Synthesis of Chalcone and Flavanone Derivatives from Condensation of 2’-Hydroxyacetophenones and Benzaldehyde over Basic β-Zeolites

Abstract

The basic strength of alkali metal ion-exchanged β-zeolites was assessed based on the extent of Knoevenagel reaction using malonic acid derivatives and benzaldehyde. Preparation of chalcone and flavanone derivatives from the condensation of 2’-hydroxyacetophenones and benzaldehyde were carried out over the zeolites. The conversions of chalcone and flavanone derivatives and the selectivity of flavanone derivatives increased with the basic strength of the catalyst. A cyclization from chalcone to flavanone was controlled with intermolecular hydrogen bond strength of chalcone derivatives.