945724-02-7

168759-60-2

General procedure for the synthesis of 7-bromo-4H-chromen-4-one from (E)-1-(4-bromo-2-hydroxyphenyl)-3-(dimethylamino)prop-2-en-1-one: Concentrated hydrochloric acid (30 mL) was slowly added to a (E)-1-(4-bromo-2-hydroxyphenyl)-3-(dimethylamino)prop-2-en-1-one (10.4 g, 38.5 mmol) in a solution of dichloromethane (250 mL). The reaction mixture was heated to reflux for 30 minutes and then cooled to room temperature. The aqueous phase was extracted with dichloromethane (20 mL). The organic phases were combined, washed with saturated sodium bicarbonate solution (50 mL), dried over anhydrous sodium sulfate, and filtered. The solvent was removed by concentration under reduced pressure to give 7-bromo-4H-chromen-4-one (8.7 g, 38.5 mmol, 100% yield).