6332-56-5

25391-59-7

3-Nitropyridin-2(1H)-one (10.3 g, 73.4 mmol, 1 eq.) was used as a raw material and suspended in a mixed solution of 46 mL acetic acid, 20 mL water, 1.4 mL concentrated sulfuric acid and periodate (3.5 g, 18 mmol, 0.25 eq.). The reaction mixture was stirred at 90 °C for 15 min until completely dissolved. Subsequently, iodine crystals (7.7 g, 30.1 mmol, 0.4 eq.) were added in batches and formation of a dense yellow precipitate was observed after 20 min of reaction. The reaction mixture was cooled to room temperature and 50 mL of saturated sodium thiosulfate solution was added to quench the reaction. The solid product was collected by filtration and washed sequentially with 50 mL of saturated sodium thiosulfate solution and water. Finally, the solid was dried under vacuum to give 5-iodo-3-nitropyridin-2-ol (XIII-2, 14 g, 72% yield).