Solvent-Free Microwave Enhanced Knoevenagel Condensation of Ethyl Cyanoacetate with Aldehydes
TL;DR: In this article, a high yielding and fast method of Knoevenagel condensation of ethyl cyanoacetate with various aldehydes under microwave irradiation using environment-friendly ammonium acetate in the absence of any solvent is described.
Abstract: A high yielding and fast method of Knoevenagel condensation of ethyl cyanoacetate with various aldehydes under microwave irradiation using environment-friendly ammonium acetate in the absence of any solvent is described.
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TL;DR: A series of new fiber catalysts has been synthesized by aminating a commercially available polyacrylonitrile fiber with polyamines such as diethylenetriamine and triethylenetetramine as discussed by the authors.
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.
114 citations
TL;DR: When milled together with calcite or fluorite, malononitrile and methyl cyanoacetate readily underwent Knovenagel condensation with aromatic aldehydes, giving the corresponding arylidenemalononitriles and (E)-α-cyanocinnamic esters in good yield as mentioned in this paper.
Abstract: When milled together with calcite or fluorite, malononitrile and methyl cyanoacetate readily underwent Knovenagel condensation with aromatic aldehydes, giving the corresponding arylidenemalononitriles and (E)-α-cyanocinnamic esters in good to excellent yield.
100 citations
TL;DR: In this paper, a new fiber catalyst for Knoevenagel condensation has been prepared by aminating a commercially available polyacrylonitrile fiber with N,N-dimethyl-1,3-propanediamine.
Abstract: A new fiber catalyst for Knoevenagel condensation has been prepared by aminating a commercially available polyacrylonitrile fiber with N,N-dimethyl-1,3-propanediamine. The fiber catalyst was characterized by elemental analysis, X-ray powder diffraction spectra (XRD), scanning electron microscopy (SEM) and Fourier-transfer infrared spectroscopy (FTIR). The Knoevenagel condensation proceeded smoothly in the presence of the fiber catalyst and the products were obtained in excellent yields. This catalyst is applicable to a wide range of aromatic aldehydes. Moreover, the reaction can be easily carried out in different solvents of varying polarities. The newly developed fiber catalyst was also found to exhibit excellent recyclability and reusability (up to 10 times) without any additional treatment.
93 citations
TL;DR: In this article, the synthesis, characterization and applications of guanidine supported on magnetic nanoparticles Fe 3 O 4 (MNPs-Guanidine) as a novel magnetically separable base nanocatalyst are described.
Abstract: The synthesis, characterization and applications of guanidine supported on magnetic nanoparticles Fe 3 O 4 (MNPs–Guanidine) as a novel magnetically separable base nanocatalyst are described. We have studied the application of this new catalyst for the Knoevenagel condensation reaction of aromatic aldehydes with malononitrile or cyanoacetate in PEG/water = 1:1 at room temperature. Also, the three-component and one-pot synthesis of 2-amino-4 H -chromenes and 2-amino-4 H -benzo[ h ]chromenes by condensing aldehydes, malononitrile and cyclic 1,3-dicarbonyl/α-naphthol, in the presence of catalytic amount of MNPs–Guanidine under same conditions is investigated. The supported catalyst could simply be separated and recovered from the reaction mixture with the assistance of an external magnet and reused several times.
81 citations
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TL;DR: The Knoevenagel condensation of carbonyl compounds with active methylene compounds was readily carried out with aluminium oxide as a catalyst as discussed by the authors, and was shown to work well in the presence of active methylenes.
Abstract: The Knoevenagel condensation of carbonyl compounds with active methylene compounds was readily carried out with aluminium oxide as catalyst.
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