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Journal ArticleDOI

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

18 Aug 2008-Synthetic Communications (Taylor & Francis Group)-Vol. 38, Iss: 13, pp 2103-2112
Abstract: 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.
Topics: Knoevenagel condensation (65%), Malononitrile (63%), Cyanoacetamide (50%)
Citations
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Journal ArticleDOI
01 Aug 2012-Green Chemistry
Abstract: A series of new fiber catalysts has been synthesized by aminating a commercially available polyacrylonitrile fiber with polyamines such as diethylenetriamine and triethylenetetramine. These fiber catalysts can efficiently catalyze the Knoevenagel condensation of benzaldehyde and ethyl cyanoacetate in water (yields: 95–98%). The triethylenetetramine aminated fiber catalyst was used to catalyze the condensations of a wide range of aromatic aldehydes and active methylene compounds and in each case, this catalyst performed well with yields higher than 93%. This fiber catalyst also exhibited excellent reusability (up to 21 times) and photostability.

87 citations


Journal ArticleDOI
01 Jul 2013-RSC Advances
Abstract: An efficient and reusable protic-ionic-liquid solvent–catalyst system, HMTA–AcOH–H2O, has been developed and used in the Knoevenagel condensation reaction of aromatic aldehydes with ethyl 2-cyanoacetate. Under ultrasonic irradiation, the Knoevenagel condensation promoted by the protic-ionic-liquid solvent–catalyst system proceeds smoothly and cleanly. Moreover, the HMTA–AcOH–H2O solvent–catalyst system could be recycled for at least 6 times and no significant loss of activity was observed. This protocol has notable advantages, such as being eco-friendly, the ease of the work-up and reuse of the ionic liquid conveniently, which could help reduce disposal costs and contribute to the development of new catalysts for use in green and continuous chemical processes.

48 citations


Journal ArticleDOI
Anguo Ying1, Li-Min Wang, Le-Le Wang, Xinzhi Chen1, Wei-Dong Ye 
Abstract: An efficient, clean and facile protocol for the Knoevenagel condensation of aromatic aldehydes with active methylene compounds catalysed by task specific ionic liquid 1,8-diazabicyclo[5.4.0]-undec-...

32 citations


Journal ArticleDOI
Abstract: To use as the efficient solid base catalysts, alanine functionalized MCM-41 (Alanine-MCM-41), catalysts viz. 16Alanine-MCM-41 and 8Alanine-MCM-41, were successfully prepared by post-grafting method using MCM-41 synthesized by basic sol-gel method. The synthesized Alanine-MCM-41 catalysts were characterized by several instrumental techniques such as XRD, N2-sorptions and TEM to confirm the standard mesoporous nature. The CHN result shows that the alanine groups have been successfully functionalized on the surface of MCM-41 while the functionalization of alanine groups on MCM-41 were also confirmed by FTIR spectra. The total basic sites of 16Alanine-MCM-41 determined by TPD-CO2 are higher than that of 8Alanine-MCM-41 and enhance to lead the Knoevenagel condensation of furfural and acetylacetone under solvent-free condition. A variety of reaction parameters such as reaction time, temperature, mole ratio and solvents were studied to find an optimum parameter. The Alanine MCM-41 catalysts were successively recovered and reused several times without loss of catalytic activity because of strongly anchored the alanine groups on inner pore of MCM-41, as confirmed by FTIR spectra. Compared to 8Alanine-MCM-41, the 16alanine-MCM-41 gives higher catalytic activity in this reaction because its total base sites lead to produce a major product, 3-(2-furylmethylene)-2,4-pentanedione (FMP) with 100% selectivity using the best parameters like 1:1 M ratio of furfural: acetylacetone, 100 °C and 30 min.

26 citations


Journal ArticleDOI
Abstract: A new silica based piperidine derivative has been designed, synthesized and characterized by solid state carbon 13 CP MAS NMR, BET surface area analysis, IR, TGA studies, elemental analysis and pH experiment. This has been efficiently utilized as a recyclable catalyst for both homo and hetero bis-Knoevenagel condensation products in aqueous-ethanol. This is the first report of the synthesis of hetero bis-Knoevenagel condensation products by our designed catalyst.

26 citations


References
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Journal ArticleDOI
16 May 2000-ChemInform
TL;DR: This paper presents a new approach to solvent-free organic synthesis called “Solvent-free synthesis with real-time stoichiometry” that combines high-performance liquid chromatography and high-tech electronics.
Abstract: Solvent-free organic synthesis , Solvent-free organic synthesis , کتابخانه دیجیتال جندی شاپور اهواز

940 citations


Book
01 Jan 2003-
Abstract: Solvent-free organic synthesis , Solvent-free organic synthesis , کتابخانه دیجیتال جندی شاپور اهواز

805 citations



Journal ArticleDOI
Abstract: The knoevenagel condensation of carbonyl substrates with acidic methylene reagents proceeds smoothly in presence of zinc chloride, without the need for solvent, to produce products of good purity in high yield.

252 citations


Journal Article
Abstract: The basic ionic liquid 1-butyl-3-methylimidazolium hydroxide, [bmIm]OH, efficiently catalyzes Knoevenagel condensation without requirement of any organic solvent. A wide range of aliphatic and aromatic aldehydes and ketones easily undergo condensations with diethyl malonate, malononitrile, ethyl cyanoacetate, malonic acid and ethyl acetoacetate. The reactions proceed at room temperature and are very fast (10-30 min). However, the most significant feature of this methodology is the condensation of aliphatic aldehyde with diethyl malonate, which is not very easy to achieve by conventional reagents, and was not addressed adequately in literature providing a general and convenient procedure.

201 citations