1-BROMO-2,4-DIFLUORO-5-NITROBENZENE synthesis
- Product Name:1-BROMO-2,4-DIFLUORO-5-NITROBENZENE
- CAS Number:345-24-4
- Molecular formula:C6H2BrF2NO2
- Molecular Weight:237.99
348-57-2
345-24-4
General procedure for the synthesis of 2,4-difluoro-5-bromonitrobenzene from 2,4-difluorobromobenzene: Concentrated HNO3 (34.0 mL) was added slowly and dropwise to a suspension of 1-bromo-2,4-difluorobenzene (53.0 mmol, 6.00 mL) in concentrated H2SO4 (38.5 mL) at 0 °C, ensuring that the internal temperature was maintained below 0 °C. The reaction mixture was stirred for 10 minutes with vigorous stirring. The reaction mixture was continued to be stirred at 0 °C for 10 min and subsequently poured into an ice/water mixture under vigorous stirring. The mixture was extracted with ether (ET20, 3 x 100 mL). The combined organic phases were washed sequentially with aqueous NaHCO3 (3 x 100 mL) and brine, dried over MgSO4, filtered and concentrated under reduced pressure. The crude product was purified by fast chromatography (eluent: EtOAc/hexane=1:9) to afford 5-bromo-2,4-difluoronitrobenzene as a yellow oil (12.2 g, 97% yield).1H NMR (400 MHz, CDCl3) δ 8.45 (t, 1H, J=7.5 Hz), 7.16 (dd, 1H, J=11.0,8.6 Hz) ; ESMS m/z: 240, 238, 223, 221, 112.
348-57-2
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345-24-4
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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
446-35-5
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345-24-4
135 suppliers
$8.00/1g