DABCO离子液体催化Knoevenagel缩合反应

以三乙烯二胺(DABCO)为原料,通过两步法制备了离子液体[DABCO-PDO][PF6];将其用于催化芳香醛与多种活性亚甲基化合物(丙二腈,氰基乙酸乙酯,苯并噻唑乙腈,苯乙腈)的Knoevenagel缩合反应;讨论了可能的反应机理,并基于催化剂的双重催化作用阐述了反应的高效性.结果表明,该反应体系无需任何溶剂,在室温(25℃)下就能进行,催化剂用量小,反应时间短,收率高,反应后处理简单,反应普适性较高;且催化剂重复使用5次后仍保持很高的催化活性.     

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.     

锌-脯氨酸复合物催化的水相Knoevenagel缩合

报道了锌-脯氨酸复合物催化下的水相Knoevenagel缩合反应.17种芳香醛以及2种脂肪环酮与丙二腈在80℃下反应5～10 min,能够以84%～99%的收率得到相应的Knoevenagel缩合产物.催化剂回收重复使用10次,其催化活性不受影响.     

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.     

Al2O3催化克脑文格尔缩合反应

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量提高。     

TeCl4催化合成α,β—不饱和羰基化合物

用ＴｅＣｌ４催化含有活泼亚甲基的羰基化合物与醛的Ｋｎｏｅｖｅｎａｇｅｌ反应，合成了一系列α，β－不饱和酮或酯，收率最高达９５％。     

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。     

三碘化钐催化的一锅法合成α-胺基腈化合物

在三碘化钐催化下,羰基化合物(醛、酮)、胺(伯胺、仲胺)和三甲基氰硅烷(TMSCN)能进行Strecker反应,以良好的收率得到相应的α-氰基化合物.在该反应条件下,底物中的官能团(硝基、碳碳双键和卤素等)不受影响.     

丙二腈及氰乙酸酯参与的3-脱氢莽草酸甲酯缩合-芳构化-环合串联反应

3-脱氢莽草酸甲酯与丙二腈、氰乙酸乙酯及氰乙酸甲酯等活性亚甲基化合物在一定条件下发生缩合、芳构化及环合反应,可方便地构建C—C键并得到多取代的2-氨基苯并呋喃类化合物(3a~3e,4a和4b),其中化合物3a中的氰基和甲氧羰基可分别进行选择性水解.该方法具有原料易得、条件温和、操作简单及收率高等优点,为可再生生物质资源莽草酸的多样化转化和利用提供了新思路.     

ZnCl2温和有效地催化活泼亚甲基化合物与苄醇或烯丙醇的 直接烷基化反应

报道了ZnCl2催化的活泼亚甲基化合物和苄醇或烯丙醇的直接烷基化反应. 在无水ZnCl2 (5～10 mol%)的催化下, 以二氯甲烷为溶剂, 活泼亚甲基化合物和苄醇或烯丙醇进行直接烷基化反应以较高的收率得到活泼亚甲基化合物的烷基化产物, 反应后处理简单, 说明ZnCl2是一种温和有效的活泼亚甲基化合物和苄醇或烯丙醇进行直接烷基化的催化剂. 并对反应的机理进行了初步研究.     

A Simple,Efficient and Green Procedure for the Knoevenagel Condensation of Aldehydes with N-Methylpiperazine at Room Temperature under Solvent-Free Conditions

Knoevenagel condensation 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 under solvent-free conditions in the presence of N-methylpiperazine in excellent yields of the E-configured products.     

The Condensation of Aromatic Aldehydes with Acidic Methylene Compounds in Water

The condensation of aromatic aldehydes with acidic methylene compounds such as malononitrile, methyl cyanoacetate, cyanoacetamide, 5,5-dimethyl-1,3-cyclohexanedione,bartbituric acid and 2-thiobarbituric acid proceeded very efficiently in water in the presence of triethylbenzylammonium chloride (TEBA) and the products were isolated simply by filtration.     

喹啉类离子化合物的合成及其室温促进下Knoevenagel反应的研究

以喹啉为原料, 在温和条件下制得喹啉类离子化合物1～9, 并在室温下将其用于Knoevenagel缩合反应, 以80%～95%的收率高效生成相应的烯腈a～f, 离子化合物经过简单处理即可重复使用.     

A simple, efficient, and green protocol for Knoevenagel condensation in a cost-effective ionic liquid 2-hydroxyethlammonium formate without a catalyst

Knoevenagel condensation of aromatic aldehydes with active methylene compounds such as malononitrile, ethylcyanoacetate, and cyanoacetamide proceeded very smoothly in reusable and cheap ionic liquid 2-hydroxyethylammonium formate at room temperature in the absence of a catalyst. Compared to other reported ionic liquids, the ionic liquid 2-hydroxyethylammonium formate shows better potential in the applications on the industrial scale with its low cost and viscosity.     

水相中磷酸氢二铵催化Knoevenagel反应

醛与活泼亚甲基化合物的Knoevenagel反应是有机合成中广泛应用的形成碳碳键的重要方法,该反应一般是弱碱性催化剂存在下完成的,如各类胺、脲[1]等,Lerwis酸[2]、杂多酸[3]、氨基酸[4]等也可用于催化该反应。近年来,无溶剂条件下超声、微波辅射[5-6]也可以促进反应,但大部分是在     

Sodium Benzoate as a Green,Efficient, and Recyclable Catalyst for Knoevenagel Condensation

Sodium benzoate was utilized as a novel efficient and green catalyst for the Knoevenagel condensation of aldehydes with active methylene compounds such as ethyl cyanoacetate and malononitrile to afford substituted olefins through the conventional stirring or under ultrasounic irradiation. Improvements were observed by carrying out the reactions under ultrasound irradiation. The reaction proceeded smoothly under mild conditions at room temperature, and the products were obtained in excellent yields within short times: The catalyst remains active and exhibits no substantial loss of activity for up to four reaction cycles.     

Novel,Efficient, and Green Procedure for the Knoevenagel Condensation Catalyzed by Diammonium Hydrogen Phosphate in Water

Knoevenagel condensation of various aromatic and heteroaromatic aldehydes with active methylene compounds like methyl and ethyl cyanoacetate, malononitrile, and cyanoacetamide proceeds smoothly with stirring in water in the presence of 4 mol% of diammonium hydrogen phosphate. The reactions were carried out at room temperature in short periods with very simple workup procedure and good to high yields.     

Nano‐Fe3O4 Encapsulated‐Silica Particles Bearing 3‐Aminopropyl Group as a Magnetically Separable Catalyst for Efficient Knoevenagel Condensation of Aromatic Aldehydes with Active Methylene Compounds

Knoevenagel condensation of aromatic aldehydes with active methylene compounds such as malononitrile, ethylcyanoacetate, benzimidazol‐2‐acetonitrile and benzothiazole‐2‐acetonitrile proceeded very smoothly, catalyzed by nano‐Fe₃O₄ encapsulated‐silica particles supported primary amine. Both reaction time and yield are satisfying. The advantages of this catalyst are ease of preparation, non‐toxicity, low cost, ease of handling and recyclability.     

Uncatalysed Knoevenagel condensation in aqueous medium at room temperature

Knoevenagel condensation of various aromatic and heteroaromatic aldehydes with active methylene compounds like malononitrile, ethyl cyanoacetamide, ethyl cyanoacetate, barbituric acids, Meldrum’s acid, dimedone and pyrazolone proceeds smoothly with stirring in an aqueous medium. The reactions occur at room temperature giving excellent yields of the products. The work-up procedure is very simple and the products do not require further purification.