Hydrogen Bromide → 3-Bromo-4-(trifluoromethyl)benzoic acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

3-Amino-4-trifluoromethylbenzoic acid (8.20 g, 40.0 mmol), prepared according to Astrid Giencke and Helmut Lackner, Liebigs Ann. Chem., 569-579:6 (1990), in 48% HBr (20 mL) and H2O (67 mL) at 0° C. was treated with NaNO2 (2.99 g) in small portions over 15 minutes. After stirring for 30 minutes, the mixture was treated with urea (0.250 g) and then the mixture was added dropwise to a solution of CuBr (10.0 g) in 48% HBr (40 mL) and H2O (100 mL). The reaction mixture was heated at 75° C., stirred for 2 hours, cooled to room temperature, and stirred overnight. The mixture was treated with with 20% NaOH until the pH>10. The resulting blue copper salts were removed by filtration through Celite. The mixture was acidified to pH 1 with HCl, extracted with CH2Cl2 (3×200 mL), dried over Na2SO4, filtered, and the filtrate was concentrated under reduced pressure to provide the title compound.

Herkunft & Nachweise