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

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Reaction Conditions

Reaction Steps

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

Provenance & Evidence