p-Toluenesulfonic acid → 4-Chloro-4'-methoxybutyrophenone

Participants

Reaction Steps

A solution of 45.96 g. (0.217 mole) of 4-chloro-4 -methoxybutyrophenone [prepared in (a), above], 28 g. (0.27 mole) of 2,2-dimethyl-1,3-propanediol and 0.53 g. of p-toluenesulfonic acid in 425 ml. of benzene is heated at reflux under a Dean-Stark trap for about 20 hours. The solution is allowed to cool, washed successively with aqueous sodium bicarbonate solution, water and brine and then evaporated to dryness. The residue is distilled at 174° C. at 1.5 mm. of mercury pressure and then recrystallized from petroleum ether to give 19.97 g. (30.9% yield) of 4-chloro-4'-methoxybutyrophenone, 2,2-dimethylpropylene ketal, having a melting point of 51.5 ° to 53.5° C.

Provenance & Evidence