimide to 1,2,4-triaryl-1-azabuta-1,3-dienes leads, in most cases, to the regiodefined formation of 1,3,5-triarylpyrazoles in moderate to good yields through [4+1] annulation. This transformation is supposed to proceed by nitrenoid attack onto a lone pair of electrons of the imine nitrogen atom to give the vinylazomethine imine, followed by its 1,5-electrocyclization into pyrazoline and further aromatization into pyrazole. Rare examples of 2-imidoyl-1-phthalimidoaziridines that are formed by competitive [2+1] cycloaddition onto the C=C bond were isolated in low yields for 1-azadienes with electron-deficient aryl substituents at the imine nitrogen atom.

Tetrahedron Lett., 2017, 58, 172-174

M.A. Kuznetsov, A.N. Shestakov, M. Zibinsky, M. Krasavin, C.T. Supuran, S. Kalinin, Muhammet Tanç

“Synthesis, structure and properties of N-aminosaccharin — A selective inhibitor of human carbonic anhydrase I”

Tetrahedron Lett., 2017, 58, 172-174
DOI:10.1016/j.tetlet.2016.12.005

Previously unknown N-aminosaccharin was prepared in good yield via the one-step direct amination of saccharin sodium salt with hydroxylamine-O-mesitylenesulfonic acid (MSH) and its reactivity investigated. N-aminosaccharin and its derivatives were tested against hCA isoforms and the parent compound was identified to be a selective, low micromolar inhibitor (Ki = 8.8 μM) of hCA I. These findings provide a ligand-efficient starting point for the design of potent hCA I inhibitors – a promising drug target for retinal/cerebral edema treatment.

Tetrahedron, 2017, 73, 3939-3948

A.N. Shestakov, A.S. Pankova, P.Golubev, A.F. Khlebnikov, M.A. Kuznetsov

“Brønsted acid mediated cyclizations of ortho-aryl(ethynyl)pyrimidines”

Tetrahedron, 2017, 73, 3939-3948
DOI:10.1016/j.tet.2017.05.070
источник: http://www.sciencedirect.com/science/article/pii/S0040402017305719

A high-yielding procedure for the synthesis of 5-aryl-4-(arylethynyl)pyrimidines from easily available 2-aryl-3-hydroxyacrylates is reported. These pyrimidines readily undergo cyclization in strong Brønsted acids and, depending on the substitution in alkynylpyrimidines and the water content of the reaction mixture, yield either benzo[f]quinazolines or derivatives of spiro[cyclohexa-2,5-diene-1,5′-cyclopenta[d]pyrimidin]-4-one. In most cases the cyclization proceeds nearly quantitatively. DFT calculations support the proposed mechanisms induced by the protonation of the triple bond in 5-aryl-4-(arylethynyl)pyrimidines. Fluorescent properties of the obtained heterocycles are also described.

 

Неорганические Материалы, 2017, 53, 1-9

Е.А. Чалая, А.Г. Тюрин, М.В. Васеха, А.И. Бирюков, С.М. Сухаржевский

“Синтез и свойства двойного сульфита меди(I)–кобальта (II)”

Неорганические Материалы, 2017, 53(9), 1-9

источник: http://www.naukaran.com/zhurnali/katalog/neorganicheskie-materialy/

Уточнены диаграммы Пурбе систем Сu–Н2SO4–H2O и Co–H2SO4–H2O, в них определены области устойчивости сульфитных фаз. Построены диаграммы состояния двойных сульфитов меди(I)-меди(II), меди(I)-кобальта(II). Из водного раствора, насыщенного диоксидом серы, выделены двойные сульфиты: Cu2SO3 · СuSO3, Cu2SO3 · CoSO3. Получены спектры электронного парамагнитного резонанса, выполнены рентгенофазовый, ИК-спектроскопический, дисперсионный и термический анализы выделенного двойного сульфита CoSO3 · Cu2SO3. Заложена основа термодинамического прогнозирования синтеза двойных сульфитов состава Cu2SO3 · MSO3 (М – Cu, Co).

 

Geosciences, 2017, 7, 24

A. Lupachev, E. Abakumov, S. Gubin

“The Influence of Cryogenic Mass Exchange on the Composition and Stabilization Rate of Soil Organic Matter in Cryosols of the Kolyma Lowland (North Yakutia, Russia)”

Geosciences, 2017, 7, 24
DOI:10.3390/geosciences7020024

Источник: http://www.mdpi.com/2076-3263/7/2/24

Soil organic matter (SOM) was studied in different types of organo-mineral material (from surface horizons and partially isolated materials—cryoturbated or buried horizons) sampled from the surface horizons, the central parts of the Cryosol profiles, and the lower active layer. We found that the humic acids (HAs) of the cryoturbated and buried horizons showed an increased degree of oxidation and an increment of alkylaromatic and protonized aromatic fraction content. In contrast, the HAs of the surface horizons showed increased values of alkylic carbon components. The content of free radicals was essentially higher in the surface layers than in the cryoturbated and buried layers. While the bulk soil organic matter composition (total organic carbon, total nitrogen, and aromatic/aliphatic values) was not essentially different between surface, cryoturbated, and buried horizons, there were essential differences in elemental composition, carbon species, and free radical content. This indicates that the degree of humification in cryoturbated and buried organo-mineral material is higher than in surface horizons and that partial isolation results in relative stabilization of such material in soil profiles.

 

Оптика и Спектроскопия, 2017,122(3), 436-444

Е.А. Катленок, С.Н. Смирнов, А.Ю. Иванов, С.В. Макаренко, К.П. Балашев

“Влияние донорно-акцепторных свойств лигандов на спектроскопические и электрохимические характеристики смешанно-лигандных циклометаллированных комплексов Pt(II) и Ir(III) 2-фенилбензотиазола”

Оптика и Спектроскопия, 2017,122(3), 436-444
DOI:10.7868/S0030403417030126
Приведены результаты спектроскопических ЯМР 1Н, 13C, 195Pt, ИК, оптических и вольтамперометрических характеристик смешанно-лигандных комплексов Pt(II) и Ir(III) с металлированным 2-фенилбензотиазолом и трет-бутилизоцианидом (tBuNC), ацетонитрилом (AN), этилендиамином(En), О-этилдитиокарбонат- (Exn–) и диэтилдитиокарбонат-ионами (Dtc–). Показано, что изменение донорно-акцепторного взаимодействия с металлом лигандов tBuNC, AN, En, Exn–, Dtc– приводит к повышению энергии высшей заполненной молекулярной орбитали комплексов и сопровождается катодным смещением потенциала металл-центрированного окисления, батохромным смещением спин-разрешенного и спин-запрещенного оптических переходов переноса заряда металл-циклометаллированный лиганд и увеличением степени смешивания 1ПЗМЛ- и триплетного внутрилигандного состояния, ответственного за фосфоресценцию комплексов.

 

J. Wood Chem. Technol, 2017

E.I. Evstigneyev, A.V. Kalugina, A.Yu. Ivanov, A.V. Vasilyev

“Contents of α-o-4 and β-o-4 bonds in native lignin and isolated lignin preparations”

J. Wood Chem. Technol, 2017,accepted
DOI:10.1080/02773813.2017.1297832

An analytical calculation method for the estimation of the contents of alkyl aryl ether bonds (α-O-4 and β-O-4) in lignin was developed. In the framework of the method, Alkyl–O–Aryl type bonds are described as coupled phenolic hydroxyls (OHphen). The method is based on the balance equation including the free and coupled OHphen contents in dissolved and residual lignins, on the one hand, and their respective contents in native lignin, on the other. The free OHphen content is calculated on the basis of the OHphen contents of dissolved and residual lignin, determined by the aminolysis method in the course of kraft cooking of softwood. The calculation results for soluble lignin preparations are in good agreement with the 13C NMR (nuclear magnetic resonance) spectral data for the solutions. The content of Alkyl–O–Aryl bonds in native softwood (pine, spruce) lignin was estimated at 79/100 PPU (phenylpropane unit). In isolated lignin preparations, the contents of these bonds decrease in the sequence: Freudenberg lignin (71/100 PPU)> Bjorkman lignin (61/100 PPU)> Pepper lignin (44/100 PPU). Dissolved alkaline lignin still contains small amounts of Alkyl–O–Aryl bonds (36/100 PPU in soda lignin and an average of 23/100 PPU in soda-AQ lignin, kraft lignin, and kraft-AQ lignin). Residual lignin which represents the fraction of native lignin with inter-unit bonds resistant to kraft pulping contains 66/100 PPU of such bonds. A relatively high content of Alkyl–O–Aryl bonds (61/100 PPU) is preserved in technical hydrolysis lignins.

 

Известия РАН. Серия физическая, 2017, том 81, 344–348

Т. Н. Тарасенко, З. Ф. Кравченко, В. В. Бурховецкий, А. С. Мазур, В. И. Каменев, А. И. Линник

“Синтез, микроструктура, сложный характер магнитного состояния слаболегированного висмутом манганита лантана”

Известия РАН. Серия физическая, 2017, том 81, № 3, с. 344–348
DOI:10.7868/S036767651703036X

Проведены структурные, магнитные и резонансные исследования манганитов BixLa1 – xMnO3. Золь–гель-методом получены нанопорошки слаболегированных составов (x = 0.0–0.1) с размером частиц ≤40 нм. При спекании в одинаковых условиях средний размер гранул резко растет с ростом содержания Bi. Спектры ЯМР манганитов твердофазного синтеза 55Mn отвечают условию быстрого обмена Mn4+ ↔ Mn3+. Измерение магнитной восприимчивости обнаружило неоднородность магнитного состояния системы BixLa1 – xMnO3.

 

New J. Chem., 2017, 41, 316-325

Elena V. Andrusenko, Evgeniy V. Kabin, Alexander S. Novikov, Nadezhda A. Bokach, Galina L. Starova and Vadim Yu. Kukushkin

“Metal-mediated generation of triazapentadienate-terminated di- and trinuclear μ2-pyrazolate NiII species and control of their nuclearity”

New J. Chem., 2017, 41, 316-325
DOI:10.1039/C6NJ02962K
источник: http://pubs.rsc.org/

1,3,5-Triazapentadienate-terminated di- and trinuclear nickel(II) complexes featuring bridging azolate ligands, [Ni2(μ2-azolate)2(TAP)2] (TAP = H[N with combining low line][double bond, length as m-dash]C(OMe)NC(OMe)[double bond, length as m-dash][N with combining low line]H; azole = 3,5-Me2pyrazole 2, 3,5-Ph2pyrazole 3) and [Ni3(μ2-azolate)4(TAP)2] (azole = 3,5-Me2pyrazole 4, indazole 5), were obtained from systems Ni2+/NCNR2/azole systems in MeOH. The terminal TAP ligands in the [Ni2(μ2-azolate)2(TAP)2] and [Ni3(μ2-azolate)4(TAP)2] species originate from the previously unreported cascade NiII-mediated and chelation-driven reaction between cyanamides and methanol. The oligomeric species and also [Ni(TAP)2] (1) are subject to interconversions that depend on the reactants involved and the reaction conditions. The control of the nuclearity of the complexes can be achieved by changing the amount of azoles or by their protonation, alteration of the steric hindrance of the substituents in the heterocycles, and by changing the reaction temperature. Complexes 1–4 were characterized using elemental (C, H, N) analyses, 1H, 13C{1H} NMR, FTIR, HRESI-MS, TG-DTA, X-ray crystallography, and 5 was characterized using HRESI-MS and X-ray crystallography. Unconventional metallophilic contacts NiII⋯NiII were observed in dimer 3 in the solid state (the distance for Ni⋯Ni is 2.99 Å, whereas the double Bondi’s vdW radius for Ni is 3.26 Å) and the reality of these interactions was confirmed theoretically by the topological analysis of the electron density distribution (AIM method). The estimated energy for these non-covalent Ni⋯Ni interactions (ca. 4 kcal mol−1) fills the gap in the reported energies of the metal⋯metal interactions in a series comprising of NiII⋯NiII (this work), PdII⋯PdII (4.3–6.0 kcal mol−1), and PtII⋯PtII (3.9–11.7 kcal mol−1).