Hydrogen Bromide → 2-Bromo-1-ethyl-3-nitrobenzene

A suspension of 2-ethyl-6-nitroaniline (1.7 g, 10 mmol) in water (10 mL) and aqueous HBr (5 mL, 40%, 25 mmol) was refluxed for 10 minutes and then cooled to 0° C. A solution of NaNO2 (0.7 g, 10 mmol) in H2O (4 mL) was added dropwise at a temperature <10° C. The diazonium-containing solution was stirred for 30 minutes at a temperature of 0° C. to 5° C. and was then slowly added to a stirred mixture of CuBr (1.4 g, 10 mmol) in aqueous HBr (4 mL, 40%, 20 mmol) and water (8 mL) at RT. The mixture was stirred at RT for 30 minutes and then on a steam bath for 1 hour. The mixture was subsequently washed with aqueous saturated NaHCO3 and brine, dried over MgSO4, and concentrated. The residue was purified by column chromatography eluting with petroleum ether to give the title compound as a pale yellow oil (1.7 g, 75%). 1H NMR (400 MHz, CDCl3) δ 7.50 (1H, dd, J=7.6, 1.6 Hz), 7.43 (1H, dd, J=8.0, 1.6 Hz), 7.37 (1H, dd, J=8.0, 7.6 Hz), 2.88 (2H, q, J=7.6 Hz), 1.28 (3H, t, J=7.6 Hz).