91138-32-8Relevant academic research and scientific papers
Cascade Synthesis of 2-Cyanoacrylamides through Deacetalization and/or Knoevenagel Condensation followed by Selective Monohydration of Acetals and Aldehydes over Solid Acid Ferrites
Kamble, Sumit B.,Rode, Chandrashekhar V.
, p. 2678 - 2687 (2016/08/30)
A new protocol of cascade synthesis for biologically active 2-cyanoacrylamides (1) was developed. The reaction proceeds over a novel magnetically retrievable solid-acid composite of iron oxide, poly(vinylpyrrolidone) and phosphotungstic acid (Fe3O4/PVP–PWA) in AcOH–H2O medium under reflux conditions. This transformation is facilitated through single-site Br?nsted acid catalyzed cascade reactions involving deacetalization and/or Knoevenagel condensation followed by selective monohydration of nitriles starting from acetals (5) and aldehydes (2) with malononitrile (3). A series of aldehydes, dimethyl and diethyl acetals, along with some heterocyclic aldehydes were successfully transformed to 2-cyanoacrylamides with >95 % yields. TEM images confirmed the coating of the PVP over nanosized Fe3O4. Stereoselective monohydration of 2-benzylidenemalononitriles (4) to E isomers was demonstrated by NOESY experiments. The catalyst could be efficiently recycled seven times on employment of both acetals and aldehydes as substrates, as a result of its magnetic nature.
Rare-earth (RE) exchanged NaY zeolite promoted Knoevenagel condensation
Reddy, T. Indrasena,Varma, Rajender S.
, p. 1721 - 1724 (2007/10/03)
Knoevenagel condensation is assisted by rare-earth exchanged NaY zeolites wherein various functionalized arylaldehydes react readily with active methylene compounds to produce corresponding olefinic products.
