25391-57-5

426463-05-0

b) General procedure for the synthesis of 2-chloro-5-iodo-3-nitropyridine from 2-amino-5-iodo-3-nitropyridine: 5-iodo-3-nitropyridin-2-amine (1.3 g, 4.9 mmol) was dissolved in concentrated hydrochloric acid at 0 °C, followed by slow addition of sodium nitrite (6.73 g, 97.13 mmol). Next, a solution of 20 molar equivalents of copper (I) bromide was added dropwise, followed by copper (I) chloride (0.5 g, 4.9 mmol, 1 equiv). The reaction mixture was stirred at room temperature for 12 hours. Upon completion of the reaction, the mixture was poured into a mixture of ammonium hydroxide and water (1:1, v/v) and extracted with ethyl acetate (3 x 150 mL). The organic phases were combined and washed sequentially with water, aqueous sodium thiosulfate and saturated saline, and dried over anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure to afford the target product 2-chloro-5-iodo-3-nitropyridine in 43% (0.6 g) yield.