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101.
Zusammenfassung Es wird über die Synthese und Racematspaltung von drei Benzol-chromtricarbonyl-derivaten sowie der -Methyl-ferrocen-carbonsäure berichtet. Die Absolutkonfiguration von (+)-(1-Tetralon)-Cr(CO)3 konnte als (1S) ermittelt werden. Bei den beiden isomeren Säuren (+)- bzw. (–)-(o- bzw. m-Tolylsäure)-Cr(CO)3 gelang erstmalig die konfigurative Korrelation eines -mit einem -disubstituierten Metallocen. Die Absolutkonfiguration des auch durch asymmetrische Synthese zugänglichen (+)-(o-Tolylsäure)-Cr(CO)3 ließ sich auf Grund der Ergebnisse der kinetischen Racematspaltung der Anhydride der beiden racem. -Methyl-metallocen-carbonsäuren mit (–)-Menthol und (–)--Phenäthylamin als (1
S) bestimmen, da die Konfiguration der Methyl-ferrocencarbonsäure (nach chemischer Korrelation) bekannt war.
Mit 1 Abbildung
7. Mitt.:H. Falk undK. Schlögl, Tetrahedron [London], im Druck. 相似文献
The synthesis and optical resolution of three benzene chromium tricarbonyl derivatives and of -methyl ferrocene carboxylic acid are reported. The absolute configuration of (+)-1-tetralone)-Cr(CO)3 was established as (1S). In the case of the isomeric acids (+)-(o-toluic acid)- and (–)-(m-toluic acid)-Cr(CO)3 resp. a configurational correlation of - and -disubstituted metallocenes was possible for the first time. The absolute configuration of (+)-(o-toluic acid)-Cr(CO)3 (which is also accessible by asymmetric synthesis) could be established as (1S) by kinetic resolutions of the anhydrides of the two racemic -methyl metallocene carboxylic acids with (–)-menthol and (–)--phenethylamine, since (after chemical correlation) the configuration of methyl ferrocene carboxylic acid was known.
Mit 1 Abbildung
7. Mitt.:H. Falk undK. Schlögl, Tetrahedron [London], im Druck. 相似文献
102.
Hubert A Popp P Wenzel KD Engewald W Schüürmann G 《Analytical and bioanalytical chemistry》2003,376(1):53-60
A new one-step cleanup procedure, based on size-exclusion chromatography (SEC), usable for the extracts from accelerated solvent extraction (ASE), Soxhlet extraction, or ultrasonic extraction (USE), is described. The method is suitable for the determination of polycyclic aromatic hydrocarbons (PAHs), especially from very complicated plant matrices (e.g. pine needles, deciduous leaves, mosses). The main improvement compared with previous conventional procedures is that analyte peaks barely overlap with matrix peaks in the chromatograms and that it is a very rapid and simple one-step procedure with clearly improved analytical performance. Essential advantages of this SEC procedure are the sharper GC-MS chromatograms for the PAH fraction at retention times between 9.2 and 12.0 min, distinctly separated substance peaks resulting in better analysis, shorter running times, and lower solvent consumption. 相似文献
103.
Separation of the enzymes formate dehydrogenase, formaldehyde dehydrogenase and methanol oxidase from Candida boidinii crude extract has been explored using continuous flow zone electrophoresis in the VaP-22 and the scaled-up VaP-220 electrophoresis apparatus. Yields up to 95% and purification factors between 3 and 7 were obtained, together with separation of cell debris from the enzymes. Multiple injections of sample were used to obtain a protein throughput of 46.2 mg/h in the VaP-22. A tenfold higher throughput was achieved using the VaP-220. Correlation of the electrophoretic mobility in continuous flow zone electrophoresis with the elution behavior in ion-exchange chromatography confirmed the primary role of net surface charge in the separation of biological molecules. Proteins and enzymes with differences greater than 0.05 M elution molarities in ion-exchange chromatography can be separated. This corresponds to a preparative scale (mg/h or g/h) separation of proteins and enzymes whose difference in apparent electrophoretic mobility is greater than 0.70 x 10(-5) cm2/(V.s). 相似文献
104.
Zusammenfassung Bei der Einwirkung von elementarem Schwefel auf Phenacyl-sulfenylmorpholid entsteht unter H2S-Abspaltung Phenylglyoxyl-säurethionmorpholid. Durch Einsatz von radioaktivem Schwefel wurde festgestellt, daß diese Umlagerungsreaktion über die Stufe einergem. Dimercaptoverbindung verläuft.
47. Mitt.:F. Asinger, W. Schäfer undA. Saus, Mh. Chem.96, 1265 (1965).
Teil der DissertationA. Saus, Techn. Hochsch. Aachen, 1964. 相似文献
Reaction of elementary sulfur with phenacylsulfenylmorpholide gives phenylglyoxylic acid thionmorpholide while hydrogen sulfide is eliminated. The rearrangement proceeds, as was shown by use of radioactive sulfur, via agem. dimercaptocompound as intermediate.
47. Mitt.:F. Asinger, W. Schäfer undA. Saus, Mh. Chem.96, 1265 (1965).
Teil der DissertationA. Saus, Techn. Hochsch. Aachen, 1964. 相似文献
105.
Zusammenfassung Die Aufnahme von Nitrilotriessigsäure-Komplexen von Strontium, Blei, Yttrium, Wismut und Thorium durch den Anionenaustauscher Dowex-1 wurde untersucht, indem die Elutionsgeschwindigkeiten radioaktiver Isotope dieser Elemente aus Austauschersäulen gemessen wurden. Für die Versuche wurde mit Nitrilotriacetat (NTA) beladener Austauscher verwendet; als Elutionsmittel dienten NTA-Lösungen verschiedener Konzentration. Die ermittelten Verteilungskoeffizienten (Austauscher/Lösung) geben Hinweise auf die Ladungszahlen der für die Aufnahme in den Austauscher maßgeblichen Metall-NTA-Komplexe und damit auf deren Zusammensetzung. Sie liefern auch Aussagen über die Wechselwirkung zwischen den komplexen Anionen und dem Austauscher. Anwendungsmöglichkeiten der Aufnahme von NTA-Komplexen in den Anionenaustauscher für radiochemische Trennungen werden aufgezeigt.Mit 3 Abbildungen 相似文献
106.
Heinz Falk Thomas Schlederer Peter Wolschann 《Monatshefte für Chemie / Chemical Monthly》1981,112(2):199-207
The long standing problem of solvent dependent absorption spectra of certain bile pigments such as bilirubindimethylester has been solved by measurement of molecular masses by means of vapour pressure osmometry. Using this method and the investigation of the concentration and temperature dependence of the absorption spectra on several model compounds an association equilibrium for pigments of the rubinoid structural type could be confirmed. Moreover the optical properties of the coexisting species and the corresponding equilibrium constants could be deduced by spectroscopic techniques. Verdinoid pigments lacking free carboxylic functions on the other hand tend to be monomeric in solution. A heteroassociated species involving equimolar amounts of a verdinoid and a rubinoid pigment could be verified existing on adsorbents like silicagel.
37. Mitt.:Falk, H., Thirring, K., Tetrahedron, im Druck. 相似文献
107.
The reaction of fluorenone ethyleneketal (9), diphenic anhydride as well as of biphenyls such as4 with Cr(CO)6 in refluxing di-n-butylether (BE) gives dimethylbenchrotrenes [xylene-Cr(CO)3,7] which are also formed by refluxing pureBE with Cr(CO)6—although with much lower yields. Similarily, from di-n-pentylether and Cr(CO)6 isobutyl- and 1-methyl-3-propyl-benchrotrene (13 and14) were obtained, whilst from di-n-propyl- and-hexylether, resp., and Cr(CO)6 no benchrotrenes could be isolated.Tentative assumptions on the catalytic action of certain functional groups were confirmed by the reaction ofBE and Cr(CO)6 in the presence of carbonamides, such as acetamide, urea and pyrrolidone, where 1,4-dimethylbenchrotrene (7 c) was formed with appreciable yields.Studies using dideuteratedBE showed that—at least for the reaction of9 with Cr(CO)6 (giving a much lower yield of7 than with undeuteratedBE)—a simple bimolecular mechanism can be excluded. 相似文献
108.
Lu AH Li WC Kiefer A Schmidt W Bill E Fink G Schüth F 《Journal of the American Chemical Society》2004,126(28):8616-8617
Magnetically separable mesostructured silica with an unobstructed pore system was fabricated through the deposition of cobalt nanoparticles on the outer surface of the submicron-sized silica particles. These cobalt nanoparticles were further protected by a nanometer-thick carbon shell against acid erosion. Due to the fact that the magnetic particles are grafted on the outer surface of the porous silica, the pores are still accessible for further modification, which could widen the application range of porous silica. 相似文献
109.
Martina Dotzler Astrid Schmidt Jochen Ellermann Falk A. Knoch Matthias Moll Walter Bauer 《Polyhedron》1996,15(24):4425-4433
BiBr3 or SbI3 react at 20°C with LiN(PPh2)2 (1) to give elementary Bi or Sb and the P---P coupled phosphazene ligand Ph2P---N=PPh2---PPh2=N---PPh2 (2). The reaction of AsI3 with 1 at room temperature formed yellow needles of the eight-membered heterocycle
(3), whereas AsI3 interacted at 80°C with 1 in the molar ratio of 1:3 to give elementary arsenic and 2. Treatment of AsI3 and 1 at 20°C in a 1:2 stoichiometry yielded the seven-membered, cyclic arsenium(I) salt I·4THF (5·4THF), which was characterized by elemental analysis, conductivity, mass, IR and NMR spectroscopy and single-crystal X-ray structural analysis. 相似文献
110.