Der Stoffwechsel von Verbindungen mit Dreifachbindung. VI. Stoffwechselverhalten von Alkincarbonsäuren und Alkindicarbonsäuren

Metabolism of Acetylenic Monocarboxylic and Dicarboxylic Acids Feeding of acetylenic monoacids with chain length of 11 to 18 C-atoms to rats led to excretion of dicarboxylic acids with retained triple bonds. 10-Octadecynoic acid led to the formation of metabolites with even and odd number of C-atoms, suggesting in addition to established ω- and β-oxidation an α-oxidative pathway.     

Chloracylierung und Bromacylierung von Carbonylverbindungen: Eine in Vergessenheit geratene Carbonylreaktion. I. Präparative Anwendungsbreite

Chloroacylation and bromoacylation of carbonyl compounds: A forgotten carbonyl reaction. I. Scope of the reaction Aliphatic, α,β-unsaturated and aromatic aldehydes as well as aliphatic ketones react with acyl halides to (α-haloalkyl)esters. These bifunctional derivates contain two leaving groups of different reactivity. The scope of this scarcely of this scarcely known carbonyl reaction is discussed.     

121Sb-Mössbauer-Spektren von Antimon(V)-Verbindungen. II

¹²¹Sb Mössbauer Spectra of Antimony (V) Compounds. II The Mössbauer resonance effect of ¹²¹Sb has been studied at 4.2 K in a series of 11 antimony(V) compounds which are in most cases bridged. Isomer shift and quadrupole splitting variations are considered in the light of results of X-ray and vibrational spectroscopy. Preparation and the vibrational spectra of [NMe₄][SbCl₄(n₃)₂] are described. Within the limitations of available structural data related tin compounds are compared with those of corresponding ¹¹⁹Sn Mössbauer spectra.     

Messungen zum lateralen Auflösungsvermögen für Röntgenquanten bei der Elektronenstrahl-Mikroanalyse

Zusammenfassung Die experimentelle Bestimmung der lateralen Ausdehnung des Röntgenemissionsvolumens gelingt aus Intensitätsmessungen an Schichten, deren Dicken in der Größenordnung der lateralen Ausdehnung liegen. Die Schichtsysteme werden dabei mit definierter Geschwindigkeit unter dem Elektronenstrahl hinweg bewegt, was einem Wandern des Röntgenemissionsvolumens durch das Schichtsystem gleichkommt. Von einer Schicht, deren Röntgenintensität gerade das Maximum eines Reinelement-Massivstandards erreicht, kann angenommen werden, daß ihre Dicke der lateralen Ausdehnung entspricht. Zur Messung der Schichtdicken wurden in erster Linie Liniendiagramme herangezogen; die Überprüfung erfolgte aus Röntgenrasterbildern der Elementverteilung.Die geeignete Auswahl der Proben, die aus Schichten leichter (Kohlenstoff), mittlerer (Kupfer) und schwerer (Gold) Elemente bestehen, gestattete die Interpolation der Ergebnisse auf Elemente beliebiger Ordnungszahl. Die Messung der Röntgenintensitäten bei verschiedener Anregungsenergie des Elektronenstrahls ergibt die Abhängigkeit der lateralen Ausdehnung von der Beschleunigungs-spannung.

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Measurements of the lateral resolution of X-ray emission by means of electron microprobe analysis

Summary The experimental determination of the diameter of the X-ray emission volume is obtained from intensity measurements on layers whose thickness lie in the range of this emission volume. The vertically orientated sandwich layers were moved with a definite velocity under the electron probe which amounts to a wandering of the X-ray emission volume through this system of layers. From a layer whose X-ray intensity is equivalent to maximum intensity of a bulk standard of the same material as the layer, one can assume that the diameter of the X-ray emission volume corresponds to the thickness of the layer. To measure the layer thickness, mostly linescans were used, followed by X-ray scan pictures of the element distribution to verify the same.A suitable choice of samples representing light (carbon), medium (copper) and heavy (gold) elements enables to interpolate the results on elements of any other mass number. The measurement of the X-ray intensity under varying electron energies shows the dependance of the diameter of the X-ray emission volume on accelerating voltage.

     

Carbon-carbon bond formation between alkylated alkenes and acrylic ester via 2-methoxyalkyl radicals

Methoxymercuration/demercuration reactions of alkenes 10 in $\text{10}$ in the presence of acrylic ester yield products $\text{11}$ in a carbon-carbon bond formation reaction.