Acetone → 6-bromo-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-4-one

Participants

Reaction Steps

A solution of 1-(5-bromo-2-hydroxy-phenyl)-ethanone (21.4 g, 0.1 mol), acetone (365 mL) and pyrrolidine (8.4 mL) in toluene (220 mL) is refluxed for 4 h. To the reaction mixture is added acetone (36.5 mL), the mixture is refluxed for 15 h. Then 1 N HCl (220 mL) is added, extracted with ethyl acetate (200 mL 3×). The combined organic layers were washed with water (150 mL), brine (150 mL), dried over anhydrous Na2SO4, filtered, and evaporated to give 6-bromo-2,2-dimethyl-chroman-4-one (18 g, 71%).

Provenance & Evidence