Ethanol → 2-Fluoro-4'-aminobenzophenone

Participants

Reaction Steps

To stirred 90° C. polyphosphoric acid (200 g) was added 14.29 g (10.2 mmol) of 2-fluorobenzoic acid and aniline (9.32 g 10.0 mmol) and the bath temperature raised to 180°-190° C. and held there for 1 hour. A solution was obtained at about 140° C. The heating bath was removed and the stirred mixture (sublimate above the solution) was treated cautiously with 80 mL of water. The mixture was stirred at 140°-155° C. for 1 hour, the heating bath removed, 66 mL of 3N HCl added, the mixture poured into 1 L of water and filtered through a pad of Celite. The filtrate was basified with 15% sodium hydroxide and the solid which formed on stirring was collected. The Celite pad was washed well with methylene chloride, the methylene chloride removed and the residue was combined with the solid obtained from basification of the aqueous phase. The combined material was dissolved in refluxing ethanol (175 mL), and treated hot with 125 mL of water. The brown solid obtaing on cooling was additionally recrystallized twice from ethyl acetate-hexane. Final purification by flash column chromatography (methylene chloride) yielded the aniline as a white solid (5.45 g, 25%); mp 128°-130° C. 1H--NMR (250 MHz, d6 --DMSO): 6.32 (s, 2H, NH2) 6.60 (dd, 2H, J=8.6, 1.5 Hz, aromatic) 7.28-7.35 (m, 2H, aromatic) 7.40-7.60 (m, 4H, aromatic). MS (CI, CH4): 216 (M+1).

Provenance & Evidence