A practical and highly efficientsilylation of alcohol and phenol derivatives with hexamethyldisilazane (HMDS) using acidic ionic liquids undermild reaction conditions is described. A series of Brønsted as well as Brønsted–Lewis acidic ionic liquids were prepared and their performance investigated for the silylation of a wide variety of alcohols and phenols with HMDS. Imidazole‐ as well as N‐meth
Preparation and characterization of a RHA/TiO<sub>2</sub>nanocomposite: introduction of an efficient and reusable catalyst for chemoselective trimethylsilyl protection and deprotection of alcohols and phenols
nanoparticles leading to the RHA/TiO2 nanocomposite. This nanocomposite was used as an efficientcatalyst for the chemoselective trimethylsilylation of various alcohols and phenols and deprotection of the obtained trimethylsilyl ethers. The procedure gave the products in excellent yields in very short reaction times. Also this catalyst can be reused at least six times without loss of its catalytic activity.
在这项工作中,稻壳灰(RHA)作为无定形二氧化硅的天然来源,被用作合成RHA / TiO 2纳米复合材料的锐钛矿相二氧化钛纳米粒子的载体。该纳米复合材料用作各种醇和酚的化学选择性三甲基甲硅烷基化和所得三甲基甲硅烷基醚的脱保护的有效催化剂。该程序在非常短的反应时间内以优异的产率获得了产物。同样,该催化剂可以重复使用至少六次,而不会损失其催化活性。
Synthesis and characterization of a bifunctional nanomagnetic solid acid catalyst (Fe<sub>3</sub>
O<sub>4</sub>
@CeO<sub>2</sub>
/SO<sub>4</sub>
<sup>2−</sup>
) and investigation of its efficiency in the protection process of alcohols and phenols via hexamethyldisilazane under solvent-free conditions
synthesized using the coprecipitation method and functionalized by an ammonium sulfate solution to achieve a heterogeneous solid acid Fe3O4@CeO2/SO42− (FCA) catalyst. The synthesized bifunctional catalyst was used in the protection process of alcohols and phenols using hexamethyldisilazane (HMDS) at ambient temperature undersolvent‐free conditions. Due to its excellent magnetic properties, FCA can easily be
在这项研究中,使用共沉淀法合成了Fe 3 O 4 @CeO 2(FC),并通过硫酸铵溶液对其进行了功能化处理,从而获得了非均相的固体酸Fe 3 O 4 @CeO 2 / SO 4 2-(FCA)催化剂。合成的双功能催化剂在环境温度和无溶剂条件下使用六甲基二硅氮烷(HMDS)用于醇和酚的保护过程。由于其优异的磁性,FCA可以很容易地从反应混合物中分离出来并重复使用几次,而不会显着降低其催化活性。纳米催化剂的优异的收率和选择性,简单的分离,低成本和高可回收性是该方法的突出优点。使用不同技术进行表征,例如傅立叶变换红外光谱(FT-IR),扫描电子显微镜(SEM),能量色散X射线光谱(EDX),X射线衍射(XRD)和振动样品磁强计( VSM)。
Poly(4-vinylpyridine) catalyzed chemoselective O-TMS protection of alcohols and phenols and N-Boc protection of amines
作者:Farhad Shirini、Nader Ghaffari Khaligh
DOI:10.1007/s13738-011-0060-5
日期:2012.8
Poly(4-vinylpyridine) (PVP) acts as an efficient and reusable catalyst for the selective and efficient trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) and N-tert-butoxycarbonylation of amines with (Boc)2O. All reactions were performed under mild conditions in good to high yields.
Nanomagnetic zirconia-based sulfonic acid (Fe<sub>3</sub>O<sub>4</sub>@ZrO<sub>2</sub>-Pr-SO<sub>3</sub>H): a new, efficient and recyclable solid acid catalyst for the protection of alcohols via HMDS under solvent free conditions
alcohols using hexamethyldisilazane (HMDS) under solvent-free conditions at room temperature. The solid nanocatalyst can easily be separated and reused several times without significant loss of its catalytic activity. Also, in addition to its being inexpensive and the simplicity of the separation process, this heterogeneouscatalyst has shown a good chemoselectivity in the reactions.
在本工作中,通过(3-巯基丙基)三甲氧基硅烷与纳米磁性氧化锆的反应来制备磺酸官能化的纳米磁性氧化锆。然后,通过过氧化氢和H 2 SO 4直接氧化硫醇基,合成了纳米氧化锆基磺酸(Fe 3 O 4 @ZrO 2 -Pr -SO 3 H)。随后。通过傅里叶变换红外光谱(FT-IR),场发射扫描电子显微镜(FE-SEM)成像,能量色散X射线光谱(EDX),X射线衍射(XRD)测量和振动样品磁力分析法对催化剂进行了表征( VSM)。六甲基二硅氮烷(HMDS)在无溶剂条件下于室温下用作具有高催化活性的有效纳米催化剂,用于保护醇。固体纳米催化剂可以容易地分离并重复使用数次,而不会显着降低其催化活性。而且,除了其廉价和分离过程的简便性之外,这种非均相催化剂在反应中还显示出良好的化学选择性。