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
Visible-Light Photoredox-Catalyzed Hydroalkoxymethylation of Activated Alkenes Using α-Silyl Ethers as Alkoxymethyl Radical Equivalents
作者:Nilufa Khatun、Myeong Jun Kim、Sang Kook Woo
DOI:10.1021/acs.orglett.8b02721
日期:2018.10.5
electron oxidation (SET) of α-TMS-substituted ethers, followed by subsequent conjugate addition to activated alkenes. Various functional groups were tolerated both under mild metal and metal-free conditions to provide good to excellent yields. Furthermore, the addition products were transformed to valuable synthetic building blocks, such as carboxylic acids, γ-butyrolactones, and complex aryl alkyl ethers
A new non-interpenetrating 3D metalâorganic framework [Ni4(μ6-MTB)2(μ2-H2O)4(H2O)4]·10DMF·11H2O}n (DMF = N,Nâ²-dimethylformamide) built from nickel(II) ions as connectors and methanetetrabenzoate ligands (MTB4â) as linkers has been synthesized and characterized. The single crystal X-ray diffraction showed that complex exhibits CaF2-like fluorite structure topology and four types of 3D channels with sizes about 12.6 à 9.4 à 2, 9.4 à 8.0 à 2, 12.6 à 11.7 à 2 and 14.9 à 14.9 à 2, which are filled with guest molecules. Conditions of the activation of the compound have been studied and optimized by powder X-ray diffraction during in situ heating, thermogravimetric analysis and infrared spectroscopy. Nitrogen and carbon dioxide adsorption showed that the activated sample exhibits a BET specific surface area of 700 m2 gâ1 and a carbon dioxide uptake of 12.36 wt% at 0 °C, which are the highest values reported for the compounds of the MTB4â series. The complex was tested in Knoevenagel condensation of aldehydes and active methylene compounds. Straightforward dependence of the substrate conversion on the size of used aldehyde was established. A possible mechanism of Knoevenagel condensation over a MTB4â containing a metalâorganic framework was proposed.
一种新型的非穿插三维金属有机框架[Ni4(μ6-MTB)2(μ2-H2O)4(H2O)4]·10DMF·11H2O}n(DMF=N,N'-二甲基甲酰胺)已经合成并表征。该框架由镍(II)离子作为连接器和甲烷四苯甲酸配体(MTB4-)作为连接件构建而成。单晶X射线衍射显示,该复合物表现出类似CaF2的萤石结构拓扑,并具有四种尺寸约为12.6×9.4Ų、9.4×8.0Ų、12.6×11.7Ų和14.9×14.9Ų的三维通道,这些通道中填充有客体分子。通过粉末X射线衍射、热重分析和红外光谱在原位加热过程中研究并优化了化合物的活化条件。氮气和二氧化碳吸附实验表明,活化样品的BET比表面积为700 m² g-1,在0°C时二氧化碳吸附量为12.36 wt%,这是MTB4-系列化合物中报道的最高值。该复合物在醛和活性亚甲基化合物的Knoevenagel缩合反应中进行了测试。确定了底物转化率与使用的醛大小的直接依赖关系。提出了MTB4-型金属有机框架上的Knoevenagel缩合反应的可能机制。
Synthesis of hybrid perillyl‐4
<i>H</i>
‐pyrans. Cytotoxicity evaluation against hepatocellular carcinoma
<scp>HepG2</scp>
/
<scp>C3A</scp>
cell line
作者:Ingrid M. Paczkowski、Esthéfani P. Guedes、Eduardo B. Mass、Eliana W. Meneses、Lilian A. Marques、Mário S. Mantovani、Dennis Russowsky
DOI:10.1002/jhet.3977
日期:2020.6
A series of 15 new hybrid perillyl‐4H ‐pyrans compounds was straightforwardly synthesized by a strategy combining the multicomponent reaction and the copper‐catalyzed alkyne‐azide cycloaddition (CuAAC). The 2‐amino‐4H ‐pyrans‐3‐carbonitrile containing the alkyne moiety was prepared via multicomponent reaction between 1,3‐dicarbonyl, a propargyloxy aromatic aldehyde and malononitrile or ethyl α‐cyanoacetate