Highly active g-C<sub>3</sub>N<sub>4</sub> as a solid base catalyst for knoevenagel condensation reaction under phase transfer conditions
作者:Priti Sharma、Yoel Sasson
DOI:10.1039/c7ra03051g
日期:——
promising approach, heterogeneous g-C3N4 as a solid base catalyst exhibits appreciable activity in Knoevenagel condensations at room temperature for the synthesis of substituted stilbene in presence of a crown-ether phasetransfer catalyst. High yield of the product substituted stilbene were isolated in a very short reaction time period (∼30 min). The solid base g-C3N4 catalyst was proven to be recyclable
在一种有前途的方法中,作为固体碱催化剂的多相gC 3 N 4在室温下的Knoevenagel缩合中显示出明显的活性,用于在冠醚相转移催化剂存在下合成取代的苯乙烯。在很短的反应时间(约30分钟)内分离出高产率的取代苯乙烯的产物。固态碱gC 3 N 4催化剂经证实可循环使用多次。使用多相碱式gC 3 N 4催化剂筛选了各种芳族底物,在室温下显示出可观的相应产物收率(〜99%)。
Fluorescence Regulation and Photoresponsivity in AIEE Supramolecular Gels Based on a Cyanostilbene Modified Benzene‐1,3,5‐Tricarboxamide Derivative
π–π interactions, further resulting in disparate packing modes of gelators. In addition, only the G‐gel displays gel‐to‐soltransition accompanied with fluorescence switching according to the trans‐cis photoisomerization of cyanostilbene under UV light irradiation. The B‐gel does not exhibit any change because of its tight hexagonal packing arrangement. Such packing modes restricted the space in which
synthesising symmetrical and non-symmetrical 3,4-diaryl-substituted pyrroles is proposed, consisting of (i) the condensationreaction between phenylacetonitriles and aldehydes to give acrylonitriles, (ii) the conjugate addition of cyanide to afford succinonitriles, and (iii) reduction of the succinonitriles with DIBAL-H to provide the target pyrroles in good overall yields. The implementation of this technology
提出了一种合成对称和非对称 3,4-二芳基取代吡咯的简单方法,包括 (i) 苯乙腈和醛之间的缩合反应得到丙烯腈,(ii) 氰化物的共轭加成得到丁二腈,和(iii) 用 DIBAL-H 还原丁二腈,以良好的总产率提供目标吡咯。介绍了该技术用于制备层状蛋白 R 的实施。
Application of group V polyoxometalate as an efficient base catalyst: a case study of decaniobate clusters
We demonstrated for the first time that [Nb10O28]6− exhibited base catalytic activity for aldol-type condensation reactions including Knoevenagel and Claisen–Schmidt condensation reactions.
Kinetics and mechanism of the addition of benzylamines to β-nitrostilbenes and β-cyano-4′-nitrostilbenes
作者:Hyuck Keun Oh、Tae Soo Kim、Hai Whang Lee、Ikchoon Lee
DOI:10.1039/b108021k
日期:2002.1.23
addition in acetonitrile is the direct resonance effect (σ− or R−) while that in aqueous solution is the polar electron-withdrawing effect (σ) of the activating groups. Due to stericinhibition the β-phenyl rings in NSB and CNS are prevented from π-overlap with the anionic center in the TS so that the reduced resonance effect leads to unduly low addition rates. The kinetic isotope effects and activation