Alkylacylimidazoles in Claisen–Schmidt and Knoevenagel Condensations

Alkylacylimidazoles were shown to be good reagents for Claisen–Schmidt and Knoevenagel-like condensations. The Claisen–Schmidt condensation of N-acetylimidazole with benzaldehyde followed by acidification with HCl gave cinnamic acid. The Knoevenagel-like condensation of N-(acetoacetyl)imidazole with hydrated aldehydes resulted in a fast and efficient formation of β-hydroxyketones. The studied reactions provide a new and general synthetic approach to cinnamic acid derivatives and β-hydroxyketones, as well as a new application field of alkylacylimidazoles.