Sodium Sulfite → HCID 178440164, compound

[step 1] 2-Propylimidazole (3.0 g, 27.3 mmol) was dissolved in dioxane/water (55 mL/55 mL), sodium hydrogen carbonate (8.67 g, 81.8 mmol) and iodine (15.0 g, 59.9 mmol) were added, and the mixture was stirred at room temperature overnight. Water was added to the reaction mixture and the mixture was extracted 3 times with ethyl acetate. The combined organic layer was dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to give 4,5-diiodo-2-propylimidazole (7.09 g, 72%). [step 2] 4,5-Diiodo-2-propylimidazole (3.0 g, 8.31 mmol) obtained in Reference Example A16, step 1 was dissolved in ethanol/water (60 mL/60 mL), sodium sulfite (8.40 g, 66.5 mmol) was added, and the mixture was heated under reflux overnight. After completion of the reaction, the mixture was extracted 3 times with chloroform. The combined organic layer was dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to give 4-iodo-2-propylimidazole (1.73 g, 88%).