4-(3-Fluorophenyl)butanoic acid → 6-Fluoro-1,2,3,4-tetrahydronaphthalen-1-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 4-(3-fluorophenyl)butanoic acid (10 g) and polyphosphoric acid (100 g) was heated to 70° C. with stirring for 2 h. The reaction mixture was cooled and water was carefully added (400 cm3). The aqueous mixture was extracted with diethyl ether (3×75 cm3) and the combined extracts were washed sequentially with aqueous potassium hydroxide solution (1 M, 75 cm3), water (75 cm3) and saturated aqueous sodium chloride solution (75 cm3). The combined organic extracts were dried (Na2SO4), and the solvent was distilled off under reduced pressure. The crude product (6.58 g) was purified by column chromatography [silica, eluting with petroleum ether (b. p. 40-60° C.)-ethyl acetate (20:1)] to afford the title compound (6.36 g).

Provenance & Evidence