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91.
Olivier Russo Abdallah Hamze Nathanäel Olivi Jean-Daniel Brion Sames Sicsic Isabelle Berque-Bestel Mouâd Alami 《Tetrahedron》2007,63(43):10671-10683
An efficient palladium-copper-catalyzed three-component assembling of propargyl halides, aryl or heteroaryl halides, and secondary amines is described. A wide variety of tertiary propargylic amines were synthesized in good to excellent yields from easily accessible starting materials. This three-component assembling was also effective when using potassium phthalimide or di-tert-butyliminodicarbonate instead of secondary amines. Consequently, it provides a quick entry to N-protected propargylic amines suitable intermediates for the synthesis of primary and secondary propargylic amines. In a similar way, related compounds including propargylic amide, carbamate and sulfonamide derivatives were efficiently obtained. This catalytic domino three-component process has been applied successfully to the construction of functionalized 2-(aminomethyl)benzo[b]furan or indole derivatives of biological interest. 相似文献
92.
Enzymophoresis with coupled heterogeneous capillary enzyme reactor-capillary zone electrophoresis was developed and evaluated in the area of nucleic acids. Ribonuclease T1, hexokinase and adenosine deaminase were successfully immobilized on the inner walls of short fused-silica capillaries through glutaraldehyde attachment. These open-tubular capillary enzyme reactors were quite stable for a prolonged period of use under operation conditions normally used in capillary zone electrophoresis. The capillary enzyme reactors coupled in series with capillary zone electrophoresis served as peak locator on the electropherogram, improved the system selectivity, and facilitated the quantitative determination of the analytes with good accuracy. Also, they allowed the on-line digestion and mapping of minute amounts of transfer ribonucleic acids, and the simultaneous synthesis and separation of nanogram quantities of oligonucleotides. 相似文献
93.
The determination of trace elements in the various stages of the water cycle is very important. Economic procedures for multi-element determinations of trace elements in various matrices are needed. The applications of total-reflection x-ray fluorescence spectrometry in this general area are reviewed briefly, with examples relating to rain, river and sea waters, sediments, particulate matter and manganese nodules and crusts, as well as mussel tissue. Up to 25 elements can be determined; these are S, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Pb, Se, Rb, Sr, Y, Zr, Mo, Ag, Cd, Sb and Ba. Preliminary treatments of the various matrices are described. Accuracy checks by analysis of reference standards and by application of independent techniques are reported. 相似文献
94.
Carella A Jaud J Rapenne G Launay JP 《Chemical communications (Cambridge, England)》2003,(19):2434-2435
A short route to prepare a ruthenium complex with a pentaphenyl substituted cyclopentadienyl and a hydrotris(indazolyl)borate ligand is described: this complex can be seen as an organometallic molecular turnstile. 相似文献
95.
96.
Michał Padjasek Dr. Maciej Maciejczyk Dr. Michał Nowakowski Olga Kerber Maciej Pyrka Prof. Dr. Wiktor Koźmiński Prof. Dr. Artur Krężel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(15):3297-3313
CdII is a major genotoxic agent that readily displaces ZnII in a multitude of zinc proteins, abrogates redox homeostasis, and deregulates cellular metalloproteome. To date, this displacement has been described mostly for cysteine(Cys)-rich intraprotein binding sites in certain zinc finger domains and metallothioneins. To visualize how a ZnII-to-CdII swap can affect the target protein's status and thus understand the molecular basis of CdII-induced genotoxicity an intermolecular ZnII-binding site from the crucial DNA repair protein Rad50 and its zinc hook domain were examined. By using a length-varied peptide base, ZnII-to-CdII displacement in Rad50’s hook domain is demonstrated to alter it in a bimodal fashion: 1) CdII induces around a two-orders-of-magnitude stabilization effect (log =20.8 vs. log =22.7), which defines an extremely high affinity of a peptide towards a metal ion, and 2) the displacement disrupts the overall assembly of the domain, as shown by NMR spectroscopic and anisotropy decay data. Based on the results, a new model explaining the molecular mechanism of CdII genotoxicity that underlines CdII’s impact on Rad50’s dimer stability and quaternary structure that could potentially result in abrogation of the major DNA damage response pathway is proposed. 相似文献
97.
Selenium‐Catalyzed C(sp3)H Acyloxylation: Application in the Expedient Synthesis of Isobenzofuranones 下载免费PDF全文
Felix Krätzschmar Martin Kaßel Daniel Delony Dr. Alexander Breder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(19):7030-7034
Oxidative Se‐catalyzed C(sp3)?H bond acyloxylation has been used to construct a diverse array of isobenzofuranones from simple ortho‐allyl benzoic acid derivatives. The synthetic procedure employs mild reaction conditions and gives high chemoselectivity enabled by an inexpensive organodiselane catalyst. The presented approach offers a new synthetic pathway toward the core structures of phthalide natural products. 相似文献
98.
Miloslav Hartman Karel Svoboda Michael Pohořelý Michal Šyc Siarhei Skoblia Yau-Pin Chyou 《Chemical Papers》2017,71(3):563-577
Sorption of hydrogen chloride gas by active soda and that of hydrogen sulfide gas by calcium oxide are explored by experiment as promising means of removing these detrimental contaminants from fuel gas: active Na2CO3 was prepared by the calcination of commercial NaHCO3 at 200 °C; reactive CaO was formed by decomposing a fine-grained, high-calcium limestone at 830 °C. Techniques with a differential reactor were employed to explore the rate of reaction of HCl with Na2CO3 at 500 °C and that of H2S with CaO at 800 °C. Time-resolved data on the sorbents’ conversion were collected as a function of mean particle size in the range between 0.285 and 1.12 mm. The surface reaction constants, deduced via the tractable model from the initial reaction rates of the two reactions, slightly increase with the increasing particle size. The proposed correlations enable to interpolate or cautiously extrapolate to other isotropic, irregularly shaped solids. The effective diffusivities educed by means of the model from the experimental curves decrease significantly with the increasing conversion and are affected by the particle size in both sorptions. The developed reaction rate equations can conveniently be applied to the design and simulation of the deep dechloridization and the bulk desulfurization of hot producer gas. 相似文献
99.
100.
Nel Lohou 《Mathematische Nachrichten》2006,279(3):272-298
On montre des estimées pour le projecteur de De Rham–Hodge. We prove estimates for the De Rham–Hodge Lp projectors. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献