磁性核-壳二氧化钛纳米颗粒(Fe 3 O 4 @SiO 2 @TiO 2)可通过各种浓度的醛,二甲酮和丙二腈的一锅三组分缩合反应有效地用于制备四氢苯并[ b ]吡喃衍生物。无溶剂条件下的℃。通过几种技术合成并表征了催化剂,包括X射线衍射(XRD),透射电子显微镜(TEM),场发射扫描电子显微镜(FESEM)和能量色散X射线光谱(EDX)。
Magnetic core–shell titanium dioxide nanoparticles as an efficient catalyst for domino Knoevenagel–Michael-cyclocondensation reaction of malononitrile, various aldehydes and dimedone
Magnetic core–shell titaniumdioxide nanoparticles (Fe3O4@SiO2@TiO2) were efficiently used for the preparation of tetrahydrobenzo[b]pyran derivatives via a one-pot three component condensation reaction of various aldehydes, dimedone and malononitrile at 100 °C under solvent-free conditions. The catalyst was synthesized and characterized by several techniques including X-ray diffraction (XRD), transmission
磁性核-壳二氧化钛纳米颗粒(Fe 3 O 4 @SiO 2 @TiO 2)可通过各种浓度的醛,二甲酮和丙二腈的一锅三组分缩合反应有效地用于制备四氢苯并[ b ]吡喃衍生物。无溶剂条件下的℃。通过几种技术合成并表征了催化剂,包括X射线衍射(XRD),透射电子显微镜(TEM),场发射扫描电子显微镜(FESEM)和能量色散X射线光谱(EDX)。
A green one-pot three-component synthesis of tetrahydrobenzo[b]pyran and 3,4-dihydropyrano[c]chromene derivatives using a Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>–imid–PMA<sup>n</sup> magnetic nanocatalyst under ultrasonic irradiation or reflux conditions
An efficient and environmentallybenign procedure for the synthesis of tetrahydrobenzo[b]pyran and 3,4-dihydropyrano[c]chromene derivatives has been developed by a one-pot three-component reaction of various aldehydes, malononitrile, and dimedone or hydroxycoumarin in the presence of Fe3O4@SiO2–imid–PMAn nanoparticles as magnetic catalysts under ultrasonic irradiation or reflux conditions in water
通过在锅中各种醛,丙二腈,二甲酮或羟基香豆素的一锅三组分反应,开发了一种有效的,对环境无害的合成四氢苯并[ b ]吡喃和3,4-二氢吡喃并[ c ]色烯衍生物的方法。 Fe 3 O 4 @SiO 2-亚胺基-PMA n的存在超声辐射或水中回流条件下,纳米颗粒作为磁性催化剂。该新方法具有显着的优点,例如操作简单,产率高,反应时间短以及无需任何繁琐的后处理或纯化。另外,在水介质中的优异催化性能以及催化剂的易于制备,热稳定性和分离使其成为良好的非均相体系,并且是其他非均相催化剂的有用替代品。同样,该催化剂可以很容易地通过磁场回收并在连续的八个反应循环中重复使用而没有明显的活性损失。
Introducing rGO@Fe
<sub>3</sub>
O
<sub>4</sub>
@Ni as an efficient magnetic nanocatalyst for the synthesis of tetrahydrobenzopyranes via multicomponent coupling reactions of dimedone, malononitrile, and aromatic aldehydes
作者:Mozhgan Esmati、Behzad Zeynizadeh
DOI:10.1002/aoc.6496
日期:2022.2
rGO@Fe3O4@Ni as the efficientmagneticnanocatalyst was applied to expedite the multicomponent coupling reactions (MCRs) of dimedone, malononitrile, and structurally diverse aromatic aldehydes to prepare tetrahydrobenzopyranes. All reactions were fulfilled efficiently in deionized water under reflux conditions. In addition, sustainability of the nanocatalyst was examined for five consecutive reaction cycles without
在这项研究中,研究了改性 GO 和 rGO@Fe 3 O 4 @Ni 复合体系的合成和表征。傅里叶变换红外光谱 (FT-IR)、扫描电子显微镜 (SEM)、透射电子显微镜 (TEM)、能量色散 X 射线光谱 (EDX)、X 射线粉末衍射 (XRD)、振动样品磁力计 (VSM) )、Brunauer-Emmett-Teller (BET) 分析、热重分析 (TGA) 和电感耦合等离子体发射光谱 (ICP-OES) 用于表征制备的纳米材料。此外,还比较了 GO、rGO@Fe 3 O 4、rGO@Ni 和 rGO@Fe 3 O 4 @Ni 和 rGO @Fe 3 O的催化活性。4 @Ni 作为高效的磁性纳米催化剂被应用于加速二甲酮、丙二腈和结构多样的芳香醛的多组分偶联反应 (MCR) 以制备四氢苯并吡喃。所有反应均在去离子水中在回流条件下有效地进行。此外,纳米催化剂的可持续性在五个连续的反应循环
Tandem Knoevenagel–Michael-cyclocondensation reactions of malononitrile, various aldehydes and dimedone using acetic acid functionalized ionic liquid
of malononitrile, dimedone and variousaldehydes in the presence of acetic acidfunctionalized imidazolium salts (1-carboxymethyl-3-methylimidazolium bromide [cmmim]Br} and 1-carboxymethy1-3-methylimidazolium tetrafluoroborate [cmmim][BF4]}) as reusable catalysts has been reported. The turn over frequency (TOF) values of the catalysts are higher than some of the previously reported catalysts. Also
在乙酸官能化的咪唑鎓盐(1-羧甲基-3-甲基咪唑鎓溴化[cmmim] Br}和乙酸)存在下,通过丙二腈,二甲酮和各种醛的缩合合成四氢苯并[ b ]吡喃的有效无溶剂方案。已经报道了作为可重复使用的催化剂的1-羧基甲基1-3-甲基咪唑鎓四氟硼酸酯([cmmim] [BF 4 ]})。催化剂的周转频率(TOF)值高于某些先前报道的催化剂。此外,这项工作还报告了热重分析(TGA),差示热重分析(DTG),X射线衍射分析(XRD)以及催化剂尺寸和晶面间距的计算。
Design, preparation and characterization of Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>@ECH@thiocarbazide@Au(<scp>i</scp>)@chitosan nanoparticles as a catalyst for the synthesis of 3,4-dihydropyrano[3,2-<i>c</i>]chromenes
作者:Elahe Gholamiyan Karkon、Hossein Mostafavi
DOI:10.1039/d2nj05229f
日期:——
Magnetic iron/silica/linker/gold ions/chitosan nanostructures were synthesized to achieve an efficient and reusable catalyst characterized by X-ray diffraction, scanning and transmission electron microscopies, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, vibrating sample magnetometry, and inductively coupled plasma optical emission spectrometry
合成了磁性铁/二氧化硅/连接剂/金离子/壳聚糖纳米结构以获得高效且可重复使用的催化剂,其特征在于 X 射线衍射、扫描和透射电子显微镜、能量色散 X 射线光谱、热重分析、傅立叶变换红外光谱、振动样品磁力测定法和电感耦合等离子体发射光谱法。为了提高它们的稳定性并增加它们的表面,将获得的多层纳米复合材料封装在壳聚糖和戊二醛网络中。发现所获得的纳米颗粒具有43至72nm的直径尺寸。优化的纳米催化剂用于合成 3,4-二氢吡喃[3,2- c]室温下水中的芳香醛或芳香乙二醛、丙二腈和环己烷-1,3-二酮中的色烯。所制备的纳米催化剂可以通过使用外部磁铁快速回收并重复使用多次而不会显着损失活性。