反应详情

Furopyridine (8, 0.71 g, 5.96 mmol) is treated with n-butyl lithium (2.5M in hexane, 2.86 ml, 7.15 mmol) in anhydrous THF (30 ml) at −78° C. After 30 minutes, dry carbon dioxide is passed through the reaction mixture and the temperature is allowed to rise gradually to room temperature in 3 hours. The mixture is concentrated to dryness. The residue is dissolved in water (˜10 ml) and extracted with ethyl acetate. The aqueous layer is acidified to pH˜3 with 1N HCl and kept in the refrigerator over night. The resulting precipitates are filtered and dried to give azabenzofuran carboxylic acid as a white powder (9)

1. waitto rise gradually to room temperature in 3 hours
2. concentrationThe mixture is concentrated to dryness
3. dissolutionThe residue is dissolved in water (˜10 ml)
4. extractionextracted with ethyl acetate
5. waitkept in the refrigerator over night
6. customThe resulting precipitates
7. filtrationare filtered
8. customdried