Synthesis
5-bromo-2-chloropyridine could be used as a starting material to synthesize 5-Bromo-2,4-dichloropyridine. At -100 °C, diisopropylamine (14 mL, 10 g, 0.10 mol) and 5-bromo-2-chloropyridine (19 g, 0.10 mol) were added consecutively to a solution of butyllithium (0.10 mol) in tetrahydrofuran (0.23 L) and hexanes (60 mL). After 45 min at -100 °C, the mixture was treated with 1,1,2-trichloro-1,2,2-trifluoroethane (12 mL, 19 g, 0.10 mol) and, after 45 min at -75 °C, with water (50 mL). Upon distillation, the product was collected as a colorless liquid, bp 60-62 °C/0.9 mmHg, yield 18.7 g (83%).
