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排序方式: 共有849条查询结果,搜索用时 15 毫秒
751.
Stanetty P Hattinger G Schnürch M Mihovilovic MD 《The Journal of organic chemistry》2005,70(13):5215-5220
A novel, short, and efficient synthetic pathway to 3-{4-[2-(3-chlorophenylamino)-pyrimidin-4-yl]-pyridin-2-ylamino}-propanol (CGP 60474) and a series of analogues was developed. The synthetic sequence consisted of a Negishi-type cross-coupling reaction in the key step followed by two subsequent nucleophilic substitution reactions. This strategy represents a versatile and robust protocol to access diverse analogues of the title compound for subsequent SAR studies as potential phenylamino-pyrimidine type protein kinase C inhibitors. 相似文献
752.
Hamid Reza Nasiri M. Gregor Madej C. Roy D. Lancaster Harald Schwalbe Michael Bolte 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(12):o671-o673
The title compound, C14H12O4, forms crystals which appear monoclinic but are actually twinned triclinic. The asymmetric unit consists of two similar molecules, which differ only in the conformation of the 3‐oxobutyl side chain. The molecular conformation is characterized by an intramolecular O—H⋯O hydrogen bond between the hydroxy group and the adjacent carbonyl O atom. The crystal structure is stabilized by O—H⋯O hydrogen bonds connecting the molecules into zigzag chains running along the b axis. 相似文献
753.
Negative chemical ionization mass spectrometry is used as a probe to examine reactions between hydrocarbon radicals and metal complexes in the gas phase. The methane negative chemical ionization mass spectra of 27 complexes of cobalt(II ), nickel(II ) and copper(II ) in the presence of O4, O2N2 and N4 donor atom sets are characterized by two dominant series of adduct ions of the form [M + CnH2n]? and [M + CnH2n+1]? at m/z values above the molecular ion, [M]?. Insertion of the CH radical into the ligand followed by radical/radical recombination and electron capture is proposed as the major mechanism leading to the formation of [M + CnH2n]? adduct ions. A second pathway involves ligand substitution by CnH2n+1 radicals concomitant with H elimination and electron capture. Oxidative addition at the metal followed by ionization is suggested as the principal pathway for the formation of [M + CnH2n+1]? adduct ions. 相似文献
754.
Gregor Högenauer 《Monatshefte für Chemie / Chemical Monthly》1967,98(2):494-500
Zusammenfassung Für ein neues Verfahren zur Untersuchung von Codon—Anticodon-Wechselwirkungen wurden radioaktive Trinukleotide mit möglichst hohen spezif. Aktivitäten im Milligrammaßstab benötigt. Zu ihrer Gewinnung wurde ausE. coli und Bäckerhefe, die in32P-phosphathältigen Nährmedien gezüchtet worden waren, die Gesamt-RNA isoliert und enzymatisch hydrolysiert. Das dabei entstandene Oligonukleotidgemisch wurde durch Papierchromatographie und Elektrophorese aufgetrennt, wobei elf markierte Trinukleotide in reiner Form erhalten werden konnten.
Mit 3 Abbildungen 相似文献
For the study of codon-anticodon interactions radioactive trinucleotides with high specific activities had to be prepared in milligram quantities. Labelled RNA was obtained fromE. coli and baker's yeast grown in a medium containing32P-phosphate. The RNA was hydrolyzed with enzymes and the resulting oligonucleotide mixture separated by paper chromatography and electrophoresis. Eleven pure, labelled trinucleotides were isolated by this procedure.
Mit 3 Abbildungen 相似文献
755.
Malcolm H. Mac Gregor 《Foundations of Physics Letters》1995,8(2):135-160
From the perspective of physical realism (PR), a photon is a localized entity that carries energy and momentum, and which is surrounded by a wave packet (anempty wave) that is devoid of observable energy or momentum. In creating quantized PR basis states for a photon wave packet, three requirements must be met:(1) The basis states must each carry the frequency of the wave;(2) They must closely resemble the photon, so that e.g. they scatter in the same manner from an optical mirror;(3) They must have infinitesimal energy, linear momentum, and angular momentum. An essentially zero-energy "empty wave" quantum-a "zeron"-is defined which meets these requirements. It is created as an asymmetric single-particle (or single-antiparticle) excitation of the vacuum state, with the "particle" (or "antiparticle") and its associated "hole" (or "antihole") forming a rotational bound state. The photon is reproduced as a symmetric particle-antiparticle excitation of the vacuum state, with the "particle" and "antiparticle" also forming a rotational bound state. The relativistic transformation problem is discussed. A key point in this development is the deduction of the correct equation of motion for a "hole" state in an external electrostatic field. 相似文献
756.
Martina Sandholzer Alexandra Lex Gregor Trimmel Robert Saf Franz Stelzer Christian Slugovc 《Journal of polymer science. Part A, Polymer chemistry》2007,45(7):1336-1348
A convenient synthetic route towards polymerizable fluorescein, dicholorofluorescein, and eosin dyes is presented. Polymerizability was provided by linking 2‐norbornene carboxylic acid, 11‐bromo‐undecyl ester to the dye's carboxylate functionality. Although the monomers bearing dichlorofluorescein and eosin were obtained in high yield, the related fluorescein bearing monomer could only be obtained in low yield. In the latter case, concurring etherification and esterification led to a product mixture of the desired carboxy modified monomer and a double substituted by‐product. The dye‐monomers were used successfully for the preparation of statistical copolymers with endo,exo‐2,3‐norbornene dicarboxylic acid dimethylester by ROMP. Absorption and luminescence characteristics and, in particular, the acid/base sensitive behavior of the parent dyes were preserved in the monomers and copolymers. The absorption and emission maxima in THF solution and in the solid state were red shifted in comparison to the aqueous samples of the parent dyes. Dye‐copolymers exhibited good film forming properties. Solid state luminescence studies of the copolymers revealed an increasing sensitivity towards NEt3 vapor in the order fluorescein < dichlorofluorescein < eosin bearing copolymer. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1336–1348, 2007 相似文献
757.
758.
Gregor Dolinar Shuanping Du Jinchuan Hou Peter Legia 《Linear algebra and its applications》2008,429(1):100-109
Let be the space of all bounded linear operators on a Banach space X and let LatA be the lattice of invariant subspaces of the operator . We characterize some maps with one of the following preserving properties: Lat(Φ(A)+Φ(B))=Lat(A+B), or Lat(Φ(A)Φ(B))=Lat(AB), or Lat(Φ(A)Φ(B)+Φ(B)Φ(A))=Lat(AB+BA), or Lat(Φ(A)Φ(B)Φ(A))=Lat(ABA), or Lat([Φ(A),Φ(B)])=Lat([A,B]). 相似文献
759.
760.
Total electron yields for perpendicular impact of C+ ions on W have been measured for projectile energies from 0.2 keV to 7 keV. The data are compared with the data of C+ bombardment of gold and graphite in order to demonstrate general trends in kinetic electron yields at low projectile velocities. The total electron yields in the studied combinations of projectiles and substrates show a similar exponential dependence Γ ∝ (v/A) exp(−A/v), where A is a constant and v is the projectile velocity. 相似文献