Generation of 2-Carboethoxyethylzinc iodide and 3-carboethoxypropylzinc iodide and their application to the synthesis of γ- and δ-keto esters

2-Carboethoxyethylzinc iodide and 3-carboethoxypropylzinc iodide are generated by the reaction of the corresponding iodoesters with Zn-Cu couple and utilized for the palladium catalyzed coupling reaction with acid chloride to quantitatively provide gamma- and delta- keto esters, respectively.     

Thermal decomposition of propyne and allene in shock waves

Propyne (p-C₃H₄) or allene (a-C₃H₄) mixtures, highly diluted with Ar, were heated to the temperature range 1200–1570 K at pressures of 1.7–2.6 atm behind reflected shock waves. The thermal decompositions of propyne and allene were studied by both measuring the profiles of the IR emission at 3.48 μm or 5.18 μm and analyzing the concentrations of reacted gas mixtures. The mechanism and the rate constant expressions were discussed from both the profiles and the concentrations of reactant and products obtained. The rate constant expressions for reactions, (1) p-C₃H₄ → a-C₃H₄, (?1) a-C₃H₄ → p-C₃H₄, and (5) p-C₃H₄ + H → CH₃ + C₂H₂ were evaluated.     

The correlation between molecular weight and antitumor activity of galactosaminoglycan (CO-N) from Cordyceps ophioglossoides

A galactosaminoglycan (CO-N) obtained by ultrasonication from a protein-bound polysaccharide SN-C, which was isolated from Cordyceps ophioglossoides culture, has a direct cytotoxicity against tumor cells (Ohmori et al., Chem. Pharm. Bull., 37, 1019 (1989). High performance liquid chromatographic analysis revealed that CO-N shows a broad molecular weight distribution with an average molecular weight of 33000. A potent antitumor activity of CO-N was observed in the higher-molecular-weight fraction on gel filtration, and the low-molecular-weight fraction below 6600 showed a weak activity. However, the depolymerized CO-N (ca. 5500) obtained by further ultrasonication of the original CO-N still retained the antitumor activity of CO-N against Ehrlich ascitic carcinoma or MM46 solid mammary carcinoma.     

Rotational isomerism inbis carbene MOL4 complexes: A theoretical study

LCAO-MO-SCF calculations are reported for the different stereoisomers of the Mo(CO)₄(CH₂)₂ and Mo(CO)₄[C(NH₂)₂]₂ systems. The substitution of the hydrogen atoms by the amino groups in the carbene ligands leads to an almost zero rotational barrier. Steric interactions are therefore expected to govern the barrier for diaminocarbene ligands which are more bulky than C(NH₂)₂. The rotational isomerism in thesebis carbene MoL₄ systems is also discussed in connection with the isolobal analogy between CH₂ and C₂H₄.     

Selective preconcentration of copper from aqueous solution by using kerateine gel

Summary A selective preconcentration technique for copper using the kerateine gel is described. The gel is prepared by partial oxidation of kerateine which is obtained by reducing the disulphide bonds of wool fiber. Copper is selectively adsorbed on the gel at pH 3.5. It is eluted with 3 M hydrochloric acid and is determined by atomic-absorption spectrometry. This method has been applied to the determination of copper in river water.

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Selektive Anreicherung von Kupfer aus wäßriger Lösung mit Hilfe von Keratein-Gel

Zusammenfassung Ein selektives Anreicherungsverfahren für Kupfer mit Hilfe von Keratein-Gel wurde ausgearbeitet. Das Gel wird durch teilweise Oxidation von Keratein hergestellt, das aus Wollfaser durch Reduktion der Disulfidbindungen gewonnen wird. Kupfer wird bei pH 3,5 selektiv an diesem Gel adsorbiert und kann mit 3 M Salzsäure eluiert werden. Die Bestimmung erfolgt mit Hilfe der AAS. Das Verfahren kann zur Kupferbestimmung in Flußwasser angewendet werden.

     

Species and organ differences of sulphate conjugation of p-nitrophenol in liver and platelets.

Sulphate conjugation of p-nitrophenol (p-NP) in the liver and platelet cytosol of guinea pigs, rabbits and dogs were studied. The dependency of phenol sulphotransferase (PST) activity on p-NP concentration in the liver of guinea pigs and rabbits and in the platelets of guinea pigs were similar to that reported for the liver (Mizuma et al., J. Pharmacobio-Dyn., 6, 851 (1983)) and platelets (Nakamura et al., J. Pharm. Pharmacol., 42, 207 (1990)) of rats. There was one peak of PST activity on p-NP at the concentration of 1 to 10 microM, and the PST activity was increased again with an increase of p-NP concentration above the original concentration. On the other hand, a peak in PST activity on p-NP at the concentration of 1 to 10 microM was not observed in the platelets of rabbits and dogs. These results indicated species and organ differences in PST activity on p-NP in liver and platelets. The biphasic activities of the PST and p-NP in platelets and liver of rat and guinea pig were similar to that reported in humans (Reiter et al., Naunyn-Schmiedeberg's Arch. Pharmacol., 324, 140 (1983)).     

Magnetic order in La2-x Bax CuO4 and La1.6-x Nd0.4 Srx CuO4 for x=0.125

We present μSR experiments on La_2-x Ba_x CuO₄ and La_1.6-x Nd_0.4 Sr_x CuO₄ for x=0.125. Both of these materials order magnetically with T_N\approx30\ K, while a superconducting sample of La_1.4 Nd_0.4 Sr_0.2 CuO₄ showed no evidence for static copper moments. Our results support the conclusion that the so‐called “1/8” anomaly in La_2-x Ba_x CuO₄ is a result of static (pinned) charge segregation. This revised version was published online in August 2006 with corrections to the Cover Date.     

Role of electron spin in integer quantum hall photoluminescence

We investigate numerically the photoluminescence (PL) spectrum in the integer quantum Hall regime and find that the electron spins play important roles. The spectra for the left circularly polarized light show peak splittings when the Fermi levels lies in the excited Landau level, which is caused by the inter Landau level scattering between electrons with anti-parallel spins. At around ν_e∼1 the PL energy is strongly affected by the interplay between the screening and multiple spin flipping (skyrmion) effects.     

β-delayed neutron decay of drip line nuclei 11Li and 14Be

Experimental studies of β-decay measurements of the neutron drip line nuclei ¹¹Li and ¹⁴Be are presented. β- decay schemes of these nuclei are determined by measuring β-rays, delayed neutrons and γ-rays in triple coincidence. The decay schemes of both ¹¹Li and ¹⁴Be associated with single neutron emission are unambiguously determined. New levels in their daughter nuclei, ¹¹Be and ¹⁴B, are found. In addition, the deduced level scheme of 14B indicates the lowering of 2s _1/2 single neutron orbital with respect to 1p _1/2 orbital in the N=9 isotones. Such behavior is known to exist in N=7.