Topic
Knoevenagel condensation
About: Knoevenagel condensation is a research topic. Over the lifetime, 4896 publications have been published within this topic receiving 80618 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: A review of the recent development on the catalysis by solid bases can be found in this article, where a variety of organic reactions are catalyzed in a very selective manner by base catalysts.
227 citations
TL;DR: A cationic coordination cage dramatically accelerates the Knoevenagel condensation of aromatic aldehydes in water under neutral conditions and the addition of a nucleophile to the aldehyde to generate anionic intermediates seems to be facilitated by the cationics environment of the cavity.
Abstract: A cationic coordination cage dramatically accelerates the Knoevenagel condensation of aromatic aldehydes in water under neutral conditions. The addition of a nucleophile to the aldehyde to generate anionic intermediates seems to be facilitated by the cationic environment of the cavity. The products are ejected from the cage as a result of the host–guest size discrepancy. As a result, the condensation is promoted by a catalytic amount of the cage.
220 citations
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.
219 citations
TL;DR: Depending on the aldehyde and thiol types, diverse libraries of medicinally relevant compounds can be prepared by a simple one-step process involving no chromatography.
Abstract: Heterocyclic privileged medicinal scaffolds involving pyridine, 1,4-dihydropyridine, chromeno[2,3-b]pyridine, and dihydro-1,4-dithiepine frameworks are prepared via a single-step multicomponent reaction of structurally diverse aldehydes with various thiols and malononitrile. Mechanistic studies of the synthetic pathway leading to pyridines reveal that 1,4-dihydropyridines undergo oxidation by the intermediate Knoevenagel adducts rather than by air oxygen. The use of o,o‘-disubstituted aromatic aldehydes leads to the corresponding 1,4-dihydropyridines, whereas salicylic aldehydes result in chromeno[2,3-b]pyridines. Reactions of ethanedithiol as a thiol component produce dimeric pyridines with sterically unencumbered aldehydes, while o,o‘-disubstituted aromatic aldehydes give dihydro-1,4-dithiepines. Thus, depending on the aldehyde and thiol types, diverse libraries of medicinally relevant compounds can be prepared by a simple one-step process involving no chromatography.
219 citations
TL;DR: In this article, the CsNaX-NH 2 catalyst was used for the Knoevenagel condensation reaction between benzaldehyde and ethyl 2-cyano-3 phenylacrylate.
Abstract: New basic zeolite catalysts obtained by grafting amino groups onto NaX and CsNaX zeolites exhibit excellent catalytic activities for Knoevenagel condensation reaction between benzaldehyde and ethyl cyanoacetate (ECA), ethyl acetoacetate (EAA) and diethyl malonate (DEM). The CsNaX-NH 2 catalyst also displays higher conversion compared to aminopropylated MCM-41. Knoevenagel condensation reaction in a CsNaX zeolite microreactor performed better than the traditional packed bed reactor (PBR) with an order of magnitude higher productivity (i.e. moles ethyl 2-cyano-3 phenylacrylate produced per hour for each gram catalyst). A nearly fourfold increase in reaction conversion was obtained for the microreactor when CsNaX-NH 2 catalyst was used. A membrane microreactor was obtained by incorporating a water-selective, NaA membrane to the multi-channel microreactor. The selective removal of water byproduct during the reaction led to a 25% improvement in reaction conversion for both catalysts.
205 citations