3-(4-Fluorophenyl)-2-methylpropanoic acid → 6-Fluoro-2-methylindan-1-one

Participants

Reaction Conditions

Reaction Steps

To 932 g polyphosphoric acid at 70° C. (on the steam bath) is added p-fluoro-α-methylhydrocinnamic acid (93.2 g, 0.5 mol) slowly with stirring. The temperature is gradually raised to 95° C., and the mixture is kept at this temperature for 1 hour. The mixture is allowed to cool and added to 2l. of water. The aqueous layer is extracted with ether, the ether solution is washed twice with saturated sodium chloride solution, 5% Na2CO3 solution, water, and is then dried. The ether filtrate is concentrated with 200 g silica-gel, and is added to a five pound silica-gel column packed with 5% ether-petroleum ether. The column is eluted with 5-10% ether-petroleum ether, to give 6-fluoro-2-methylindanone. Elution is followed by TLC.

Provenance & Evidence