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91.
Alexandr V. Yatsenko Ksenia A. Paseshnichenko 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(8):961-964
The crystal structures of the brown–yellow and orange polymorphs of the title compound, 4‐[(2‐nitrophenyl)diazenyl]phenol, C12H9N3O3, have been determined and their visible reflection spectra recorded. Both structures adopt a stacking arrangement with interstack hydrogen bonds. Ab initio and semi‐empirical (AM1 and INDO‐CISD) calculations were performed in order to rationalize the difference in colour. It can be attributed neither to the subtle distinctions in molecular geometry nor to the effect of intermolecular electrostatic interactions. The most probable origin of this difference is the mixing of intramolecular n π* and intermolecular charge‐transfer excitations. 相似文献
92.
Alena L. Stalinskaya Nadezhda V. Martynenko Zarina T. Shulgau Alexandr V. Shustov Viktoriya V. Keyer Ivan V. Kulakov 《Molecules (Basel, Switzerland)》2022,27(12)
The COVID-19 pandemic is ongoing as of mid-2022 and requires the development of new therapeutic drugs, because the existing clinically approved drugs are limited. In this work, seven derivatives of epoxybenzooxocinopyridine were synthesized and tested for the ability to inhibit the replication of the SARS-CoV-2 virus in cell cultures. Among the described compounds, six were not able to suppress the SARS-CoV-2 virus’ replication. One compound, which is a derivative of epoxybenzooxocinopyridine with an attached side group of 3,4-dihydroquinoxalin-2-one, demonstrated antiviral activity comparable to that of one pharmaceutical drug. The described compound is a prospective lead substance, because the half-maximal effective concentration is 2.23 μg/μL, which is within a pharmacologically achievable range. 相似文献
93.
The Evens-Lu-Weinstein representation (Q
A
, D) for a Lie algebroid A on a manifold M is studied in the transitive case. To consider at the same time non-oriented manifolds as well, this representation is slightly
modified to (Q
A
or
, Dor) by tensoring by orientation flat line bundle, Q
A
or
=QA⊗or (M) and D
or=D⊗∂
A
or
. It is shown that the induced cohomology pairing is nondegenerate and that the representation (Q
A
or
, Dor) is the unique (up to isomorphy) line representation for which the top group of compactly supported cohomology is nontrivial.
In the case of trivial Lie algebroid A=TM the theorem reduce to the following: the orientation flat bundle (or (M), ∂
A
or
) is the unique (up to isomorphy) flat line bundle (ξ, ∇) for which the twisted de Rham complex of compactly supported differential
forms on M with values in ξ possesses the nontrivial cohomology group in the top dimension. Finally it is obtained the characterization
of transitive Lie algebroids for which the Lie algebroid cohomology with trivial coefficients (or with coefficients in the
orientation flat line bundle) gives Poincaré duality. In proofs of these theorems for Lie algebroids it is used the Hochschild-Serre
spectral sequence and it is shown the general fact concerning pairings between graded filtered differential ℝ-vector spaces:
assuming that the second terms live in the finite rectangular, nondegeneration of the pairing for the second terms (which
can be infinite dimensional) implies the same for cohomology spaces. 相似文献
94.
Dmitriy M VolochnyukAlexandr N Kostyuk Alexandr M PinchukAndrei A Tolmachev 《Tetrahedron letters》2003,44(2):391-394
5-Aminopyrazoles react with N-benzyl-3-cyanopyridinium chloride giving 1-benzyl-3-cyano-4-(5-aminopyrazol-4-yl)-1,4-dihydropyridines with high regioselectivity. 5-Aminoisoxazole, 2-aminothiazole and 6-aminouracil react analogously. 相似文献
95.
A simple method is suggested for the preparation of 5-alkylsulfinyl-1-aryltetrazoles via oxidation of 5-alkylsulfanyltetrazoles with 34% peracetic acid in high yields under mild conditions. 相似文献
96.
Nikolay A. Brusentsov Tatiana N. Brusentsova Elena Yu. Filinova Nikolay Y. Jurchenko Dmitry A. Kupriyanov Yuri A. Pirogov Andry I. Dubina Maxim N. Shumskikh Leonid I. Shumakov Ekaterina N. Anashkina Alexandr A. Shevelev Andry A. Uchevatkin 《Journal of magnetism and magnetic materials》2007
A dextran-ferrite magnetic fluid was successfully tested as magnetic resonance imaging (MRI) contrast agent. The same magnetic fluid was then combined with Melphalan, a chemotherapeutic drug, and used for magnetohydrodynamic thermochemotherapy of different tumors. The placement of the tumors in an AC magnetic field led to hyperthermia at 46 °C for 30 min. In combination with tumor slime aspiration, a 30% regression of ∼130 mm3 non-metastatic P388 tumors in BDF1 mice was reached, together with a life span increase of 290%. The same procedure associated with cyclophosphamide treatment of ∼500 mm3 metastases tumor increased the animal's life span by 180%. 相似文献
97.
We have observed that carbon deposits obtained by atomizing graphite in an electric arc in an atmosphere of argon and helium
exhibit porosity and possess fractal structure. The results of measurements of the internal friction Q
−1 and the effective Young’s modulus E as a function of temperature are presented. Data on the resistivity, density, and microhardness of the carbon deposits are
presented. A possible mechanism for formation of fractal structures in carbon deposits is discussed.
Fiz. Tverd. Tela (St. Petersburg) 40, 584–586 (March 1998) 相似文献
98.
Bezgin D. A. Ershov O. V. Ievlev M. Yu. Belikov M. Yu. Bardasov I. N. 《Russian Journal of Organic Chemistry》2018,54(7):1100-1102
Russian Journal of Organic Chemistry - Reactions of methoxybenzaldehydes with cyanoacetamide in water in the presence of cocamidopropylamine oxide afforded 84–94% of... 相似文献
99.
Rustem R. Amirov Asiya R. Mustafina Zuleikha T. Nugaeva Svetlana V. Fedorenko Ella Kh. Kazakova Alexandr I. Konovalov Wolf D. Habicher 《Journal of inclusion phenomena and macrocyclic chemistry》2004,49(3-4):203-209
The stoichiometry and binding constant of the paramagnetic lanthanide ion(Gd3+) with sulfonatomethylated calix[4]resorcinarene (H8Xna4) were evaluated from the NMR relaxation data. Both 1H NMR spectroscopy and NMR relaxation data indicate that interaction of tetramethylammonium (TEMA) and N-methylpyridinium (MePy) cations with H8Xna4 in the presence of Ln3+ (Lu3+ or Gd3+) results in theformation of ternary complexes [Ln(G)H8X] with lanthanide ions,coordinated via sulfonate groups and organic cation included intothe cavity of H8Xna4. The inclusion of long-chainedN-decyl-(DePy) and N-cetylpyridinium (CPy) ions into H8Xna4 cavity leads to self-assembling which can be revealed by NMR relaxation method with Gd3+ probe ions. The excess of alkylpyridinium or TEMA cations leads to disassembling of (Gd)n(H8X)m(RPy)maggregates. 相似文献
100.
Vadim A. Bataev Eugeniy K. Dolgov Alexandr V. Abramenkov Vladimir I. Pupyshev Igor A. Godunov 《International journal of quantum chemistry》2002,88(4):414-425
The potential energy surface (PES) for the CHF2CHO molecule in the excited S1 state is calculated by the CASSCF method. The features of the 1‐ and 2‐D cross‐sections of PES are considered in comparison with those of the relative molecules. The vibrational frequencies are calculated in harmonic approximation and the vibrational energy levels for the inversion motion of the carbonyl fragment CCHaO and for the torsion motion of the CHF2‐top are calculated in anharmonic approximation by the 1‐ and 2‐D variational methods. The calculated data are compared with the experimental ones. The problems of the experimental data interpretation are considered. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002 相似文献