Example 1 Preparation of 2,6-dibromo-4-(6-(3-bromobenzyloxy)pyridazin-3-yl)phenol (Compound 91): to a stirred solution of 2,6-dibromophenol (5.26 g, 20.9 mmol) in acetone (170 mL) was added anhydrous potassium carbonate (4.33 g, 31.3 mmol) and the mixture was stirred at room temperature for 30 minutes. Iodomethane (1.97 mL, 31.4 mmol) was then added and the reaction mixture was heated to reflux at 60 °C for 3 hours. After completion of the reaction, the mixture was filtered and the filtrate was concentrated by rotary evaporation. The residue was extracted by partitioning between petroleum ether (40-60 °C, 100 mL) and water (100 mL). The aqueous layer was extracted once more with petroleum ether (40-60 °C, 100 mL), and the organic phases were combined, washed with brine (50 mL), dried over anhydrous magnesium sulfate, filtered, and concentrated to afford 5.43 g (98% yield) of the target compound, 1 ,3-dibromo-2-methoxybenzene, as a colorless oil.1H NMR (CDCl3, δ ppm): 3.89 (3H, s), 6.86 (1H, t, J = 8.02 Hz), 7.50 (2H, d, J = 8.01 Hz).
