Potassium Hydroxide → HCID 19741667, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of 1.7 g (9.4 mmol) of 3'-allyl-2'-hydroxyacetophenone, 2.0 g (11 mmol) of 3,4-difluorobenzoyl chloride, 1.6 g (4.7 mmol) of tetra-n-butylammonium bisulfate, 60 ml of 10% aqueous potassium hydroxide and 60 ml of benzene was heated at 60° C. for 4 hours, cooled and the phases separated. The organic phase was washed with three 60 ml portions of water, treated with 5.6 g (28 mmol) of p-toluenesulfonic acid monohydrate and an additional 60 ml of benzene and refluxed for 3 hours, using a Dean-Stark trap to remove the water in the reaction. The resulting mixture was washed with 150 ml of 8% aqueous sodium bicarbonate and then with three 60 ml portions of water. The organic phase was then concentrated in vacuo; treated with 25 ml of methanol and cooled to -20° C. After four hours the resulting solid was filtered, washed with three 5 ml portions of methanol and dried to give 1.62 g (56%) of 8-allyl-2-(3,4-difluorophenyl)-4H-benzopyran-4-one as a solid: m.p. 127°-130° C.; TLC Rf 0.48 in 3:1 toluene-methyl isobutyl ketone.

Provenance & Evidence