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71.
72.
Martin Vuagnat Dr. Vincent Tognetti Prof. Dr. Philippe Jubault Dr. Tatiana Besset 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(55):e202201928
In this study, a practical and straightforward synthesis of β-(E)-trifluoromethylstyrenes by ruthenium-catalyzed C−H bond activation was developed. The readily available and inexpensive 2-bromo-3,3,3-trifluoropropene (BTP), a non-ozone depleting reagent, was used as a reservoir of 3,3,3-trifluoropropyne. With this approach, the monofunctionalization of a panel of heteroarenes was possible in a safe and scalable manner (23 examples, up to 87 % yield). Mechanistic investigations and density functional theory (DFT) calculations were also conducted to get a better understanding of the mechanism of this transformation. These studies suggested that 1) a cyclometallated ruthenium complex enabled the transformation, 2) this complex exhibited high efficiency in this transformation compared to the commercially available [RuCl2(p-cymene)]2 and 3) the mechanism proceeded through a bis-cyclometallated ruthenium intermediate for the carboruthenation step. 相似文献
73.
Sapozhnikova Irina M. Ulomsky Evgeny N. Rusinov Vladimir L. Chupakhin Oleg N. Stepanov Alexander V. Savateeva-Lyubimova Tatiana N. Sivak Konstantin V. 《Chemistry of Heterocyclic Compounds》2021,57(4):467-472
Chemistry of Heterocyclic Compounds - A series of azolo[5,1-c][1,2,4]triazines containing a cyano group were prepared as analogs of the drug Triazavirin (riamilovir). Sodium... 相似文献
74.
Dr. Tatiana Suárez-Rodríguez Prof. Dr. Ángel L. Suárez-Sobrino Prof. Dr. Alfredo Ballesteros 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(51):13079-13084
Gold(I)-catalyzed formal [4+2] cycloaddition of O-aryl ynol ethers 1 and enol ethers 2 is described. This intermolecular reaction between two electron-rich unsaturated systems takes place, under mild conditions, in the presence of 5 mol% [IPrAu(CH3CN)]SbF6 as catalyst giving chromene derivatives with good yields. The cycloaddition is completely regio- and stereoselective, as well as versatile for both reactives. Silyl enol ethers can also react in the same way and under the same reaction conditions with quantitative yields. A plausible mechanism through a selective addition of the enol ether to the alkyne gold activated complex followed by an intramolecular aromatic electrophilic substitution is proposed. Several experimental results support the presence of a cationic oxonium intermediate prior to the aromatic substitution. The reaction represents a new entry to the chromene core. 相似文献
75.
Tatiana Chernogorova Radoslav Valkov 《Numerical Methods for Partial Differential Equations》2015,31(3):822-846
We consider the locally one‐dimensional backward Euler splitting method to solve numerically the Hull and White problem for pricing European options with stochastic volatility in the presence of a mixed derivative term. We prove the first‐order convergence of the time‐splitting. The parabolic equation degenerates on the boundary x = 0 and we apply a fitted finite volume scheme to the equation to resolve the degeneracy and derive the fully discrete problem as we also investigate the discrete maximum principle. Numerical experiments illustrate the efficiency of our difference scheme. © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 31: 822–846, 2015 相似文献
76.
Tatiana Moskalets Alexei Nurmagambetov 《The European Physical Journal C - Particles and Fields》2015,75(11):551
We establish solutions corresponding to AdS\(_4\) static charged black holes with inhomogeneous two-dimensional horizon surfaces of constant curvature. Depending on the choice of the 2D constant curvature space, the metric potential of the internal geometry of the horizon satisfies the elliptic wave/elliptic Liouville equations. We calculate the charge diffusion and transport coefficients in the hydrodynamic limit of gauge/gravity duality and observe the exponential suppression in the diffusion coefficient and in the shear viscosity-per-entropy density ratio in the presence of an inhomogeneity on black hole horizons with planar, spherical, and hyperbolic geometry. We discuss the subtleties of the approach developed for a planar black hole with inhomogeneity distribution on the horizon surface in more detail and find, among others, a trial distribution function, which generates values of the shear viscosity-per-entropy density ratio falling within the experimentally relevant range. The solutions obtained are also extended to higher-dimensional AdS space. We observe two different DC conductivities in 4D and higher-dimensional effective strongly coupled dual media and formulate conditions under which the appropriate ratio of different conductivities is qualitatively the same as that observed in an anisotropic strongly coupled fluid. We briefly discuss ways of how the Liouville field could appear in condensed matter physics and outline prospects of further employing the gauge/gravity duality in CMP problems. 相似文献
77.
Recent Progress in Direct Introduction of Fluorinated Groups on Alkenes and Alkynes by means of CH Bond Functionalization 下载免费PDF全文
Dr. Tatiana Besset Dr. Thomas Poisson Prof. Xavier Pannecoucke 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(51):16830-16845
The direct introduction of fluorine and fluorinated building blocks has recently attracted a lot of attention and particularly the direct functionalization of alkenes and alkynes. This review will highlight the major progress recently made in that field, with a focus on photocatalyzed transformations, base‐promoted processes, and transition metal‐catalyzed functionalization of alkenes and alkynes. Special attention will be paid to explanations of the reaction mechanisms. 相似文献
78.
Dr. Aleksandr M. Agafontsev Dr. Tatiana A. Shumilova Dr. Aleksandr S. Oshchepkov Dr. Frank Hampel Prof. Dr. Evgeny A. Kataev 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(44):9991-9997
Pyrene-based cyclophanes have been synthesized with the aim to realize a bellows-type sensing mechanism for the ratiometric detection of nucleotide concentrations in a buffered aqueous solution. The sensing mechanism involves the encapsulation of a nucleobase between two pyrene rings, which affects the monomer-excimer equilibrium of the receptor in the excited state. The nature of the spacer and its connection pattern to pyrene rings have been varied to achieve high selectivity for ATP. The 1,8-substituted pyrene-based cyclophane with the 2,2’-diaminodiethylamine spacer demonstrates the best selectivity for ATP showing a 50-fold increase in the monomer-excimer emission ratio upon saturation with the nucleotide. The receptor can detect ATP within the biological concentrations range over a wide pH range. NMR and spectroscopic studies have revealed the importance of hydrogen bonding and stacking interactions for achieving a required receptor selectivity. The probe has been successfully applied for the real-time monitoring of creatine kinase activity. 相似文献
79.
Xiaobo Qu Yihui Huang Hengfa Lu Tianyu Qiu Di Guo Tatiana Agback Vladislav Orekhov Zhong Chen 《Angewandte Chemie (International ed. in English)》2020,59(26):10297-10300
Nuclear magnetic resonance (NMR) spectroscopy serves as an indispensable tool in chemistry and biology but often suffers from long experimental times. We present a proof‐of‐concept of the application of deep learning and neural networks for high‐quality, reliable, and very fast NMR spectra reconstruction from limited experimental data. We show that the neural network training can be achieved using solely synthetic NMR signals, which lifts the prohibiting demand for a large volume of realistic training data usually required for a deep learning approach. 相似文献
80.
Ganeeva Yulia M. Yusupova Tatiana N. Okhotnikova Ekaterina S. 《Journal of Thermal Analysis and Calorimetry》2020,139(1):273-278
Journal of Thermal Analysis and Calorimetry - The bitumen-containing reservoir rocks taken from Devonian terrigenous formation of Romashkino and Bavly oil fields (Russia) were sampled and... 相似文献