BINAP/1,4-diamine-ruthenium(II) complexes for efficient asymmetric hydrogenation of 1-tetralones and analogues

A combined system of a RuCl(2)(binap)(1,4-diamine) complex and t-C(4)H(9)OK in i-C(3)H(7)OH catalyzes enantioselective hydrogenation of various 1-tetralone derivatives and some methylated 2-cyclohexenones. Hydrogenation of 2-methyl-1-tetralone under dynamic kinetic resolution gives the cis alcohol with high ee. [reaction: see text]     

Highly self-organized electron transfer from an iridium complex to p-benzoquinone due to formation of a pi-dimer radical anion complex triply bridged by scandium ions

Unusually high kinetic order was observed in self-organized Sc3+-promoted electron transfer from tris(2-phenylpyridine)iridium(III) [Ir(ppy)3] to p-benzoquinone (Q) in propionitrile, third-order with respect to the concentration of Sc3+ and second-order with respect to the concentration of Q, to produce a pi-dimer semiquinone radical anion complex that is triply bridged by three Sc3+ ions (Q*--3Sc3+-Q).     

Nucleophilic acylation of arylfluorides catalyzed by imidazolidenyl carbene

Imidazolidenyl carbene catalyzes nucleophilic acylation reaction of arylfluorides with electron withdrawing groups to give benzophenone derivatives.     

Remarkable effects of counter ions on scandium ion-promoted electron transfer reactions

Scandium ion-promoted electron transfer reactions of p-benzoquinone are remarkably accelerated when tetrakis(pentafluorophenyl)borate anion is used instead of trifluoromethanesulfonate anion as the counter anion of scandium ion. Only a catalytic amount of scandium borate salt (Sc[B(C6F5)4]3) accelerates significantly the Diels-Alder reaction of 9,10-dimethylanthracene with p-benzoquinone, which proceeds via Sc(3+)-promoted electron transfer from the anthracene to p-benzoquinone.     

Enhanced radical-scavenging activity of naturally-oriented artepillin C derivatives

More than two-fold augmentation in the radical-scavenging activity of artepillin C could be achieved via altering the O-H bond dissociation enthalpy of artepillin C by means of structural modifications.     

Capturing of acidic macromolecules from biological samples using a temperature-responsive polymer modified with poly-l-lysine

We synthesized a temperature-responsive polymer, N-(isopropylacrylamide)-methacrylic acid copolymer, to which poly-l-lysine was introduced. The synthesized polymer as well as the parent polymer showed reversible soluble-insoluble changes in response to temperature changes across the lower critical solution temperature at 32 degree C in an aqueous solution. We found that the polymer efficiently captured acidic bio-macromolecules such as RNA, glycosaminoglycans and mucin-type glycoproteins in biological samples, and the captured molecules were recovered using aqueous NaCl solutions at high concentration. The target acidic molecules thus obtained will be employed for further studies such as structural analysis after brief desalting procedure. The proposed method does not require any chromatographic separations, but only needs a small volume of an aqueous salt solution for releasing captured molecules. Overall procedures are quite easy and simple, and are completed at least within 1 h. We show a few examples for capturing RNA and glycosaminoglycans from cultured cells using the polymer.     

Kinetische Untersuchung der Polymerisation von ?thylen mit Al/TiCl4-Katalysator

Ohne Zusammenfassung     

Five new alleles of plasma Zn-alpha 2-glycoprotein variants phenotyped by isoelectric focusing and immunoblotting in twelve populations.

Human Zn-alpha 2-glycoprotein (ZAG) in plasma samples from twelve populations was tested by immunoblotting after polyacrylamide gel isoelectric focusing. Eleven ZAG phenotypes produced by one common and nine rare alleles, including five new ones (ZAG*6-ZAG*10), were detected. Additionally, an application of separator IEF with N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) was found to be useful for discriminating the rare ZAG 7 band.     

Pyrolysis of azidopyrazines

2,3-Dichloro- and 2,5-dichloropyrazines were treated with sodium azide. The former gave diazidopyrazines and the latter, monoazidomonochloropyrazines. Pyrolysis of 2,3-diazidopyrazines resulted the production of 1,2-dicyanoiminoethanes and that of 2-azido-5-chloropyrazines, chloroimidazoles.