Sulfonated rice husk ash (RHA-SO3H), a newly reported solid acid catalyst, was efficiently used for the synthesis of 4,4′-(arylmethylene)-bis-(3-methyl-1-phenyl-1H-pyrazol-5-ols), 3,3′-(arylmethylene)-bis-(4-hydroxycoumarins) and bis(indolyl)methanes. The procedure gave the products in excellent yields within very short reaction times under mild and green conditions. Also this catalyst can be reused several times without appreciable loss of its catalytic activity.
Melamine trisulfunic acid is employed as a recyclable catalyst for the condensation reaction of aromatic aldehydes with 3‐methyl‐l‐phenyl‐2‐pyrazolin‐5‐one. This condensation reaction was performed in ethanol under refluxing conditions giving 4,4′‐(arylmethylene)‐bis‐(3‐methyl‐1‐phenyl‐1H‐pyrazol‐5‐ols) in 80‐96% yields.
Non-Covalent Supported of l-Proline on Graphene Oxide/Fe3O4 Nanocomposite: A Novel, Highly Efficient and Superparamagnetically Separable Catalyst for the Synthesis of Bis-Pyrazole Derivatives
A superparamagnetic grapheneoxide/Fe₃O₄/l-proline nano hybrid that was obtained from the non-covalent immobilization of l-proline on grapheneoxide/Fe₃O₄ nanocomposite was used as a new magnetically separable catalyst for the efficient synthesis of 4,4'-(arylmethylene)bis(1H-pyrazol-5-ol) derivatives. The prepared heterogeneouscatalyst was characterized using FTIR, TGA, DTG, XRD, TEM, SEM, and elemental
通过将l-脯氨酸非共价固定在氧化石墨烯/ Fe 3 O 3纳米复合材料上获得的超顺磁性氧化石墨烯/ Fe 3 O 3 / l-脯氨酸纳米杂化物被用作一种新型的可磁分离的催化剂,用于有效合成4,4'-(芳基亚甲基)双(1H-吡唑-5-醇)衍生物。使用FTIR,TGA,DTG,XRD,TEM,SEM和元素分析技术对制备的多相催化剂进行了表征。较短的反应时间(5-15分钟),极好的收率(87-98%)和简单的实验步骤以及易于后处理的优点是引入的催化剂的一些优点。
Design and Characterization of l-Prolinate-Amberlite as a Novel Heterogeneous Organocatalyst and Its Catalytic Application in the Synthesis of Pyrazol-Derivates
作者:Mosadegh Keshavarz、Masoumeh Vafaei-Nezhad
DOI:10.1007/s10562-015-1668-3
日期:2016.2
The [Amb]l-prolinate obtained from the immobilization of l-prolinateanionontoamberlite IRA900OH, was used as a new organocatalyst for the efficientsynthesis of 4,4′-(arylmethylene)-bis-(1H-pyrazol-5-ol) derivatives. The prepared heterogeneousorganocatalyst was well characterized by using of FTIR, TGA, DTG, XRD and elemental analysis techniques. Short reaction times (5–18 min), excellent yields
Silica Sulfuric Acid, an Efficient and Recyclable Solid Acid Catalyst for the Synthesis of 4,4′-(Arylmethylene)bis (1<i>H</i>-pyrazol-5-ols)
作者:Khodabakhsh Niknam、Salimeh Mirzaee
DOI:10.1080/00397911.2010.502999
日期:2011.8.15
Abstract Silica sulfuricacid (SSA) is employed as a recyclablecatalyst for the condensation reaction of aromatic aldehydes with 3-methyl-l-phenyl-5-pyrazolone. This condensation reaction is performed in a mixture (1:1 v/v) of water–ethanol at 70 °C, giving 4,4′-alkylmethylene-bis(3-methyl-5-pyrazolones) in 75–93% yields.