p-Toluenesulfonic acid → HCID 19741682, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of 0.528 g (3 mmol) of 3'-allyl-2'-hydroxyacetophenone, 0.57 g (3.6 mmol) of 2-fluorobenzoyl chloride, 0.509 g (1.5 mmol) of tetra-n-butylammonium bisulfate, 20 ml of 10% aqueous potassium hydroxide and 20 ml of benzene was heated at 80° C. for 3 hours. The layers were separated and the benzene layer washed thoroughly with water (3×20 ml) and the water removed from the benzene layer by azeotropic distillation. The resulting residue was treated with 1.7 g (9 mmol) of p-toluenesulphonic acid and benzene (25 ml) and heated for two hours with azeotropic removal of water. The benzene solution was washed with 8% aqueous sodium bicarbonate (50 ml) and the solvent evaporated in vacuo. The resulting residue was recrystallized from ethyl acetate to give 0.49 g (58%) of 8-allyl-2-(2-fluorophenyl)-4H-benzopyran-4-one as white solid: M.P. 78°-81° C.; TLC R f 0.40 in 10:1 hexane-ethylacetate.

Provenance & Evidence