反应详情

A solution of 4-nitro-1H-indazole (50.0 g; 306 mmol) in N,N-dimethylformamide (600 mL) was cooled to 5° C. under a nitrogen atmosphere with stirring. Powdered potassium hydroxide (68.8 g; 1226 mmol) was added. A solution of iodine (156 g; 613 mmol) in DMF (200 mL) was added slowly to the reaction mixture over 2 hours maintaining the temperature between 5 and 10° C. The mixture was stirred at 25° C. for 24 hours. Additional iodine (39.0 g; 153.2 mmol) and potassium hydroxide (17.2 g; 306.5 mmol) was added. The mixture was stirred at 25° C. for a further 12 hours. The reaction mixture was added to an aqueous solution of sodium bisulfite (10% solution; 3300 mL) with stirring. The resulting precipitate was collected by filtration and washed with water. The material was dried in a vacuum oven at 40° C. The material was dissolved in methylene chloride/methanol (10:1; 1.5 L) and filtered through Celite® to remove inorganic impurities. Concentration of the solution under vacuum gave 3-iodo-4-nitro-1H-indazole as a yellow solid (75 g).

1. temperaturemaintaining the temperature between 5 and 10° C
2. stirringThe mixture was stirred at 25° C. for 24 hours
3. stirringThe mixture was stirred at 25° C. for a further 12 hours
4. stirringwith stirring
5. filtrationThe resulting precipitate was collected by filtration
6. washwashed with water
7. customThe material was dried in a vacuum oven at 40° C
8. dissolutionThe material was dissolved in methylene chloride/methanol (10:1; 1.5 L)
9. filtrationfiltered through Celite®
10. customto remove inorganic impurities