p-Toluenesulfonic acid → 3-Phenyl-2,4-pentanedione

Participants

Reaction Steps

Boron trifluoride-acetic acid (36%, 34.8 grams) was added with stirring dropwise to a solution of phenylacetone (4.46 grams), acetic anhydride, and para-toluenesulfonic acid (0.6 grams) in a water bath at room temperature. After stirring over night, a solid precipitate formed which was collected and washed with water and then refluxed in 100 ml water and sodium acetate (9.0 grams) for 2-3 hours. The original reaction mixture was also heated with 200 ml water and sodium acetate (13.5 grams) for the same period. Both mixtures were separately extracted with ether and then washed with saturated sodium bicarbonate solution to remove any acid. The ether portions were dried and then evaporated in vacuo leaving an oil which solidified, yield 1.4 grams, m.p. 40°-52° C.

Provenance & Evidence