Stereoselektive Synthese einiger Amidester der (±)-erythro-2,3-Diphenylglutarsäure

Zusammenfassung Bei der Umsetzung von Methylphenylacetat mit Dialkylamiden der Zimtsäure in Gegenwart von NaNH₂ wurden Amidester der (±)-erythro-2,3-Diphenylglutarsäure hergestellt. Die Konfiguration der erhaltenen Verbindungen wurde durch Hydrolyse mit HCl (1:1) zu der entsprechenden Säure und im Falle der Umsetzung mit dem Zimtsäuredimethylamid durch eine mehrstufige Synthese aus demerythro-Säurenitril-ester festgestellt. Es wurden auch Bedingungen gefunden, unter welchen nur die Estergruppe hydrolysiert werden kann, wobei Mono-dimethylamid entsteht, das mit CH₂N₂ den Ausgangs-Amidester liefert.     

Instrumental neutron activation analysis of brewer's yeast

Instrumental neutron activation was used for the determination of 23 trace and minor elements in 4 different samples of brewer's yeast. Detection limits for these elements vary from 2 ppb to 100 ppm. The following average concentrations were found (ppm, dry weight): Al 597, Br 0.36, Cl 1473, Co 0.21, Cu 19, Fe 285, K 16 400, Mg 1355, Mn 8.4, Na 2330, Rb 19, Sb 0.053, Se 1.2, V 2.2 and Zn 80. NBS standard 1569 was also analyzed and the following concentrations (in ppm) were measured: Al 2300, Br 0.65, Ce 0.23, Cl 460, Co 0.26, Cr 2.12, Cu 11, Fe 707, Gd 7.1, Hf 0.13, K 15 500, Mg 1780, Mn 7, Na 510, Rb 16, Sb 0.075, Sc 0.18, Se 0.92, Th 3.7, Ti 38, U 0.49, V 4.1 and Zn 70.     

Die Synthese von Hydrazinium(+2)-fluoromagnesat

Zusammenfassung Die Reaktion zwischen MgCO₃ und wässerigen Lösungen von Hydraziniumdifluorid und Flußsäure führt zum Hydraziniumfluoromagnesat. Diese Verbindung ist auch aus Magnesiumchlorid-und Hydraziniumdifluorid-Lösungen herstellbar. Es werden röntgenographische, IR-spektrographische und thermogravimetrische Untersuchungen dieser Verbindung angegeben.

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Hydrazinium(+2) fluoromagnesate is formed in the reaction between MgCO₃ and hydrazinium difluoride dissolved in hydrogen fluoride. The reaction of magnesium chloride and an aqueous solution of hydrazinium difluoride yields the same product. The results of X-ray diffraction studies, IR spectroscopical studies and thermogravimetrical investigation are given.

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Mit 3 Abbildungen     

Comparison of nondestructive proton and neutron activation: The case of biological samples

The capabilities of reactor neutron and 12 MeV proton activation were evaluted on samples of orchard leaves, beef liver and bovine liver. Based on γ-ray spectrometry, As, Ca, Cu, Fe, Mo, Pb, Sr, Ti, Zn and Zr at levels ranging from 2 to 20 900 ppm were detected following proton activation of 1 hour. Al, Br, Ca, Cl, Cu, Mg, Mn, Rb and V (ranging from 0.4 to 20 900 ppm) were measured by neutron activation (1 min irradiation). As, Ba, Br, Cr, Co, Fe, Hg, La, Na, Rb, Sb and Zn (ranging from 0.2 to 2400 ppm) were determined following a 14 h neutron irradiation. Although covering different elements, the two techniques are comparable in their scope, i. e. detection limits that can be achieved and number of elements that can be detected simultaneously.     

P, p, T Surfaces of real gases and the Riemann-Hugoniot catastrophe

Analysing experimentally determined P, ?, T data of N₂, ethylene, propene, CO₂ and Xe by a new mathematical technique, we present evidence that their isothermal pressure-density dependence exhibits behaviour characteristic of a Riemann-Hugoniot catastrophe, in analogy to a van der Waals gas for above and sub critical isotherms.     

Syntheses of Novel Isopenam and Isocephem Antibiotics. Preparation of a retinamido derivative of a highly strained β-lactam as potent anticancer agent

Syntheses of the cis-configurated isopenam 9 (Scheme 1), isocephem 14 (Scheme 2), and isocephem 19 (Scheme 3) are described. The key step in the preparation of 14 and 19 involved a Pummerer-type rearrangement of the corresponding sulfoxides 12 and 18 . These β-lactams were found to possess biological activity against several pathogenic microorganisms in vitro. The electronic activation of the lactam moiety of 19 remarkably enhanced its biological activity. A retinoic moiety was attached to 19 via an amino linker. The resultant retinamido-β-lactam 21 showed significant cytostatic activity in tracheal organ cultures obtained from vitamin-A-deficient hamsters.     

Einige analytische Eigenschaften von 1,3-Dimethyl-4,5-diaminouracil

Zusammenfassung 1,3-Dimethyl-4,5-diaminouracil (DAL) hat sich als sehr empfindliches Reagens zum selektiven Nachweis von Co²⁺-Ionen im stark alkalischen Medium einer Phosphatpufferlösung (p_H=11,20) erwiesen. Es wurden vier Additionsverbindungen von DAL mit den Zentralatomen Cd(II), Pd(II), Ni(II) und Co(II) im Verhältnis Me DAL=1 2 hergestellt. Spektrophotometrische Untersuchungen weisen darauf hin, daß bei p_H 6 bis 7 eine Komplexverbindung im Verhältnis CoDAL=12 gebildet wird.

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Summary 1,3-dimethyl-4,5-diaminouracil (DAL) has been found to be a very sensitive reagent for the selective detection of Co²⁺ ions in strong alkaline medium of a phosphate buffer solution (p_H=11.20). Four addition compounds of DAL with the central atoms Cd(II), Pd(II), Ni(II) and Co(II) with the ratio MeDal=12 have been prepared. Spectrophotometric studies indicate that at p_H=6–7, complex compound is produced with the ratio CoDAL=12.

     

Nuclear core in hypernuclear structure

Hypernuclear structure models are briefly reviewed. Phenomena related to hypernuclear polarization are displayed. A discussion is given of nuclear and hypernuclear neutron orbitals extraction. Preliminary results on ^– angular distributions for the reaction⁶Li(K ^–, ^–) ⁶ Li are presented.Presented at the symposium Mesons and Light Nuclei, Liblice, Czechoslovakia, June 1981.The collaboration of Dr. M. Sotona and Dr. L. Majling in the speedy preparation of the AD results and discussions with them and with Prof. B. Povh are greatly acknowledged.     

Absorption properties of körbl-catalyst and manganese dioxide

Summary Körbl-catalyst and manganese dioxide absorb chlorine and bromine quantitatively at room temperature. This property is applied to simultaneous microanalytical determination of carbon, hydrogen and chlorine or bromine in compounds containing carbon, hydrogen, oxygen, chlorine or bromine, but not nitrogen or sulphur.

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Zusammenfassung Der Körbl-Katalysator und Mangandioxid absorbieren Chlor und Brom bei Raumtemperatur quantitativ. Sie wurden daher zur gleichzeitigen Bestimmung von C, H sowie Cl oder Br in Verbindungen verwendet, die C, H, O, Cl (oder Br), nicht aber N oder S enthalten.