15 research outputs found

    [3 + 1]- and [3 + 2]-Cycloadditions of Azaoxyallyl Cations and Sulfur Ylides

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    A new formal [3 + 1]-cycloaddition reaction of azaoxyallyl cation intermediates, generated in situ from α-halo hydroxamates bearing α-alkyl groups, and sulfur ylides is reported, furnishing useful β-lactams (dr >19:1) in fair to modest yields. In contrast, an unexpected formal [3 + 2]-cycloaddition reaction occurs to give γ-lactam derivatives for α-halo hydroxamates with α-aryl groups and sulfur ylides in the presence of bases

    [3 + 1]- and [3 + 2]-Cycloadditions of Azaoxyallyl Cations and Sulfur Ylides

    No full text
    A new formal [3 + 1]-cycloaddition reaction of azaoxyallyl cation intermediates, generated in situ from α-halo hydroxamates bearing α-alkyl groups, and sulfur ylides is reported, furnishing useful β-lactams (dr >19:1) in fair to modest yields. In contrast, an unexpected formal [3 + 2]-cycloaddition reaction occurs to give γ-lactam derivatives for α-halo hydroxamates with α-aryl groups and sulfur ylides in the presence of bases

    Asymmetric Diels–Alder Reaction of 2‑Methyl-3-indolylmethanols via in Situ Generation of <i>o</i>‑Quinodimethanes

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    An asymmetric Diels–Alder reaction of 2-methyl-3-indolylmethanols and α,β-unsaturated aldehydes has been developed that relies on in situ generation of active indole-2,3-quinodimethane intermediates under mild acidic conditions and uses a secondary chiral amine as iminium activation catalyst. An array of highly enantioenriched tetrahydrocarbazoles have been efficiently produced in fair to good yields

    Asymmetric Diels–Alder Reaction of 2‑Methyl-3-indolylmethanols via in Situ Generation of <i>o</i>‑Quinodimethanes

    No full text
    An asymmetric Diels–Alder reaction of 2-methyl-3-indolylmethanols and α,β-unsaturated aldehydes has been developed that relies on in situ generation of active indole-2,3-quinodimethane intermediates under mild acidic conditions and uses a secondary chiral amine as iminium activation catalyst. An array of highly enantioenriched tetrahydrocarbazoles have been efficiently produced in fair to good yields

    Enantioselective [4 + 1] Annulation Reactions of α‑Substituted Ammonium Ylides To Construct Spirocyclic Oxindoles

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    Ammonium ylides have a long history in organic synthesis, but their application in asymmetric catalysis is still underdeveloped in regard to both substrate scope and reaction pathways compared with phosphorus and sulfur ylides. Here a previously unreported asymmetric [4 + 1] annulation reaction of 3-bromooxindoles and electron-deficient 1-azadienes has been developed through ammonium ylide catalysis of a newly designed 2′-methyl α-isocupreine (α-MeIC), efficiently delivering spirocyclic oxindole compounds incorporating a dihydropyrrole motif in excellent enantioselectivity (up to 99% ee). To the best of our knowledge, this work represents the first example of asymmetric catalysis of ammonium ylides bearing α-substitutions, and the catalytic [4 + 1] annulation pathway of ammonium ylides is also unprecedented. Moreover, <sup>1</sup>H NMR, mass spectroscopy, and computational calculation studies were conducted, and the catalytic cycle and a tentative explanation of the enantioselective mechanism have been successfully elucidated

    Enantioselective [4 + 1] Annulation Reactions of α‑Substituted Ammonium Ylides To Construct Spirocyclic Oxindoles

    No full text
    Ammonium ylides have a long history in organic synthesis, but their application in asymmetric catalysis is still underdeveloped in regard to both substrate scope and reaction pathways compared with phosphorus and sulfur ylides. Here a previously unreported asymmetric [4 + 1] annulation reaction of 3-bromooxindoles and electron-deficient 1-azadienes has been developed through ammonium ylide catalysis of a newly designed 2′-methyl α-isocupreine (α-MeIC), efficiently delivering spirocyclic oxindole compounds incorporating a dihydropyrrole motif in excellent enantioselectivity (up to 99% ee). To the best of our knowledge, this work represents the first example of asymmetric catalysis of ammonium ylides bearing α-substitutions, and the catalytic [4 + 1] annulation pathway of ammonium ylides is also unprecedented. Moreover, <sup>1</sup>H NMR, mass spectroscopy, and computational calculation studies were conducted, and the catalytic cycle and a tentative explanation of the enantioselective mechanism have been successfully elucidated

    Additional file 4: Figure S3. of Tripartite motif containing 62 is a novel prognostic marker and suppresses tumor metastasis via c-Jun/Slug signaling-mediated epithelial-mesenchymal transition in cervical cancer

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    The expression level of cell cycle related proteins CyclinD1 and P27. Beta-actin was used as a loading control. (A) Western blot detected the expression level of CyclinD1 and P27 in CC cells with or without TRIM62 overexpression. (B) Expression level of CyclinD1 and P27 in SiHa-NC, SiHa-TRIM62, SiHa-TRIM62 + c-Jun, HeLa-NC, HeLa-TRIM62 and HeLa-TRIM62 + c-Jun cells were detected by western blot. (TIF 372 kb

    Baicalein Inhibits Progression of Gallbladder Cancer Cells by Downregulating ZFX

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    <div><p>Baicalein, a widely used Chinese herbal medicine, has multiple pharmacological activities. However, the precise mechanisms of the anti-proliferation and anti-metastatic effects of baicalein on gallbladder cancer (GBC) remain poorly understood. Therefore, the aim of this study was to assess the anti-proliferation and anti-metastatic effects of baicalein and the related mechanism(s) on GBC. In the present study, we found that treatment with baicalein induced a significant inhibitory effect on proliferation and promoted apoptosis in GBC-SD and SGC996 cells, two widely used gallbladder cancer cell lines. Additionally, treatment with baicalein inhibited the metastasis of GBC cells. Moreover, we demonstrated for the first time that baicalein inhibited GBC cell growth and metastasis via down-regulation of the expression level of Zinc finger protein X-linked (ZFX). In conclusion, our studies suggest that baicalein may be a potential phytochemical flavonoid for therapeutics of GBC and ZFX may serve as a molecular marker or predictive target for GBC.</p></div
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