Rhodium-catalyzed addition of arylstannanes to carbon-heteroatom double bond

The addition of arylstannanes to the carbon-heteroatom double bond in the presence of a catalytic amount of a cationic rhodium complex ([Rh(cod)(MeCN)₂]BF₄) was examined. The reactions of aldehydes, α-dicarbonyl compounds, and N-substituted aldimines with the arylstannanes gave corresponding alcohols, α-hydroxy carbonyl compounds, and amines, respectively. An arylrhodium complex generated by the transmetalation with the arylstannane was probably the active catalytic species.     

A novel greener glycosidation using an acid-ionic liquid containing a protic acid

The glycosidations of glucopyranosyl diethyl phosphite and alcohols using an ionic liquid, 1-n-hexyl-3-methylimidazolium trifluoromethanesulfonimidide (C₆mim[NTf₂]) containing a protic acid, trifluoromethanesulfonimide (HNTf₂), as a novel solvent-catalyst system, effectively proceeded under mild conditions to give the corresponding glycosides in good to high yields. Furthermore, this acid-ionic liquid combination could be reused many times for the glycosidations without any loss in efficiency.     

Quantitative assessment of solid oxide electrochemical doping

Quantitative analysis of metal cation doping by solid oxide electrochemical doping (SOED) has been performed under galvanostatic doping conditions. A M–β″-Al₂O₃ (M=Ag, Na) microelectrode (contact radius: about 10 μm) was used as cation source to attain a homogeneous solid–solid contact between the β″-Al₂O₃ and doping target. In Ag doping into alkali borate glass, the measured dopant amount closely matched the theoretical value. High Faraday efficiencies of above 90% were obtained. This suggests that the dopant amount can be precisely controlled on a micromole scale by the electric charge during electrolysis. On the other hand, current efficiencies of Na doping into Bi₂Sr₂CaCu₂O_y (BSCCO) ceramics depended on the applied constant current. Efficiencies of above 80% were achieved at a constant current of 10 μA (1.6 A cm⁻²). The relatively low efficiencies were explained by the saturation of BSCCO grain boundaries with Na. By contrast, excess Na was detected on the anodic surface of ceramics at a constant current of 100 μA (16 A cm⁻²). In the present study, we demonstrate that SOED enables micromole-scale control over dopant amount.     

Polarization Sensitive Spectral Interferometric Optical Coherence Tomography for Biological Samples

A spectral interferometric optical coherence tomography (OCT) system which has polarization sensitivity is developed. This system reduces the mechanical scanning dimension by employing the principle of spectral interferometry, and measures a two dimensional cross-sectional image of biological tissue with one dimensional mechanical scanning. Sixteen OCT images with different polarization conditions are measured, and two dimensional distributions of each element of the Müller matrix of a sample to be measured are calculated.     

Simultaneous catalytic removal of NOϰ and diesel soot particulates

The simultaneous removal of NO_? and soot particulates in an oxidizing atmosphere is desirable for the aftertreatment of diesel exhausts. After briefly reviewing the development of catalysts for reactions involving carbons, our recent studies on the simultaneous NO_?–soot removal using perovskite-related and spinel-type oxides are described.     

The mechanism of photocatalytic hydrogen production from gaseous methanol and water: IR spectroscopic approach

IR spectroscopic and volumetric study under reaction conditions of the mechanism of photocatalytic hydrogen production from gaseous methanol and water revealed that CO₂ and H₂ were produced by reaction between adsorbed CH₃O(ad) and H₂O. Another reaction path for H₂ production, CH₃ OH(ad) → H₂ + HCHO, was suggested which is dominant in the absence of water.     

Inhibitory effects of 3-O-acyl-(+)-catechins on Epstein-Barr virus activation

In the course of an exploratory investigation of antitumor-promoting catechins, 3-O-acyl-(+)-catechins of varying carbon lengths from C(4) to C(18) were assessed for inhibitory effects on the activation of the Epstein-Barr virus early antigen. Like 3-O-acyl-(-)-epigallocatechins, the (+)-catechin derivatives showed promising effects with the C-3 acyl chain of C(8)-C(11) carbon atoms.     

Enantioselective Strecker-type reaction to sulfonylimines having a 2-pyridylsulfonyl group as a novel stereocontroller

A catalytic enantioselective Strecker-type reaction to N-(2-pyridylsulfonyl)imines in the presence of chiral bis(oxazoline)s afforded the products with a high enantioselectivity. A dynamically induced new chiral center on the sulfur by discriminative coordination of a chiral Lewis acid to one of the sulfonyl oxygens efficiently controlled the enantioselectivity.     

Synthesis and thermal decomposition of lanthanide hexacyanochromate(iii) complexes,Ln[Cr(CN)6]·nH2O (Ln=La-Lu; n=3, 4)

New solid complex of nitrilotriacetic acid and bismuth trichloride was synthesized by a solid phase reaction of nitrilotriacetic acid and bismuth trichloride at room temperature. The composition of the sample is BiCl₃[N(CH₂COOH)₃]_2.5. The crystal structure of the complex belongs to triclinic system with the lattice parameters: α=0.7849 nm, β=0.9821 nm, χ=2.0021 nm, α=96.50°, β=98.76° and γ=90.49°. The far-infrared spectra show the bonding between the Bi ion and N atom of nitrilotriacetic acid. The thermal analysis also demonstrates the complex formation between the bismuth ion and nitrilotriacetic acid. The gaseous pyrolysis product and the final residue in the thermal decomposition process are determined to check the thermal decomposition reaction. This revised version was published online in August 2006 with corrections to the Cover Date.     

Purification of a marine bacterial glucose dehydrogenase fromCytophaga marinoflava and its application for measurement of 1,5-anhydro-d-glucitol

A novel glucose dehydrogenase (GDH) from a marine bacteriumCytophaga marinoflava IFO 14170 was isolated from its membrane fraction. This GDH catalyzes the oxidation of a hydroxy group of glucose, but does not react in its C-l position. This enzyme is composed of a single peptide with a mol wt of 67,000. The GDH can react under high salinity. The optimum pH is around 8.0, showing a typical property of marine bacterial enzymes. Using this novel enzyme, an enzymatic determination of 1,5-anhydro-D-glucitol (1,5AG) utilizing 2,6-dichrolophenolindophenol (DCIP) and phenazine methosulfate (PMS) as electron mediators was caried out. A good linear correlation was observed from 0.5 mM to 4 mM of 1,5AG.