Trifluoroacetic acid → 4-Amino-3-fluorobenzonitrile

Participants

Reaction Conditions

Reaction Steps

Trifluoroacetic acid (1 ml) was added dropwise to a solution of 3-fluoro-4-[(4-methoxybenzyl)amino]benzonitrile (1.0 g, 3.9 mmol), obtained in Example 25(1), in anhydrous dichloromethane (20 ml) cooled to 0° C. with stirring. The resulting mixture was stirred at room temperature overnight. At the end of this time, the reaction mixture was poured into saturated aqueous sodium hydrogencarbonate solution at 0° C. The resulting mixture was partitioned between ethyl acetate and water. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residual oil was chromatographed on a silica gel column using ethyl acetate-hexane (1:6) as the eluant to afford 4-amino-3-fluorobenzonitrile (252 mg, yield 47%) as a pale orange solid which was recrystallized from ethyl acetate-hexane to give white powdery crystals. Melting point: 84° C.

Provenance & Evidence