The general procedure for the synthesis of 2,6-dibromo-4-tert-butylaniline from 4-tert-butylaniline was as follows: 4-tert-butylaniline (24.2 g, 0.162 mol) was dissolved in 250 mL of acetic acid. A solution of bromine (17 mL, 0.324 mol) in acetic acid (30 mL) was added slowly dropwise to the above solution over a period of 3.5 hours under vigorous stirring. After the dropwise addition was completed, the reaction mixture was heated to 85 °C and maintained for 1.5 hours. After the reaction was completed, it was cooled to room temperature and the mixture was poured into 300 mL of ice water. The resulting mixture was treated with dilute aqueous sodium bicarbonate and 500 mL of ethyl acetate. The organic layer was separated, washed with water and dried with anhydrous sodium sulfate. After concentration, the product was purified by a short silica gel column (with petroleum ether as eluent) to give 44.5 g (89.5% yield) of 2,6-dibromo-4-tert-butylaniline. The structure of the product was confirmed by 1H NMR, 13C NMR and HRMS: 1H NMR (DMSO-d6, 500 MHz, ppm): δ 7.38 (s, 2H, Ar-H), 5.13 (s, 2H, NH2-H), 1.20 (s, 9H, C(CH3)3-H); 13C NMR (DMSO-d6, 125 MHz, ppm): δ 141.46, 140.36, 128.64, 107.68, 33.68, 30.92 ppm. HRMS (ESI): m/z calcd for [M + H+] C10H14Br2N: 307.9407; found: 307.9307.
