25391-58-6

5418-51-9

25391-58-6

Synthesis of 3-iodo-5-nitropyridin-2-ol (CXXI): a mixture of 2-hydroxy-5-nitropyridine (14 g, 99.9 mmol) and potassium carbonate (13.8 g, 99.9 mmol) was dissolved in N,N-dimethylformamide (100 mL). Iodine (25.3 g, 99.7 mmol) was added in batches at room temperature. The reaction mixture was heated at 85 °C for 15 h and subsequently cooled to room temperature. The reaction process was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the mixture was diluted with water (150 mL) and extracted with ethyl acetate (75 mL x 3). The organic phases were combined, washed with brine (150 mL × 3), dried over anhydrous sodium sulfate, and subsequently concentrated in vacuum. The residual solid was washed with hexane (50 mL × 2) and dried under a stream of air to afford the brown solid CXXI (14 g, 53% yield), which could be used in subsequent reactions without further purification.