4-Fluorophenol → HCID 86699554, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of 4-fluorophenol (1.63 g, 14.54 mmol) in DMSO (20 ml) was added 4,5-dichloro-2-nitroaniline (3 g, 14.49 mmol) and potassium carbonate (4 g, 28.94 mmol) with stirring overnight at 90° C. The reaction was then quenched by the addition of water (200 ml), extracted with ethyl acetate (3×100 ml) and dried over anhydrous magnesium sulfate. The solids were filtered out and the filtrate was concentrated under vacuum to give a residue, which was purified by a silica gel column with 2% to 10% ethyl acetate in petroleum ether to produce 4-chloro-5-(4-fluorophenoxy)-2-nitroaniline as a yellow solid (2.0 g, 49%). Next, to a solution of 4-chloro-5-(4-fluorophenoxy)-2-nitroaniline (2 g, 7.08 mmol) and hydrogen chloride (1.8 ml) and ethanol (25 ml) was added Zn powder (2.8 g) in portions at room temperature. The resulting solution was stirred for 4 h at 85° C. and then concentrated under vacuum. The residue was dissolved in water (300 ml), pH adjusted to 8 with aqueous sodium bicarbonate and extracted with ethyl acetate (3×80 ml). The combined organic layers were dried and concentrated under reduced pressure to give a residue, which was purified by a silica gel column with 10% ethyl acetate in petroleum ether to produce 4-chloro-5-(4-fluorophenoxy)benzene-1,2-diamine as red oil (1 g, 83%). Finally, a solution of 4-chloro-5-(4-fluorophenoxy)benzene-1,2-diamine (400 mg, 1.58 mmol) in 2,2-difluoro-3,3-dimethylbutanoic acid (4 ml) was stirred overnight at 95° C. in an oil bath. Then the solution was poured into water (100 ml), adjusted to pH 8 with saturated aqueous sodium bicarbonate and extracted with ethyl acetate (3×50 ml). The combined organic layers were dried over anhydrous sodium sulfate and concentrated under vacuum to give a residue, which was purified by a silica gel column with 10% ethyl acetate in petroleum ether to produce 5-chloro-6-(4-fluorophenoxy)-2-(pentafluoroethyl)-1H-1,3-benzodiazole as a white solid (19.9 mg, 3%).

Provenance & Evidence