An efficient solvent free Amberlite IRA-400 Cl resin mediated multicomponent synthesis and photophysical properties of fluorescent 4 H -chromene derivatives
An efficient Amberlite IRA-400 Cl basic anion exchange resin mediated multicomponent reaction of 2-hydroxybenzaldehydes, 1, 3-diketone and nucleophiles under neat condition afforded a number of fluorescent 4H-chromenederivatives in excellent yield. The structure of the synthesized compounds 4k and 4u were confirmed from single crystal XRD studies. 4H-Among the chromene derivatives, compound 4v synthesized
New insight into experimental and theoretical mechanistic study on a green synthesis of functionalized 4
<i>H</i>
‐chromenes using magnetic nanoparticle catalyst
A greensynthesis of functionalized 4H‐chromenes using one‐pot, three‐component reaction of salicylaldehyde (1), active methylene (2), and carbon‐based nucleophile (3) using Fe3O4@CONa nanoparticles in water has been performed at 60°C. The Fe3O4@CONa nanoparticle as an efficient, green, and magnetically reusable heterogeneous catalyst was applied in these reactions up to the nine runs. Green catalyst
使用Fe 3 O 4 @CONa纳米粒子在水中通过水杨醛(1),活性亚甲基(2)和碳基亲核试剂(3)的一锅,三组分反应进行绿色合成功能化4 H-色烯。在60°C下进行。铁3 O 4作为一种有效,绿色和可磁重复使用的多相催化剂,CONa纳米颗粒被用于这些反应中,直到九次运行。发现绿色催化剂和溶剂,较短的反应时间,较高的产品收率以及简单的后处理程序是该方法的一些优点。密度泛函理论计算应用于一锅,三组分反应机理的全包感知。最多的反应是通过以下途径进行的:(a)2比1的亲核加成;(b)闭环,脱水;(c)3(2-萘酚,4-羟基香豆素)亲核取代为中间体。有时将机制突变为:(a)将3(吲哚,2-甲基吲哚)亲核加成1,脱水;(b)将2亲核加成;(c)闭环和脱水。前沿的分子轨道,NBO分析,反应物的分子静电势和中间体证实了该提议机制。理论研究可能有助于挑选合适的反应物。
Nanocrystalline and Reusable ZnO Catalyst for the Assembly of Densely Functionalized 4<i>H</i>-Chromenes in Aqueous Medium via One-Pot Three Component Reactions: A Greener “NOSE” Approach
作者:Partha Pratim Ghosh、Asish R. Das
DOI:10.1021/jo400763z
日期:2013.6.21
An ecofriendly, One-pot, three component ZnO nanoparticles-mediated synthesis of 4H-chromene in water under thermal condition has been described. The highly product-selective three component electrophilic reaction of 2-hydroxybenzaldehyde with an active methylene compound and another carbon-based varied nature of nucleophile has been developed by a reversible alkylation procedure using greener "NOSE" approach. Greenness of the process was well instituted, as water was used both;as reaction media as well as medium for the synthesis of catalyst. In these reactions, the use of nano-ZnO as a catalyst was documented to be crucial for rendering the reactions possible in water media, while replacing nano-ZnO with other acids or bases resulted in the generation of too many side products. The catalyst can be efficiently recycled up to the sixth run, an essential point in the area of green chemistry. The methodology provides cleaner conversion, shorter reaction times, and high selectivity, which make the protocol globally putative. The crystal structures of 4H-chromene, easily produced by a chromatography-free highly product-selective reaction, were explored by means of single crystal X-ray diffraction analysis, and H-bonding arrangements of one signified compound prepared is presented. In optimized mild conditions, the isolated yields are 86-93%.
Application of potassium-modified carbon nitride as a highly efficient recyclable catalyst for synthesis of 4H-chromene derivatives
electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The obtained K-CN exhibited excellent catalytic activity for synthesis of 4 H -chromene derivatives via one-pot three-component reaction of salicylaldehyde, cyclohexane-1,3-diones and 4-hydroxycoumarin in water/ethyl lactate at room temperature. The reported method shows significant