反应详情

4N NaOH (5.12 mL, 20.5 mmol) was added to a cold (0° C.) solution of 5-nitro-1H-pyrazolo[3,4-b]pyridine (0.84 g, 5.12 mmol) in dioxane (30 mL), followed by bromine (1.05 mL, 20.5 mmol). The cold bath was removed, and the reaction mixture was left at room temperature for 30 minutes. The reaction mixture was diluted with ethyl acetate (100 mL) and quenched with saturated Na2S2O3 (50 mL) The aqueous layer was extracted with ethyl acetate (100 mL). The combined organic layers were dried, filtered and concentrated. The crude product was purified by column chromatography, eluting with hexanes/ethyl acetate (9:1) to give 3-bromo-5-nitro-1H-pyrazolo[3,4-b]pyridine (1.10 g, 88%) as a solid.

1. customThe cold bath was removed
2. additionThe reaction mixture was diluted with ethyl acetate (100 mL)
3. customquenched with saturated Na2S2O3 (50 mL) The aqueous layer
4. extractionwas extracted with ethyl acetate (100 mL)
5. customThe combined organic layers were dried
6. filtrationfiltered
7. concentrationconcentrated
8. customThe crude product was purified by column chromatography
9. washeluting with hexanes/ethyl acetate (9:1)