Epoxidation of chromones and flavonoids in ionic liquids

A convenient and efficient procedure for the epoxidation of chromone, isoflavone, and chalcone derivatives using 1-butyl-3-methyl imidazolium tetrafluoroborate [bmim]BF4 as solvent and alkaline hydrogen peroxide as oxidant is described. All reactions proceed in good yields and faster than in conventional solvents. No evidence of formation of compounds derived from the opening of the epoxide ring was attained.