1-BROMO-2,4-DIFLUORO-5-NITROBENZENE synthesis

Yield:345-24-4 97%

Reaction Conditions:

with sulfuric acid;HNO₃ in lithium hydroxide monohydrate at 0 - 20; for 0.166667 h;

Steps:

II.f 5-BROMO-2,4-DIFLUORONITROBENZENE.

To a suspension of [1-] bromo-2,4-difluorobenzene (53.0 mmol, 6.00 mL) in concentrated [H2SO4] (38.5 mL) at [0 C] was added dropwise concentrated HN03 (34.0 mL) maintaining internal temperature below [20 C.] The resulting mixture was stirred for 10 min at [0 C,] then poured into ice/water with vigorous stirring. The mixture was extracted with [ET20] (3 x 100 mL). The combined organic extracts were washed with aqueous [NAHC03] solution (3 x 100 mL) and brine, dried over [MGSO4,] filtered and concentrated in vacuo. The crude product was purified by flash chromatography (EtOAc: hexanes 1: 9) to afford 5-bromo-2,4- difluoronitrobenzene as a yellow oil (12.2 g, [97%). LH] NMR (400 MHz, [CDC13)] [5] 8.45 (t, 1H, J = 7.5 Hz), 7.16 (dd, 1H, J = 11.0, 8.6 Hz); ESMS [M/E] : 240,238, 223,221, 112

References:

WO2004/5257,2004,A1 Location in patent:Page 67