3-Bromo-2,4-difluoronitrobenzene 98% synthesis

Yield: 97%

Reaction Conditions:

with nitric acid in sulfuric acid

Steps:

43.A 2,4-Difluoro-3-bromo-1-nitrobenzene
A. A solution of 1,3-difluoro-2-bromobenzene (23.5 g, 112 mmol) in concentrated sulfuric acid (48 ml) was stirred vigorously at ambient temperature. Concentrated nitric acid (70%, 8 ml) was added dropwise such that the internal temperature of the reaction mixture did not exceed 55° C. The reaction mixture was then stirred from 15 minutes and poured onto ice (300 ml). The aqueous mixture was extracted three times with methylene chloride. The combined organic layers were washed three times with a saturated sodium bicarbonate solution, dried over magnesium sulfate and filtered. Solvent was removed in vacuo to give a yellow solid. Recrystallization from isopropyl ether afforded a white solid (28.2 g, 97% yield): m.p. 50°-51.5° C. NMR (CDCl3, 60 MHz): 8.4-7.9 (m, 1H), 7.4-7.0 (m, 1H). Anal.: Calcd. for C6H2BrF2NO2: C, 30.28, H, 0.85, N, 5.89, Br, 33.57, F, 15.96. Found: C, 30.34, H, 0.98, N, 5.81, Br, 33.81, F, 16.04.

References:

Pfizer Inc. US4623650, 1986, A