Alkylation of aminohydroxy anion,dissociated species of hydroxylamine

Aminohydroxy anion ($\text{3}$), dissociated species of hydroxylamine, was demonstrated to be nucleophilic on oxygen atom from INDO calculation, and to give directly O-alkylhydroxylamines.     

Tight quadrangulations on the sphere

A quadrangulation is a simple graph on the sphere each of whose faces is quadrilateral. A quadrangulation G is said to be tight if each edge of G is incident to a vertex of degree exactly 3. We prove that any two tight quadrangulations with n?11 vertices, not isomorphic to pseudo double wheels, can be transformed into each other, through only tight quadrangulations, by at most rhombus rotations. If we restrict quadrangulations to be 3-connected, then the number of rhombus rotations can be decreased to 2n-22.     

Myrmekiosides a and b, novel mono-o-alkyl-diglycosylglycerols reversing tumor cell morphology of ras-transformed cells from a marine sponge of myrmekioderma sp

Novel mono-O-alkyl-diglycosylglycerols named myrmekiosides A (1) and B (2) were isolated from a marine sponge of Myrmekioderma sp. and their absolute stereostructures were elucidated on the basis of chemical and physicochemical evidence. Myrmekiosides A (1) and B (2) reversed the phenotype of melanoma H-ras transformed NIH3T3 cells at 5 μg/ml.     

Retention Behavior of Nucleic Acid Bases and Purine Derivatives on Titania

The retention of nucleic acid bases and purine derivatives on titania was studied using a 0.4 mM acetic acid–sodium acetate buffer (pH 6.0) and 70% aqueous methanol as mobile phases. We observed that the retention strength of tested analytes on titania was dependent on the structural differences between pyrimidine and purine skeletons and the variety and number of substituents. The retention order was purine derivatives with methyl groups, pyrimidine bases and purine derivatives with hydrophilic functional groups, which were retained most strongly on titania. We concluded that the retention of each analyte was caused by the analyte’s hydrophobicity in the case of purine derivatives with methyl groups and pyrimidine bases. In the case of purine and its derivatives with hydrophilic functional groups, it was considered that the retention was dependent on the analyte’s ability to form chelates, and the variety and number of functional groups on C6 and C2.     

The correlation between electrical properties and surface plasmonic properties on ITO films with diffraction grating

Optical Review - The correlation between electrical properties and surface plasmon resonance (SPR) wavelength was discussed using ITO grating coupler. ITO films were prepared on SiO $$_{2}$$ /Si...     

Group 6 metal complexes with a hemilabile tridentate xantsil ligand and facile insertion of tBuCN into a W-Si bond [xantsil = (9,9-dimethylxanthene-4,5-diyl)bis(dimethylsilyl)

The synthesis and characterization of tungsten and molybdenum complexes of the xanthene-based bis(silyl) ligand (xantsil) with a kappa3(Si,Si,O) coordination mode are reported, where an insertion of tBuCN into a tungsten-silicon bond leads to formation of an eta2-iminoacyl complex.     

Stereo-controlled synthesis of analogs of peumusolide A, NES non-antagonistic inhibitor for nuclear export of MEK

Stereo-controlled construction of the core structure of peumusolide A (1), α-alkylidene-β-hydroxy-γ-methylenebutyrolactone, was developed by a combination of regio- and stereo-selective hydroiodination of 2-yn-1-ol and asymmetric reduction of 1-yn-4-en-3-one as the key reactions. By using this protocol, all the four stereoisomers of the analog of 1 were synthesized from the common starting material.     

Solute partition study in aqueous sodium dodecyl sulfate micellar solutions for some organic reagents and metal chelates

The partition constants (K _d) have been estimated for nitrophenols, thiazolylazo dyestuffs and metal chelate compounds into the sodium dodecyl sulfate (SDS) micellar phase at an ionic strength of 0.10M [(H⁺, Na⁺)Cl^–] and at 20 °C. The equilibrium partition data obtained by batch-wise solution spectrophotometry (equilibrium shift method) agree well with those by the micellar electrokinetic capillary chromatography (MECC) with the SDS micellar pseudo-stationary phase. The MECC clearly discriminates a very small difference (0.03) in the logK _d values of some metal chelates. The plot of theK _d values with the van der Waals volume of the solute molecules obviously shows the leveling-off of theK _d values over solute size near 110 ml/mol, which seems to be consistent with the results obtained in the Triton X-100 micellar system. This phenomenon arises most probably from the rigidity of the micellar pseudo-phase (a micellar volume-constraint effect) in sharp contrast with true two-phase partitioning such as solvent extraction systems.     

Flow-through micro sensor using immobilized peroxidase with chemiluminometric FIA system for determining hydrogen peroxide.

A micromachined flow cell (overall size; 25 x 25 x 1 mm3) was designed for the fast determination of hydrogen peroxide, based on a luminol-H2O2 chemiluminescence reaction catalyzed by immobilized peroxidase (POD). The flow cell consisted of a sandwich of anisotropically etched silicon and glass chips and contained a spiral channel (20 turns, 50 cm long, 150 microm wide, 20 microm depth, channel volume 1.4 microl) and two holes (1 mm diameter). POD was covalently immobilized with 3-(trimethoxysilyl)propyldietylenetriamine and glutaraldehyde on the inner surface of the channel. The chip was placed in front of a window of a photomultiplier tube and used as a flow cell in a single-line flow-injection analysis system using a luminol solution as a carrier solution. The sample volume for one measurement was 0.2 microl. The maximal sampling rate was 315 h(-1) at a carrier solution flow rate of 10 microl min(-1). A calibration graph for H2O2 was linear for 5 nM - 5 microM; the detection limit (signal-to-noise = 3) was 1 nM (7 fg in 0.2 microl injection). The H2O2 concentration in rainwater was determined using this sensor system.