Acetone → 7-fluoro-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-4-one

Participants

Reaction Steps

A mixture of 4-fluoro-2-hydroxyacetophenone (Aldrich, 1.54 g, 10 mmol), acetone (0.95 mL, 12.9 mmol), and pyrrolidine (0.83 mL, 9.94 mmol) was stirred in 3 mL toluene at room temperature for 1 h and at reflux (Dean-Stark trap) for 4 hours. After cooling to room temperature, the mixture was diluted with ether (30 mL) and was washed with 2N HCl (10 mL) and H2O (10 mL). Drying over Na2SO4 and evaporation of volatiles in vacuo afforded the crude title compound, which was used without further purification.

Provenance & Evidence