Hydrochloric Acid → 7-Bromo-4H-1-benzopyran-4-one

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Reaction Steps

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

Provenance & Evidence