14 research outputs found

    Synthesis of 1‑Aminoisoquinolines by Gold(III)-Mediated Domino Reactions from 2‑Alkynylbenzamides and Ammonium Acetate

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    A facile synthetic route toward pharmaceutically interesting 1-aminoisoquinoline derivatives by gold­(III)-mediated domino reactions is described. This synthetic protocol starts from readily available 2-alkynylbenzamides and ammonium acetate and takes place under mild reaction conditions compatible with a variety of functional groups. A plausible mechanism for the domino process is proposed, supported by the reaction of a possible intermediate, <i>N</i>-(3-phenyl-1<i>H</i>-isochromen-1-ylidene)­propan-1-amine

    Combination of Bioinspiration: A General Route to Superhydrophobic Particles

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    We combine two amazing abilities found in nature: the superhydrophobic property of lotus leaf and the adhesive ability of mussel adhesive protein. The molecular structure mimic of the single units of adhesive proteins, dopamine, was polymerized in an alkaline aqueous solution to encapsulate microparticles. The as-formed thin polydopamine walls worked as reactive templates to generate silver nanoparticles on the capsuled particles. As a result, core/shell/satellite composite particles were generated with a hierarchical structure similar to the micromorphology of lotus leaf. The composite particles exhibited extremely water repellence after fluorination. Because dopamine can deposit and adhere to all kinds of materials, this method can be applied to diverse microparticles, from organic to inorganic. In addition, particles of different sizes and matters can be modified to superhydrophobic particles in one pot. Magnetic particles have also been prepared which could be used as oil-absorbent and magnetic controlled carriers. “Oil marbles” formed underwater were achieved for the first time

    Gold-Catalyzed Ammonium Acetate Assisted Cascade Cyclization of 2‑Alkynylarylketones

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    An ammonium acetate assisted gold-catalyzed cascade cyclization reaction of 2-alkynylaryl­ketones is described. Under the reported conditions, a gold-catalyzed intramolecular cyclization of 2-alkynylaryl­ketones takes place through two competing reaction mechanismsa 5-<i>exo</i>-<i>dig</i> or a 6-<i>endo</i>-<i>dig</i> cyclizationleading to two regioisomeric intermediates: isobenzofuranium or isobenzopyrylium. In the presence of ammonium acetate, the two intermediate compounds undergo further rearrangement to 2,3-disubstituted indenones and 1,3-disubstituted isoquinolines, respectively. While both reaction pathways proceed via a cyclization–rearrangement cascade, the gold-mediated 5-<i>exo</i>-<i>dig</i> process is especially notable, as it provides a novel cyclization protocol of 2-alkynylaryl­ketones

    Platinum(II)-Catalyzed Asymmetric Ring-Opening Addition of Arylboronic Acids to Oxabenzonorbornadienes

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    A new platinum­(II)-catalyzed asymmetric ring-opening addition of arylboronic acids to oxabenzonorbornadienes was developed, which afforded the corresponding <i>cis</i>-2-aryl-1,2-dihydronaphthalen-1-ol products in high yields (up to 97%) with moderate to good enantioselectivities (up to 89% ee) under very mild conditions. The effects of various ligands, catalyst loading, bases, solvents, and temperatures on the yield and enantioselectivity of the reaction were also investigated. The cis configuration of product <b>2m</b> was confirmed by X-ray diffraction analysis. A potential mechanism for the present catalytic reaction is proposed

    Iridium-Catalyzed Asymmetric Ring-Opening of Azabicyclic Alkenes with Phenols

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    The asymmetric ring-opening of azabicyclic alkenes with a variety of phenols is investigated using an iridium catalyst generated in situ from 2.5 mol % of [Ir­(COD)­Cl]<sub>2</sub> and 5.0 mol % of (<i>S</i>)-BINAP, which afforded the corresponding 1,2-<i>trans</i>-phenoxyamino products in excellent yield (up to 92%) with moderate to good enantioselectivities (up to 98% ee). The <i>trans</i>-configuration of the product <b>4b</b> was confirmed by X-ray crystallography

    Nickel-Catalyzed Asymmetric Ring Opening of Oxa­benzo­norborna­dienes with Arylboronic Acids

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    A new, versatile, and highly efficient nickel-catalyzed asymmetric ring-opening (ARO) reaction of oxabenzo­norborna­dienes with a wide variety of arylboronic acids has been developed, yielding <i>cis</i>-2-aryl-1,2-dihydro­naph­thalen-1-ols in high yields (up to 99%) with good to excellent enantioselectivities (up to 99% ee) under very mild conditions. The effects of various nickel precursors, chiral bidentate ligands, catalyst loadings, bases, solvents, and temperatures on the yield and enantioselectivity of the reaction were also investigated. A plausible mechanism was proposed to account for the formation of the corresponding <i>cis</i>-ring-opened products based on the X-ray structure of product <b>4b</b>

    Platinum(II)-Catalyzed Asymmetric Ring-Opening Addition of Arylboronic Acids to Oxabenzonorbornadienes

    No full text
    A new platinum­(II)-catalyzed asymmetric ring-opening addition of arylboronic acids to oxabenzonorbornadienes was developed, which afforded the corresponding <i>cis</i>-2-aryl-1,2-dihydronaphthalen-1-ol products in high yields (up to 97%) with moderate to good enantioselectivities (up to 89% ee) under very mild conditions. The effects of various ligands, catalyst loading, bases, solvents, and temperatures on the yield and enantioselectivity of the reaction were also investigated. The cis configuration of product <b>2m</b> was confirmed by X-ray diffraction analysis. A potential mechanism for the present catalytic reaction is proposed

    Directional and Path-Finding Motion of Polymer Hydrogels Driven by Liquid Mixing

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    The spreading of a miscible liquid with a low surface tension on a water surface generates the directional motion of submerged polymer hydrogels, which could be attributed to convective flows resulting from the gradient of surface tension along the surface (Marangoni effect). The direction and velocity of this motion can be well controlled by altering the driving conditions. Furthermore, a spherical hydrogel can smartly find the path to walk through a microfluidic maze when liquid mixing occurs near the maze exit. This convenient chemical driving approach to transporting submerged objects in a desired way may be useful in microfluidics, micromechanics, and other applications

    Cytotoxic and Antibacterial Preussomerins from the Mangrove Endophytic Fungus <i>Lasiodiplodia theobromae</i> ZJ-HQ1

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    Two new chlorinated preussomerins, chloropreussomerins A and B (<b>1</b> and <b>2</b>), together with nine known preussomerin analogues, <b>3</b>–<b>11</b>, were obtained from the endophytic fungus <i>Lasiodiplodia theobromae</i> ZJ-HQ1. Their structures were elucidated by a combination of spectroscopic analyses. The absolute configurations of <b>1</b> and <b>2</b> were both determined by single-crystal X-ray diffraction using Cu Kα radiation. Chloropreussomerins A and B (<b>1</b> and <b>2</b>) are the first chlorinated compounds in the preussomerin family, and preussomerin M (<b>3</b>) is reported for the first time as a natural product. Compounds <b>1</b> and <b>2</b> showed potent <i>in vitro</i> cytotoxicity against A549 and MCF-7 human cancer cell lines, with IC<sub>50</sub> values ranging from 5.9 to 8.9 μM, and compounds <b>4</b>–<b>7</b> exhibited significant bioactivity against A549, HepG2, and MCF-7 human cancer cell lines, with IC<sub>50</sub> values of 2.5–9.4 μM. In the antibacterial assay, compounds <b>1</b>, <b>2</b>, <b>5</b>–<b>7</b>, and <b>11</b> exhibited significant activities against <i>Staphylococcus aureus</i>, with MIC values between 1.6 and 13 μg/mL

    Platinum-Catalyzed Asymmetric Ring-Opening Reactions of Oxabenzonorbornadienes with Phenols

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    A platinum­(II)-catalyzed asymmetric ring opening of oxabenzonorbornadienes with phenols was developed, which afforded the corresponding <i>cis</i>-2-(un)­substituted phenoxy-1,2-dihydronaphthalen-1-ol products rather than the <i>trans</i> ones in excellent yields (up to 99%) with moderate to good enantioselectivities (up to 87% ee) under mild conditions. In addition, the <i>cis</i>-configuration of product <b>2b</b> was confirmed by X-ray diffraction analysis. Based on the results, a potential mechanism for the present catalytic reaction was proposed
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