Uses
2,4-Dichloro-5-bromopyridine is an important biopharmaceutical intermediate widely used in the synthesis of various drugs. Its small molecular weight and unique structure allow for the derivation of numerous downstream products, giving it a wide range of applications.
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%).
