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71.
Alexander A. Simenel Galina A. Dokuchaeva Lubov' V. Snegur Alexey N. Rodionov Mikhail M. Ilyin Svetlana I. Zykova Larissa A. Ostrovskaya Natalia V. Bluchterova Margarita M. Fomina Valentina A. Rikova 《应用有机金属化学》2011,25(1):70-75
Ferrocenylalkyl thiopyrimidines ( 6a–d to 9a–d ) were prepared via the reaction of the α‐(hydroxy)alkyl ferrocenes, FcCHR(OH) ( 1a–d ; Fc = ferrocenyl; R = H, Me, Et, Ph), with 2‐thiopyrimidines ( 2 – 5 ) in acetone at room temperature in the presence of TFA, yielding 50–95%. The resulting enantiomers were resolved using HPLC on modified cellulose as chiral selector. The antitumor activities of S‐ferrocenylethyl 2‐thiopyrimidine ( 6b ) against two murine solid tumor models, carcinoma 755 (Ca755) and Lewis lung carcinoma (LLC) were evaluated in vivo. The strong antitumor effect of compound 6b on Ca755 and LLC was demonstrated. The index of tumor growth inhibition on Ca755 equaled 95% in comparison with control. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
72.
Christine Bernardi Marie-Claude Pelissier 《Finite Elements in Analysis and Design》1994,16(3-4):309-315
Paraxial approximation to the Helmholtz equation in ocean acoustic leads to solve a mixed Schrödinger boundary-value problem. The numerical analysis is performed combining a spectral method in the depth direction and a leap-frog scheme in the propagation direction. A convergence analysis for the approximation is developed, providing error estimates. 相似文献
73.
JPC – Journal of Planar Chromatography – Modern TLC - Anew OPLC method has been established for separation and quantitative determination of three alditols (d-xylitol, L-arabitol, and... 相似文献
74.
Enrico Bernardi 《Annali di Matematica Pura ed Applicata》1986,146(1):161-172
Summary We study a class of second order Fuchsian hyperbolic operators. The well-posedness of the Cauchy problem in a space of regular distributions is proved, together with results on the propagation of singularities of the solution. Moreover we give a representation formula for the distribution solutions of the homogeneous equation. 相似文献
75.
Francesca Bernardi Shankararaman Chellam N. G. Cogan M. N. J. Moore 《Studies in Applied Mathematics》2023,151(1):116-140
We derive a class of exact solutions for Stokes flow in infinite and semi-infinite channel geometries with permeable walls. These simple, explicit, series expressions for both pressure and Stokes flow are valid for all permeability values. At the channel walls, we impose a no-slip condition for the tangential fluid velocity and a condition based on Darcy's law for the normal fluid velocity. Fluid flow across the channel boundaries is driven by the pressure drop between the channel interior and exterior; we assume the exterior pressure to be constant. We show how the ground state is an exact solution in the infinite channel case. For the semi-infinite channel domain, the ground-state solutions approximate well the full exact solution in the bulk and we derive a method to improve their accuracy at the transverse wall. This study is motivated by the need to quantitatively understand the detailed fluid dynamics applicable in a variety of engineering applications including membrane-based water purification, heat and mass transfer, and fuel cells. 相似文献
76.
Dr. Natalie Spomer Dr. Sven Holl Dr. Larissa Zherlitsyna Dr. Fariba Maysamy Andreas Frost Prof. Dr. Norbert Auner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5600-5616
Amorphous silicon is synthesized by treating the tetrahalosilanes SiX4 (X=Cl, F) with molten sodium in high boiling polar and non‐polar solvents such as diglyme or nonane to give a brown or a black solid showing different reactivities towards suitable reagents. With regards to their technical relevance, their stability towards oxygen, air, moisture, chlorine‐containing reaction partners RCl (R=H, Cl, Me) and alcohols is investigated. In particular, reactions with methanol are a versatile tool to deliver important products. Besides tetramethoxysilane formation, methanolysis of silicon releases hydrogen gas under ambient conditions and is thus suitable for a decentralized hydrogen production; competitive insertion into the MeO?H versus the Me?OH bond either yields H‐ and/or methyl‐substituted methoxy functional silanes. Moreover, compounds, such as MenSi(OMe)4?n (n=0–3) are simply accessible in more than 75 % yield from thermolysis of, for example, tetramethoxysilane over molten sodium. Based on our systematic investigations we identified reaction conditions to produce the methoxysilanes MenSi(OMe)4?n in excellent (n=0:100 %) to acceptable yields (n=1:51 %; n=2:27 %); the yield of HSi(OMe)3 is about 85 %. Thus, the methoxysilanes formed might possibly open the door for future routes to silicon‐based products. 相似文献
77.
Catalytic Asymmetric Reactions of 4‐Substituted Indoles with Nitroethene: A Direct Entry to Ergot Alkaloid Structures
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Simone Romanini Emilio Galletti Dr. Lorenzo Caruana Prof. Andrea Mazzanti Prof. Fahmi Himo Dr. Stefano Santoro Prof. Mariafrancesca Fochi Prof. Luca Bernardi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(49):17578-17582
A domino Friedel–Crafts/nitro‐Michael reaction between 4‐substituted indoles and nitroethene is presented. The reaction is catalyzed by BINOL‐derived phosphoric acid catalysts, and delivers the corresponding 3,4‐ring‐fused indoles with very good results in terms of yields and diastereo‐ and enantioselectivities. The tricyclic benzo[cd]indole products bear a nitro group at the right position to serve as precursors of ergot alkaloids, as demonstrated by the formal synthesis of 6,7‐secoagroclavine from one of the adducts. DFT calculations suggest that the outcome of the reaction stems from the preferential evolution of a key nitronic acid intermediate through a nucleophilic addition pathway, rather than to the expected “quenching” through protonation. 相似文献
78.
The problem of the determination of the free oscillation modes of a cavity resonator completely filled with magnetized ferrite is considered. A first order formulation, which takes into account the equation of motion of the magnetization vector together with Maxwell's equations, is used. By expanding the field vectors in terms of solenoidal and irrotational eigenfunctions of the corresponding empty resonator, a matrix eigenvalue problem in classical form is obtained. The general formulation is specialized to the particular case of a circularly cylindrical resonator filled with transversely magnetized ferrite. A numerical analysis for the determination of resonance frequencies and field configurations is carried out.Work partially supported by Consiglio Nazionale delle Ricerche of Italy. 相似文献
79.
Vinícius D. Araújo Waldir Avansi Elaine C. Paris Lauro J. Q. Maia Maria I. B. Bernardi 《Journal of Sol-Gel Science and Technology》2011,59(3):488-494
Pb2CrO5 nanoparticles were embedded in an amorphous SiO2 matrix by the sol–gel process. The pH and heat treatment effects were evaluated in terms of structural, microstructural and
optical properties from Pb2CrO5/SiO2 compounds. X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), energy dispersive spectroscopy
(EDS), and diffuse reflectance techniques were employed. Kubelka–Munk theory was used to calculate diffuse reflectance spectra
that were compared to the experimental results. Finally, colorimetric coordinates of the Pb2CrO5/SiO2 compounds were shown and discussed. In general, an acid pH initially dissolves Pb2CrO5 nanoparticles and following heat treatment at 600 °C crystallized into PbCrO4 composition with grain size around 6 nm in SiO2 matrix. No Pb2CrO5 solubilization was observed for basic pH. These nanoparticles were incorporated in silica matrix showing a variety of color
ranging from yellow to orange. 相似文献
80.
Zenkevich IG Eliseenkov EV Kasatochkin AN Zhakovskaya ZA Khoroshko LO 《Journal of chromatography. A》2011,1218(21):3291-3299
Chlorinated derivatives of aliphatic ketones are a class of organic compounds poorly characterized by both mass spectra and chromatographic retention indices up to present. It is caused by objective difficulties of isolation of individual products from reaction mixtures formed in the result of non-selective chlorination of parent carbonyl compounds. Nevertheless the differences of GC retention indices for structurally analogous chlorination products of different ketones and initial substrates indicate the constancy depending on the number and position of chlorine atoms in the molecules. This feature permits us to use the simplest kind of additive schemes in identification of such chlorinated derivatives, including diastereomeric α,α'-dichloro-k-alkanones (k>2). Hence, the identification of chlorination products of aliphatic ketones becomes possible for any compounds of this class without using mass spectrometric data only in the result of accurate measurement of their GC retention indices. 相似文献