Monomodal vs Multimodal Microwave Irradiation Applied in the Synthesis of Fluorochalcones

The synthesis of o -, m - and p -fluorine-substituted chalcones at the ring “B” was accomplished by a Claisen-Schmidt condensation between the benzaldehyde and acetophenone. The reaction was performed in solvent-free conditions with microwave activation and good yields (> 75%) were obtained. It is noteworthy that the application of conventional reaction conditions produced very low yields and in some cases, the reaction did not proceed at all. The methodology implemented considerably reduces reaction times.