Accessing Highly-Halogenated Flavanones Using Protic Ionic Liquids and Microwave Irradiation

A series of highly-functionalized 2-hydroxychalcones have been synthesized using a microwave-assisted Claisen-Schmidt condensation. Conversion of these 2-hydroxychalcones to their corresponding flavanones was then performed utilizing protic ionic liquids (pIL) and microwave irradiation. This methodology drastically reduces reaction time to 15 minutes compared to typical thermal methods (24 hrs) and is tolerant to a broad range of functional groups. Several chalcones reported bear four and five substituents - a degree of substitution rarely reported in the literature. Keywords: Chalcone, Claisen-Schmidt, Flavanone, Hydroxyacetophenone, Microwave, Protic Ionic Liquid, Microwave-assisted chalcone, Protic ionic liquids, chalcone synthesis, Thin layer chromatography (TLC), Column Chromatography, Protic ionic liquids (pILs), EAN (ethylamine:nitric acid), TeaMs (triethylamine:methanesulfonic acid), proton activity