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131.
Kayukov Ya. S. Karpov S. V. Kayukova O. V. Grigor’ev A. A. 《Russian Journal of Organic Chemistry》2020,56(7):1313-1316
Russian Journal of Organic Chemistry - The reaction of 4-acyl-2-amino-6-chloropyridine-3,5-dicarbonitriles with aromatic thiols in 1,4-dioxane in the presence of triethylamine led to the formation... 相似文献
132.
Alexander S. Antonov Elena Yu Tupikina Valerii V. Karpov Valeriia V. Mulloyarova Victor G. Bardakov 《Molecules (Basel, Switzerland)》2020,25(24)
The influence of steric repulsion between the NMe2 group and a second ortho-(peri-)substituent in the series of 1-dimethylaminonaphthalene and N,N-dimethylanilene ortho-oximes on the ease of the NMe2 group’s intramolecular nucleophilic substitution is studied. Possible reaction intermediates for three mechanisms are calculated (ωB97xd/def-2-TZVP), and their free Gibbs energies are compared to model reaction profiles. Supporting experiments have proved the absence of studied reactivity in the case of simple 2-dimethylaminobenzaldoxime, which allowed us to establish reactivity limits. The significant facilitation of NMe2 group displacement in the presence of bulky substituents is demonstrated. The possibility of fused isoxazoles synthesis via the intramolecular nucleophilic substitution of a protonated NMe2 group in the aniline and naphthalene series is predicted. 相似文献
133.
Bobrovnitskii Yu. I. Tomilina T. M. Bakhtin B. N. Grebennikov A. S. Asfandiyarov S. A. Karpov I. A. Kim A. A. 《Acoustical Physics》2020,66(3):324-332
Acoustical Physics - The article describes an experimental facility for studying and testing sound-absorbing linings made of acoustic metamaterials designed to reduce the noise generated by a... 相似文献
134.
Nanofluidics encompasses a wide range of advanced approaches to study charge and mass transport at the nanoscale. Modern technologies allow us to develop and improve artificial nanofluidic platforms that confine ions in a way similar to single-ion channels in living cells. Therefore, nanofluidic platforms show great potential to act as a test field for theoretical models. This review aims to highlight ionic Coulomb blockade (ICB)—an effect that is proposed to be the key player of ion channel selectivity, which is based upon electrostatic exclusion limiting ion transport. Thus, in this perspective, we focus on the most promising approaches that have been reported on the subject. We consider ion confinements of various dimensionalities and highlight the most recent advancements in the field. Furthermore, we concentrate on the most critical obstacles associated with these studies and suggest possible solutions to advance the field further. 相似文献
135.
Dzmitry Padhorny David R. Hall Hanieh Mirzaei Artem B. Mamonov Mohammad Moghadasi Andrey Alekseenko Dmitri Beglov Dima Kozakov 《Journal of computer-aided molecular design》2018,32(1):225-230
Fast Fourier transform (FFT) based approaches have been successful in application to modeling of relatively rigid protein–protein complexes. Recently, we have been able to adapt the FFT methodology to treatment of flexible protein–peptide interactions. Here, we report our latest attempt to expand the capabilities of the FFT approach to treatment of flexible protein–ligand interactions in application to the D3R PL-2016-1 challenge. Based on the D3R assessment, our FFT approach in conjunction with Monte Carlo minimization off-grid refinement was among the top performing methods in the challenge. The potential advantage of our method is its ability to globally sample the protein–ligand interaction landscape, which will be explored in further applications. 相似文献
136.
137.
Marina A. Katkova Galina S. Zabrodina Evgeny V. Baranov Maria S. Muravyeva Evgeny A. Kluev Andrey S. Shavyrin Grigory Yu Zhigulin Sergey Yu Ketkov 《应用有机金属化学》2018,32(7)
The development of contrast agents specifically designed for high‐field magnetic resonance imaging (MRI) is required because the relaxation efficiency of classic Gd(III) contrast agents significantly decreases with increasing magnetic field strengths. With an idea of exploring the unique structure of lanthanide (Ln) 15‐MC‐5 metallacrowns, we developed a series of water‐soluble Gd(III) aqua‐complexes, bearing aminohydroxamate (glycine, α‐alanine, α‐phenylalanine and α‐tyrosine) ligands, with increasing number of water molecules directly coordinated to the Gd(III) ion: Gd(H2O)4[15‐MCCu(II)Glyha‐5](Cl)3 ( 1 (Gd)), Gd(H2O)4[15‐MCCu(II)Alaha‐5](Cl)3 ( 2 (Gd)), Gd(H2O)3[15‐MCCu(II)Phalaha‐5](Cl)3 ( 3 (Gd)) and Gd(H2O)3[15‐MCCu(II)Tyrha‐5](Cl)3 ( 4 (Gd)). In these systems, the Ln(III) central ion is coordinated by five oxygen donor atoms of the ligands and three or four inner‐sphere water molecules. The X‐ray crystal structure of metallacrown Ln(H2O)3,4[15‐MCCu(II)Rha‐5]3+ agrees with density functional theory predictions. The calculations demonstrate that the exchange of coordinated water molecules can proceed easily, resulting in increased relaxivity parameters. The longitudinal relaxivities (r1) of 1 (Gd)– 4 (Gd) in water at ultrahigh magnetic field of 9.4 T were determined to be 11.5, 14.8, 13.9 and 12.2 mM?1 s?1, respectively. The ability to increase the number of Ln(III) inner‐sphere water molecules up to four, the planar metallacrown structure and the rich hydration shell due to strong hydrogen bonds between the [15‐MC‐5] moiety and bulk water molecules provide new opportunities for potential MRI applications. 相似文献
138.
Zhen Ye Chong Lin Andrey E. Barabanov 《Journal of Mathematical Analysis and Applications》2007,334(1):28-42
In this paper, a class of second-order servo plants under relay feedback is studied. Complete results on the uniqueness of solutions, existence and stability of the limit cycles are established using the point transformation method. And a numerical method is developed for determining the amplitude and period of a stable limit cycle from the plant parameters. 相似文献
139.
One of modern approaches to the problem of coordination of classical mechanics and statistical physics — functional mechanics
is considered. Deviations from classical trajectories are calculated and evolution of themoments of distribution function
is constructed. The relation between the received results and absence of the Poincaré-Zermelo paradox in functional mechanics
is discussed. Destruction of periodicity of movement in functional mechanics is shown and decrement of attenuation for classical
invariants of movement on a trajectory of functional mechanical averages is calculated. 相似文献
140.
Denis A. Knyazkov Artëm M. Dmitriev Oleg P. Korobeinichev Ksenia N. Osipova Gianmaria Pio Andrey G. Shmakov Ernesto Salzano 《Proceedings of the Combustion Institute》2021,38(2):2467-2475
The knowledge of the combustion chemistry of oxygenated fuels is essential for the development of detailed kinetic mechanisms suitable for the combustion processes involving biofuels. Moreover, epoxidized olefins, are increasingly used as chemical intermediates or as bulk chemicals. Nevertheless, a dearth of data for their reactivity in the oxidative environment can be observed in the current literature. This study reports the experimental and the model characterization of the flame structure of propylene oxide at stoichiometric and fuel-rich conditions at atmospheric pressure. To this aim, the species mole fractions in three premixed flames stabilized on a flat-flame burner have been quantitatively measured by using the flame sampling molecular beam mass spectrometry. Three chemical kinetic mechanisms retrieved from the current literature involving propylene oxide chemistry have been validated against the novel experimental data. In general, the predictions appeared to be in satisfactory agreement with measurements except for acetaldehyde and ketene. The rate of production analysis in the flame has shown that the discrepancies observed for these species are related basically to the incorrect ratio between the rates of primary reaction pathways of propylene oxide destruction. 相似文献