The Knoevenagel Condensation of Aromatic Aldehydes With Malononitrile or Ethyl Cyanoacetate in the Presence of Ctmab in Water

Amino group immobilized on polyacrylamide: An efficient heterogeneous catalyst for the Knoevenagel reaction in solvent-free and aqueous media

“…All products characterized by comparison of their IR and NMR spectra and physical data (m.p.) with those reported in the literature [6,21,22]. All yields refer to the isolated products.…”

“…Usually homogeneous base catalysts, such as ammonia or ammonium salts, primary and secondary amines, pyridine and piperidine are used for this reaction [3]. Heterogeneous catalysts have also been used for the Knoevenagel reaction, thus, the reaction has been catalyzed by heterogeneous catalysts based on alumina [4][5][6], silica [7], zinc and magnesium oxides [8], resins [9] and other catalysts with more or less success [10][11][12][13][14][15][16][17][18][19][20][21][22].…”

“…The Knoevenagel products are known compounds and were characterized by comparison of their physical data, IR and H 1 NMR spectra with those reported in the literature[6,21,22].…”

Visible light induced Knoevenagel condensation: A clean and efficient protocol using aqueous fruit extract of tamarindus indica as catalyst

“…In addition, Knoevenagel condensation products exhibit inhibition of antiphosphorylation of EGF-receptor and antiproliferative activity [9]. Due to their importance from a pharmacological, industrial and synthetic point of view a large number of methods for the Knoevenagel condensation have been reported using various Lewis acids/bases [10][11][12][13][14], microwave assisted reaction [15][16][17], ultrasound irradiation [18,19], biotechnology-based approach [20,21], solid phase [22,23], ionic liquid [24][25][26] or using green solvent like water [27][28][29], and grindstone method under solvent-free condition [30][31][32]. It is noteworthy to observe that all these protocols have some drawbacks, such as use of expensive catalyst, high thermal conditions, disposal of toxic solvents and catalyst, long reaction time often pose a problem.…”

Facile and Green Syntheses of 5-Arylidene-pyrimidine-2,4,6-triones and 5-Arylidene-2-thioxo-dihydro-pyrimidine-4,6-diones Using L-Tyrosine as an Efficient and Eco-Friendly Catalyst in Aqueous Medium

“…Lewis acids [11][12] , alumina 13 , Al 2 O 3 -AlPO 4 14 , zeolite 15 and ionic liquids [16][17][18][19][20] have also been added to the existing list of substances that assisted Knoevenagel condensation in organic synthesis. The use of water [21][22][23][24] as solvent, the most environmentally benign of all solvents, offers a very useful green methodology from both the economical and synthetic points of view. It not only reduces the problem of disposal of organic solvents, but also at times enhances the progress of many organic reactions.…”