14 research outputs found

    Pd-Catalyzed Three-Component Reaction of 3‑(Pinacolatoboryl)ally Acetates, Aldehydes, and Organoboranes: A New Entry to Stereoselective Synthesis of (<i>Z</i>)-<i>anti</i>-Homoallylic Alcohols

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    The Pd-catalyzed three-component reaction of 3-(pinacolato­boryl)­allyl acetates, aldehydes, and organoboranes is described. The reaction is initiated by the formation of an allylic <i>gem</i>-palladium/boryl intermediate, which then undergoes allylation of aldehydes by allylboronates followed by a coupling reaction of in situ generated (<i>Z</i>)-vinylpalladium acetates with organoboranes to provide the (<i>Z</i>)-<i>anti</i>-homoallylic alcohols with high levels of diastereoselectivity and alkene stereocontrol

    Migration behavior of gaseous ruthenium tetroxide under boiling and drying accident condition in reprocessing plant

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    <p>In the boiling and drying accident of high-level liquid waste in the fuel reprocessing plant, behavior of ruthenium (Ru) has attracted much attention because Ru could form volatile compounds such as ruthenium tetroxide (RuO<sub>4</sub>) and could be released into the environment. To contribute towards safety evaluation of this accident, the migration behavior and the leak path factor of the gaseous ruthenium compound has been experimentally measured in this study. The experiment was proceeded by using the ‘Ruthenium Migration Evaluating Apparatus,’ which partially simulates the atmospheric condition (temperature, flow rate, and composition of water vapor and gaseous nitric acid mixture) of migration pathway in the accident. Experiments with dry air and water vapor were also performed as the control experiment to discuss the effect of nitric acid. As a result, the experiment with dry air and the experiment with water vapor demonstrated that the majority of the ruthenium deposited along the migration pathway. On the other hand, the experiment with the water vapor containing gaseous nitric acid demonstrated that almost all of the ruthenium passed through the migration pathway without deposition. These results suggested that the migration behavior of gaseous ruthenium will be affected by the gas-phase composition.</p

    Controllable Stereoselective Synthesis of (<i>Z</i>)<i>-</i> and (<i>E</i>)‑Homoallylic Alcohols Using a Palladium-Catalyzed Three-Component Reaction

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    Diastereoselective synthesis of (<i>Z</i>)- and (<i>E</i>)-homoallylic alcohols using a Pd-catalyzed three-component reaction of 3-(pinacolatoboryl)­allyl benzoates, aldehydes, and aryl stannanes was developed, which provides an alternative method for the allylboration of aldehydes using α,γ-diaryl-substituted allylboronates. Both sets of reaction conditions enable access to either (<i>Z</i>)- or (<i>E</i>)-homoallylic alcohols with good to high alkene stereocontrol. The present method showed good functional group compatibility and generality. Efficient chirality transfer reactions to afford enantioenriched (<i>Z</i>)- and (<i>E</i>)-homoallylic alcohols were also achieved

    Practical and Convenient Synthesis of 1,6-Di- or 1,2,5,6-Tetra-arylhexa-1,3,5-trienes by the Dimerization of Pd(0)-Complexed Alkenylcarbenes Generated from π‑Allylpalladium Intermediates

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    Pd­(0)-complexed 3-aryl or 2,3-diaryl propenylcarbenes generated from α-silyl-, α-germyl-, or α-boryl-σ-allylpalladium intermediates undergo self-dimerization to provide 1,6-di- or 1,2,5,6-tetraarylhexa-1,3,5-trienes in good to high yields. This method allows the use of a π-allylpalladium intermediate for a carbenoid precursor. Furthermore, the obtained 1,2,5,6-tetraarylhexa-1,3,5-trienes exhibit aggregation-induced emission enhancement property

    Method for measuring laser spots.

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    <p>(a) Enlarged photograph of anti-rhodopsin staining at the normal site of retina. (b) Spot created by laser application. (c) The dropout area of anti-rhodopsin staining was measured and calculated as the area of the laser spot.</p

    Schematic representation of laser pattern and the extent of tissue damage according to optical coherence tomography.

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    <p>(a) Color fundus photograph of laser application using PASCAL (Streamline 577™ (Topcon Medical Laser Systems, Inc., Santa Clara, CA, USA) with Endpoint Management (EM) using a 2×3 square pattern and single shot using the PASCAL short-duration method (PSS-SDM) imaged immediately after laser treatment. (b) Schematic representation of the laser pattern in the retina. The laser application settings were fixed at 200 μm (spot size), 20 ms, and a wavelength of 577 μm. Numbers 1 to 6 represent laser spots using EM (2×3 square pattern), while 7 to 14 represent laser spots created by PSS-SDM. (c) Optical coherence tomography immediately after laser application was performed with slices containing laser spots, and the extent of tissue damage at the spot lesion were identified. Percentages indicate the energy setting at each lesion.</p

    Panoramic photograph of fluorescent images of each laser spot.

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    <p>Panoramic photograph of fluorescent images obtained using confocal laser microscopy (original magnification ×60) after immunostaining of extension specimens with mouse anti-rhodopsin, and showing each laser spot. The percentages and mW indicates the energy setting of each method.</p

    Gritty Surface Sample Holder Invented To Obtain Correct X‑ray Absorption Fine Structure Spectra for Concentrated Materials by Fluorescence Yield

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    A gritty surface sample holder has been invented to obtain correct XAFS spectra for concentrated samples by fluorescence yield (FY). Materials are usually mixed with boron nitride (BN) to prepare proper concentrations to measure XAFS spectra. Some materials, however, could not be mixed with BN and would be measured in too concentrated conditions to obtain correct XAFS spectra. Consequently, XAFS spectra will be incorrect typically with decreased intensities of the peaks. We have invented the gritty surface sample holders to obtain correct XAFS spectra even for concentrated materials for FY measurements. Pure Cu and CuO powders were measured mounted on the sample holders, and the same spectra were obtained as transmission spectra of properly prepared samples. This sample holder is useful to measure XAFS for any concentrated materials

    Comparison of grades in three different types of laser methods.

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    <p>Using Endpoint Management (EM), the laser spots were visible at 100% to 20%, and invisible at 10%. The tissue effects were identifiable at 20%; however, tissue damage was not apparent in 10% and appeared as normal structure. The extent of tissue damage in the outer nuclear layer at 30%, in inner segment/outer segment at 20% were detected by optical coherence tomography (OCT), and structural irregularity in outer nuclear layer (ONL) was identified at 20%, whereas 10% had normal structure according to three-dimensional histopathological imaging.</p
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