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Synthesis of Substituted Stilbenes via the Knoevenagel Condensation

Author(s): Shar Saad Al-Shihry

Journal: Molecules
ISSN 1420-3049

Volume: 9;
Issue: 8;
Start page: 658;
Date: 2004;
Original page

Keywords: Knoevenagel condensation | E-stilbenes | coumarins | potassium phosphate.

Knoevenagel condensations between aldehydes and substrates containing active methylene groups were carried out in ethanol at room temperature, in the presence of potassium phosphate, to afford unsymmetrical olefins. These condensations have been shown to afford only the E-isomers in greater than 80% yields. Salicylaldehyde first produces the Knoevenagel condensation products, which undergo a subsequent heterocyclization to give coumarin derivatives. The structures of the synthesized compounds were established on the basis of UV, IR, MS and NMR spectroscopy.