16 research outputs found

    FeCl<sub>3</sub>‑Catalyzed Four-Component Nucleophilic Addition/Intermolecular Cyclization Yielding Polysubstituted Pyridine Derivatives

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    We report an efficient route to pyridine derivatives via an FeCl<sub>3</sub>-catalyzed four-component nucleophilic addition/intermolecular cyclization. This simple fragment assembly strategy uses mild conditions and affords a broad range of polysubstituted pyridines in moderate to good yield from simple and readily available starting materials. A plausible mechanism for this process is proposed

    FeCl<sub>3</sub>‑Mediated Synthesis of β‑Alkynyl Ketones via Domino Nucleophilic-Substitution/Intramolecular-Cyclization/Reverse Claisen Condensation of <i>N</i>‑Cyclohexyl Propargylamines and 1,3-Diketones

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    The synthesis of β-alkynyl ketones was achieved in good to excellent yields by an iron-catalyzed domino reaction of <i>N</i>-cyclohexyl propargylamines and 1,3-diketones. A plausible mechanism involving nucleophilic substitution, intramolecular cyclization, and reverse Claisen condensation for this process is proposed

    Dendrogram displaying the PFGE profiles of the 43 isolates.

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    <p>The strain number, origin, source, sequence type (ST), and H<sub>2</sub>S phenotype are shown for each strain. +, H<sub>2</sub>S-producing isolate; −, non-H<sub>2</sub>S-producing isolate.</p

    Sequence alignment of the <i>phs</i> gene and the protein.

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    <p>A nonsense mutation at position 208 of the <i>phsA</i> gene results in the replacement of a sense codon (CAG) with a termination codon (UAG) leading to the premature termination of <i>phsA</i>. The first sequence, <i>phsA</i>, is based on <i>S</i>. enterica serotype Typhimurium strain LT2 (GenBank AE006468). *, termination codon; +, H<sub>2</sub>S-producing isolate; −, non-H<sub>2</sub>S-producing isolate.</p

    Additional file 1: of Antibiotic resistance and molecular characterization of the hydrogen sulfide-negative phenotype among diverse Salmonella serovars in China

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    Table S1. Reference strains for phs operon sequence analysis. Table S2. GenBank accession numbers for phs operon sequences from 46 H2S-negative Salmonella isolates. Table S3. Mutations detected in the phsB and phsC genes of H2S-negative Salmonella isolates. (DOC 71 kb

    An outbreak of acute respiratory disease caused by a virus associated RNA II gene mutation strain of human adenovirus 7 in China, 2015

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    <div><p>Human adenovirus 7 (HAdV-7) strains are a major cause of acute respiratory disease (ARD) among adults and children, associated with fatal pneumonia. An ARD outbreak caused by HAdV-7 that involved 739 college students was reported in this article. To better understand the underlying cause of this large-scale epidemic, virus strains were isolated from infected patients and sequence variations of the whole genome sequence were detected. Evolutionary trees and alignment results indicated that the major capsid protein genes hexon and fibre were strongly conserved among serotype 7 strains in China at that time. Instead, the HAdV-7 strains presented three thymine deletions in the virus associated RNA (VA RNA) II terminal region. We also found that the mutation might lead to increased mRNA expression of an adjacent gene, L1 52/55K, and thus promoted faster growth. These findings suggest that sequence variation of VA RNA II gene was a potential cause of such a severe HAdV-7 infection and this gene should be a new-emerging factor to be monitored for better understanding of HAdV-7 infection.</p></div