42 research outputs found

    Toward Design of Ag(I) and Au(I) Complexes with Planar Tetracoordinate Carbon Using Novel Ligands

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    We have designed a family of novel molecules that can act as a donor at a carbon atom to coordinate with Ag­(I) and Au­(I) to achieve stable complexes with a planar tetracoordinate carbon (ptC). Then, a kind of new strategy for the design of the compound with a ptC was provided

    Olefination of Electron-Deficient Alkenes with Allyl Acetate: Stereo- and Regioselective Access to (2<i>Z</i>,4<i>E</i>)‑Dienamides

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    A Ru-catalyzed direct olefination of electron-deficient alkenes with allyl acetate via C–H bond activation is disclosed. By using <i>N</i>,<i>N</i>-disubstituted aminocarbonyl as the directing group, this external oxidant-free protocol resulted in high reaction efficiency and good stereo- and regioselectivities, which opens a novel synthetic passway for access to (<i>Z</i>,<i>E</i>)-butadiene skeletons

    DNA-Conjugated Cyclopropane Derivatives Constructed from Sulfonium Ylides with <i>α,β</i>-Unsaturated Ketones

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    Here, we report a DNA-compatible reaction for the generation of cyclopropane derivatives using thiolides with α,β-unsaturated ketones in the absence of transition metal and N2 protection, which is convenient for DNA encoded library (DEL) construction. This approach allows the rapid and efficient production of a series of DEL libraries of potentially biologically active cyclopropanes and spirocyclopropyl oxindole derivatives

    Legislative Documents

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    Also, variously referred to as: House bills; House documents; House legislative documents; legislative documents; General Court documents

    Amide Directed Cross-Coupling between Alkenes and Alkynes: A Regio- and Stereoselective Approach to Substituted (2<i>Z</i>,4<i>Z</i>)‑Dienamides

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    A ruthenium-catalyzed direct cross-coupling between alkenes and alkynes via directed C–H bond activation is described. By using <i>N</i>,<i>N</i>-disubstituted aminocarbonyl as a directing group, this oxidant-free and atom-economic protocol resulted in high efficiency and good stereoselectivities, which opens a novel synthetic passway for access to substituted (<i>Z</i>,<i>Z</i>)-butadiene skeletons

    Susceptibility of Overweight Mice to Liver Injury as a Result of the ZnO Nanoparticle-Enhanced Liver Deposition of Pb<sup>2+</sup>

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    The prevalence of the applications of nanomaterials in consumer products and water treatment facilities increases the chance that humans will be exposed to both nanoparticles and environmental pollutants such as heavy metals. Co-exposure to nanoparticles and heavy metals may adversely affect human health, especially in susceptible populations such as overweight subjects. To evaluate the impact of such co-exposures, we orally administered zinc oxide nanoparticles (ZNPs; 14 or 58 nm) and/or Pb­(Ac)<sub>2</sub> at tolerable doses to both healthy overweight and healthy normal weight mice. The ZNPs enhanced the deposition of Pb in all major organs in the overweight mice compared with that in the normal mice. As a result, higher levels of hepatic reactive oxygen species, pro-inflammatory cytokines, and liver injury were observed in the overweight mice but not in the normal weight mice. Our findings underscore a potentially enhanced risk of nanoparticle/heavy metal co-exposure in the susceptible overweight population

    Transition-Metal-Free N–O Reduction of Oximes: A Modular Synthesis of Fluorinated Pyridines

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    An NH<sub>4</sub>I-based reductive system has been explored to promote the oxime N–O bond cleavage and thereby enable a modular synthesis of a broad range of pharmacologically significant fluorinated pyridines. Compared with traditional condensation methods for pyridine assembly, this protocol was found to be highly regio- and chemoselective and presented broad functional group tolerance

    Sc<sup>3+</sup>-Triggered Oxoiron(IV) Formation from O<sub>2</sub> and its Non-Heme Iron(II) Precursor via a Sc<sup>3+</sup>–Peroxo–Fe<sup>3+</sup> Intermediate

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    We report that redox-inactive Sc<sup>3+</sup> can trigger O<sub>2</sub> activation by the Fe<sup>II</sup>(TMC) center (TMC = tetramethylcyclam) to generate the corresponding oxoiron­(IV) complex in the presence of BPh<sub>4</sub><sup>–</sup> as an electron donor. To model a possible intermediate in the above reaction, we generated an unprecedented Sc<sup>3+</sup> adduct of [Fe<sup>III</sup>(η<sup>2</sup>-O<sub>2</sub>)­(TMC)]<sup>+</sup> by an alternative route, which was found to have an Fe<sup>3+</sup>–(μ-η<sup>2</sup>:η<sup>2</sup>-peroxo)–Sc<sup>3+</sup> core and to convert to the oxoiron­(IV) complex. These results have important implications for the role a Lewis acid can play in facilitating O–O bond cleavage during the course of O<sub>2</sub> activation at non-heme iron centers

    Cell-free DNA: A Neglected Source for Antibiotic Resistance Genes Spreading from WWTPs

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    Cell-associated ARGs in wastewater treatment plants (WWTPs) has been concerned, however, cell-free ARGs in WWTPs was rarely studied. In this study, the abundances of four representative ARGs, <i>sulII</i>, <i>tetC</i>, <i>bla</i><sub><i>PSE‑1</i></sub>, and <i>ermB</i>, in a large municipal WWTP were investigated in both cell-associated and cell-free fractions. Cell-associated ARGs was the dominant ARGs fraction in the raw wastewater. After biological treatment, sludge settling, membrane filtration, and disinfection, cell-associated ARGs were substantially reduced, though the ratios of ARG/16S rRNA gene were increased with disinfection. Cell-free ARGs persisted in the WWTP with a removal of 0.36 log to 2.68 logs, which was much lower than the removal of cell-associated ARGs (3.21 logs to 4.14 logs). Therefore, the abundance ratio of cell-free ARGs to cell-associated ARGs increased from 0.04–1.59% to 2.00–1895.08% along the treatment processes. After 25-day-storage, cell-free ARGs in both biological effluent and disinfection effluent increased by 0.14 log to 1.99 logs and 0.12 log to 1.77 logs respectively, reflecting the persistence and low decay rate of cell-free ARGs in the discharge water. Therefore, cell-free ARGs might be a kind of important but previously neglected pollutant from WWTPs, which added potential risks to the effluent receiving environments

    Metal-Free Assembly of Polysubstituted Pyridines from Oximes and Acroleins

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    Transition-metal-catalyzed synthesis of N-heterocycles from oximes has been previously well established. In this paper, for the first time a metal-free protocol with the combinational employment of iodine and triethylamine has been demonstrated to be effective to trigger the oxime-based synthesis of pyridines with high chemo-selectivity and wide functional group tolerance. A broad range of functional pyridines were prepared in moderate to excellent yields. While neither iodine nor triethylamine could trigger this transformation, mechanistic experiments indicated a radical pathway for the reaction. The resultant 2-aryl-substituted pyridines have been proved to be versatile building blocks in a range of transition-metal-catalyzed C–H functionalization reactions
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