环境友好催化剂壳聚糖催化Knoevenagel反应

用壳聚糖作为固相催化剂催化Knoevenagel反应,产率高,产品纯度好.壳聚糖无毒无害且能被微生物降解,对环境友好,是绿色催化剂.     

室温水介质中氟化钾催化的Knoevenagel反应

以氟化钾作为催化剂,在室温水介质中促进芳香醛与活泼亚甲基化合物发生Knoevenagel缩合反应,其反应时间短,条件温和,产率高,产品纯度好,操作和后处理简单,催化剂可重复使用多次.     

碱性氧化铝催化芳醛与丙二腈的Knoevenagel缩合反应

无溶剂下,以碱性氧化铝为催化剂催化芳醛和丙二腈的Knoevenagel缩合反应,合成了一系列的芳基亚甲基丙二腈化合物。实验结果表明,该法具有操作和后处理简单、产率高、催化剂能够循环使用、对环境友好等优点,符合绿色化学的要求。     

新型酸性离子液体催化的 Knoevenagel缩合反应

研究了一类新型酸性离子液体催化的Knoevenagel缩合反应, 结果表明, 该催化剂适用于一系列芳香/杂环醛与α-取代活性亚甲基化合物间的反应, 反应可在室温下进行, 反应时间短且收率良好(92% ~98%). 该反应体系操作简单, 产物易分离. 提出了可能的反应机理并对机理进行了验证. 该离子液体重复使用5次后仍具有较高的反应活性.     

Knoevenagel Condensation Catalyzed by Sodium Silicate Under Solvent-Free Conditions

Abstract

Sodium silicate pentahydrate has been utilized as an efficient catalyst for the Knoevenagel condensation of aromatic aldehydes with active methylene compounds to afford substituted olefins in yields of 80.6%～98.9% under solvent-free conditions at room temperature within a short time. The advantages of this procedure are mild reaction conditions, excellent yields, cleaner reaction profiles, and operational simplicity.

GRAPHICAL ABSTRACT      

碱性功能化离子液体催化knoevenagel缩合反应

碱性功能化离子液体;催化;knoevenagel缩合反应;丙二氰;氰基乙酸乙酯     

脯氨酸离子液体催化Knoevenagel缩合反应(英文)

改进了1-丁基-3-甲基咪唑L-脯氨酸([bmim][Pro])功能化离子液体的合成路线,并将该离子液体用于催化含活泼亚甲基化合物与醛或酮的Knoevenagel缩合反应.在水介质中,室温下,该离子液体可快速催化上述Knoevenagel缩合反应,并选择性生成α,β-不饱和羰基化合物且分离收率可达到88%～97%.该脯氨酸离子液体循环重复使用6次后,催化活性没有明显的下降.此外,初步探讨了其催化过程机理.     

KF／Al2O3催化下的Knoevenagel缩合反应

ＫＦ／Ａｌ＿２Ｏ＿３催化下的Ｋｎｏｅｖｅｎａｇｅｌ缩合反应戴桂元，史达清，周龙虎（徐州师范学院化学系徐州２２１００９）关键词Ｋｎｏｅｖｅｎａｇｅｌ缩合反应，氟化钾／氧化铝，芳香醛，氰乙酸乙酯，氰乙酰胺Ｋｎｏｅｖｅｎａｇｅｌ缩合反应一般在碱催化下进行，...     

室温无溶剂条件下醋酸锌催化的Knoevenagel缩合反应

以醋酸锌作为催化剂, 在室温无溶剂条件下催化芳香醛与活泼亚甲基化合物发生Knoevenagel缩合反应, 其反应条件温和, 产率最高可达100%, 产品纯度好, 操作和后处理简单.     

Amine functionalized MCM-41: An active and reusable catalyst for Knoevenagel condensation reaction

This paper reports preparation, characterization of amine modified mesoporous crystalline MCM-41 and its application in Knoevenagel condensation reaction. Amine modified MCM-41 was prepared by co-condensation and post-synthesis methods. The samples were characterized by X-ray powder diffraction, Fourier-transfer infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron micrograph (SEM), ²⁹Si magic-angle spinning (MAS), nuclear magnetic resonance (NMR), diffuse reflectance spectra (DRS), nitrogen adsorption–desorption and CHN analysis. X-ray diffraction patterns indicate that the modified materials retain the standard MCM-41 structure. SEM study exhibits that the arrangement of particles for 12.8% amine modified MCM-41 is well ordered and spherical in nature. CHN analysis supports that complete hydrolysis of ethoxy groups take place in 12.8% amine modified sample. From the NMR study it is confirmed that the surface coverage is 40% in 12.8% amine modified sample. The base catalytic activity of hybrid MCM-41 materials such as amine (post-synthesis and co-condensation methods) and surfactant functionalized materials for condensation reaction between benzaldehyde and diethyl malonate in solvent free, room temperature synthesis of cinnamic acid was evaluated and correlated with the surface and textural properties. Sample containing 12.8 wt% amine loaded by co-condensation method showed highest malonic ester conversion (92%) and selectivity (98%) for cinnamic acid.     

Leucoemeraldine-Base-Catalyzed Knoevenagel Condensation

A facile method for Knoevenagel condensation has been developed by using Leucoemeraldine base as catalyst to give substituted alkenes in excellent yields. The recycling of the solid catalyst was investigated.     

Knoevenagel Condensation of Acetylacetone with AldehydesCatalyzed by a New Catalyst Indium Trichloride

Duringthepastdecade,considerableattentionhasbeenfocusedontheorganoindiumchemistry.'AhandfulofpaPersontheaPplicationofallylindinmreagefltsandindinmpowdermediatedorganicreactionwerereported.'Mostrecelltly,indiumtfichloridehasbeenusedinorganicsynthesis.ForexamPle,InCl3-Me3SiClsystemhasbeenusedtopromotetheMukaiyamaaldolreaction,'Whiletheadditionofallylicstannanestoalde-hydespromotedbyInCl3hasalsobeenreported.'ItwasindicatedthatasanewLewisacidpromoter,InCl3mayreplacetheotherLewisacidssuchasB…     

3—N,N—二甲基—1,3—丙二胺／冰醋酸催化下的Knoevenagel缩合反应

对硝基苯磺酰基乙腈与芳香醛在３－Ｎ，Ｎ－二甲基－１，３－丙二胺（ＤＰＡ）／冰醋酸催化下可顺利地发生Ｋｎｏｅｖｅｎａｇｅｌ缩合反应，生成２－（４－硝基苯磺酰基肉桂腈类化合物，产率８３％～９８％。但与水杨醛反应生成的产物是六元环丙酯，其结构经元素分析，ＩＲ，ＨＮＭＲ和ＭＳ确证。     

3－N，N－二甲基－1，3－丙二胺／冰醋酸催化下的Knoevenagel缩合反应

对硝基苯磺酰基乙腈与芳香醛在３－Ｎ，Ｎ－二甲基－１，３－丙二胺（ＤＰＡ）／冰醋酸催化下可顺利地发生Ｋｎｏｅｖｅｎａｇｅｌ缩合反应，生成２－（４－硝基苯磺酰基肉桂腈类化合物，产率８３％～９８％。但与水杨醛反应生成的产物是六元环内酯，其结构经元素分析、ＩＲ、￣１ＨＮＭＲ和ＭＳ确证。     

离子液体功能化二氧化硅催化Knoevenagel反应

在100 ℃, 无外加溶剂条件下, 离子液体功能化二氧化硅催化一系列芳醛和活泼亚甲基化合物进行Knoevenagel 缩合反应, 以高产率生成相应产物. 当反应底物为水杨醛与氰基乙酸乙酯的时候, 产物为3-乙氧基羰基香豆素, 这是水杨醛和氰基乙酸乙酯缩合关环, 再发生氰基醇解的产物. 采用离子液体功能化二氧化硅作为反应催化剂, 反应后催化剂可回收再利用.     

Ionic liquid-functional MCM-41 as a high effective catalyst for the synthesis of isatylidene malononitrile via Knoevenagel condensation

Ionic liquid functional MCM-41 was synthesized, characterized and used as heterogeneous catalyst for the Knoevenagel condensation of isatins with malononitrile. A series of corresponding isatylidene malononitrile were obtained in high isolated yield (96–99%) at room temperature in a short time. The heterogeneous catalyst can be easily recovered by centrifugation and showed almost no loss of activity over 10 recycle experiments. At the same time, the gram-scale experiments showed excellent yields and provided a highly effective method for scale up applications.     

Knoevenagel Condensation Catalysed by Alumina

在Ａｌ２Ｏ３催化下活泼亚甲基化合物和羰基化合物进行克脑文格尔缩合反应，在温和的反应条件下得到较高收率的产物。将超声波辐射应用于该缩合反应使反应速度明显提高。     

尿素催化的高效绿色Knoevenagel缩合反应

An efficient and green procedure for the urea catalyzed Knoevenagel condensation was developed. In the presence of a catalytic ammount of urea, stoichiometric aldehyde and active methylene compound reacted under sol-vent-free conditions at 100℃ for 5-60 min to give nearly quantitative yield of product.     

Basic Ionic Liquid： A Reusable Catalyst for Knoevenagel Condensation in Aqueous Media

IntroductionThe Knoevenagel condensation of aldehydes/ketones and activated methylene compounds is one ofthe most common synthetic methods to produce func-tionalized alkenes. Theα,β-unsaturated productsobtained by this method have been widely used as th…     

Simple,Efficient, and Green Procedure for the Knoevenagel Condensation Catalyzed by Ethylenediammonium Diacetate Under Solvent-Free Conditions

A simple, efficient, and green procedure for Knoevenagel condensation of aromatic aldehydes with malononitrile and ethyl cyanoacetate catalyzed by ethylenediammonium diacetate under solvent-free conditions at room temperature is reported. This method gives remarkable advantages such as a simple procedure, mild conditions, fast (1–45 min) reactions, and excellent yields. Additionally, the catalyst can be reused for at least five runs without significant decrease of the yields.