Potassium Carbonate → HCID 86699543, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of 2,4-difluorophenol (1.9 g, 14.61 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. Then the reaction was quenched with water (200 ml) and extracted with ethyl acetate (3×100 ml) and the organic layers combined and dried over anhydrous magnesium sulfate. The organic layers were concentrated under vacuum to give a residue, which was purified by a silica gel column with 2%˜5% ethyl acetate in petroleum ether to produce 4-chloro-5-(4-fluoro-2-methylphenoxy)-2-nitroaniline as a yellow solid (1.3 g, 30%). Next, to a solution of 4-chloro-5-(2,4-difluorophenoxy)-2-nitroaniline (1.3 g, 4.32 mmol) in ethanol (20 ml) was added hydrogen chloride (conc. 1 ml) followed by the addition of Zn powder (1.7 g, 25.92 mmol) in portions at room temperature. The resulting solution was stirred for 4 h at 85° C. The resulting mixture was concentrated under vacuum and dissolved in water (150 ml), adjusted pH to 8 with aqueous sodium bicarbonate. The mixture was extracted with ethyl acetate (3×100 ml), dried and concentrated under reduced pressure to give a residue, which was purified by a silica gel column with 10%˜20% ethyl acetate in petroleum ether to produce 4-chloro-5-(2,4-difluorophenoxy)benzene-1,2-diamine as a light yellow solid (600 mg, 51%). Finally, a solution of 4-chloro-5-(2,4-difluorophenoxy)benzene-1,2-diamine (100 mg, 0.37 mmol) in hydrogen chloride (conc. 2 ml) and TFA (10 ml) was stirred overnight at 80° C. The solution was quenched with water (100 ml), adjusted pH value of the solution to 7 with aqueous sodium bicarbonate and extracted with ethyl acetate (3×50 ml) and the organic layers combined and dried over anhydrous magnesium sulfate. The solids were filtered out. The resulting mixture was concentrated under vacuum to give a residue, which was purified by a silica gel column with 5%˜10% ethyl acetate in petroleum ether to produce 5-chloro-6-(2,4-difluorophenoxy)-2-(trifluoromethyl)-1H-1,3-benzodiazole as a white solid (73.5 mg, 57%).

Provenance & Evidence