A Simple, Efficient and Green Procedure for the Knoevenagel Condensation of Aldehydes with N-Methylpiperazine at Room Temperature under Solvent-Free Conditions
作者:Chhanda Mukhopadhyay、Arup Datta
DOI:10.1080/00397910802029364
日期:2008.6.20
Abstract Knoevenagelcondensation of aromatic, aliphatic, and heteroaromatic aldehydes with active methylene compounds such as ethylcyanoacetate, malononitrile, and cyanoacetamide proceed very smoothly at room temperature by simply mixing the ingredients together undersolvent-freeconditions in the presence of N-methylpiperazine in excellent yields of the E-configured products.
摘要 芳香族、脂肪族和杂芳香族醛与活性亚甲基化合物如氰乙酸乙酯、丙二腈和氰基乙酰胺的 Knoevenagel 缩合在室温下非常顺利地进行,方法是在 N-甲基哌嗪的存在下,在无溶剂条件下简单地将这些成分混合在一起,收率非常好的 E 配置产品。
The Knoevenagel condensation using quinine as an organocatalyst under solvent-free conditions
作者:Kavita Jain、Saikat Chaudhuri、Kuntal Pal、Kalpataru Das
DOI:10.1039/c8nj04219e
日期:——
organocatalyst to afford various electrophilic alkenes in excellent yields (up to 90%). In the presence of a catalytic amount of quinine (15 mol%), the reaction proceeded at room temperature (RT) undersolvent-freeconditions. In this green approach, the organocatalyst was recovered and recycled for up to four cycles without appreciable loss of activity.
Tri-lacunary polyoxometalates of Na8H[PW9O34] as heterogeneous Lewis base catalysts for Knoevenagel condensation, cyanosilylation and the synthesis of benzoxazole derivatives
作者:Shen Zhao、Yang Chen、Yu-Fei Song
DOI:10.1016/j.apcata.2014.01.017
日期:2014.4
development of tri-lacunary polyoxometalates (POMs) of Na8H[A-PW9O34]·7H2O and Na8H[B-PW9O34]·19H2O (Na-A-PW9 and Na-B-PW9) as highlyselective and efficient heterogeneous Lewis base catalysts for Knoevenagel condensation, cyanosilylation of various aldehydes and ketones and the synthesis of benzoxazole derivatives at 25 °C under mild conditions. Since both Na-A-PW9 and Na-B-PW9 display no characteristic porosity
Classical Keggin Intercalated into Layered Double Hydroxides: Facile Preparation and Catalytic Efficiency in Knoevenagel Condensation Reactions
作者:Yueqing Jia、Yanjun Fang、Yingkui Zhang、Haralampos N. Miras、Yu-Fei Song
DOI:10.1002/chem.201501953
日期:2015.10.12
Knoevenagel condensationreactions of various aldehydes and ketones with Z‐CH2‐Z′ type substrates (ethyl cyanoacetate and malononitrile) at 60 °C in mixed solvents (V2‐propanol:Vwater=2:1) demonstrated highly efficient catalytic activity. The synergistic effect between the acidic and basic sites of the Mg3Al‐PW12 composite proved to be crucial for the efficiency of the condensationreactions. Additionally
Layered double hydroxide anchored ionic liquids as amphiphilic heterogeneous catalysts for the Knoevenagel condensation reaction
作者:Tengfei Li、Wei Zhang、Wei Chen、Haralampos N. Miras、Yu-Fei Song
DOI:10.1039/c7dt03665e
日期:——
attention has been dedicated to the development of heterogeneous base catalysts providing a green and sustainable process in benign aqueous media. Herein, the ionicliquid modified layered double hydroxide (LDH) based catalysts of LDH-IL-Cn (n = 4, 8, 12) were prepared by adopting an exfoliation/assembly strategy, in which the ionicliquids (ILs) were covalently anchored onto the surface of LDH layers. The
近年来,人们一直致力于开发在良性水性介质中提供绿色和可持续工艺的非均相碱催化剂。在此,通过采用剥落/组装策略制备了LDH-IL-C n(n = 4、8、12)的离子液体改性层状双氢氧化物(LDH)基催化剂,其中离子液体(ILs)是共价的固定在LDH层的表面上。通过FT-IR,固态13 C NMR,29 Si CP / MAS NMR,27 Al-MAS NMR,XRD,TG-DTA,BET,XPS,SEM,CO 2-表征所得的LDH-IL-C n。 TPD,接触角实验等。在室温下,LDH-IL-C12在H 2 O中对各种醛与氰基乙酸乙酯/丙二腈的Knoevenagel缩合反应的催化性能显示出优异的收率和选择性。而且,LDH-IL-C12的碱催化剂可以容易地再循环和再使用至少5次,而不会降低其催化效率。放大实验表明,该催化剂保留了其效率和坚固性。