反应详情

6-Chloroimidazo[1,2-b]pyridazine (4.95 g, 31.6 mmol) [purchased from Combi-Blocks] was dissolved in 60 mL concentrated sulfuric acid, cooled in an ice bath, and nitric acid (9.9 mL, 158 mmol) was added dropwise while stirring. The reaction was stirred at 0° C. for 30 minutes, then at ambient temperature for 4.5 hours to reach completion. The reaction was poured onto ice, and the resulting aqueous mixture was neutralized with 50% NaOH aqueous solution and then extracted with EtOAc (3×400 mL). The organic layers were combined and washed with water (2×400 mL) and brine (400 mL), dried (Na2SO4), filtered and concentrated to yield the product as a yellowish powder (5.7 g, 91% yield).

1. temperaturecooled in an ice bath
2. stirringThe reaction was stirred at 0° C. for 30 minutes
3. additionThe reaction was poured onto ice
4. extractionextracted with EtOAc (3×400 mL)
5. washwashed with water (2×400 mL) and brine (400 mL)
6. dry with materialdried (Na2SO4)
7. filtrationfiltered
8. concentrationconcentrated