反应详情

t-Butyl 6-fluoro-1H-pyrazolo[3,4-b]pyridine-3-carboxylate (3.00 g, 0.0126 mole) was dissolved in 100 mL of toluene containing 10.85 g of piperazine (0.126 mole) and refluxed overnight. The resultant precipitate was filtered off and distributed between an aqueous NaHCO3 solution and EtOAc and then the organic phase was dried and concentrated to give a product which was recrystallized from CH3CN to give 1.57 g, mp 190°-191° C. The toluene filtrate was washed with NaHCO3 solution and then concentrated and purified by flash chromatography (EtOAc:MeOH:Et3N/16:2:2) to give an additional 1.38 g of product (total yield 77%).

1. temperaturerefluxed overnight
2. filtrationThe resultant precipitate was filtered off
3. customthe organic phase was dried
4. concentrationconcentrated
5. customto give a product which
6. customwas recrystallized from CH3CN
7. customto give 1.57 g, mp 190°-191° C
8. washThe toluene filtrate was washed with NaHCO3 solution
9. concentrationconcentrated
10. custompurified by flash chromatography (EtOAc:MeOH:Et3N/16:2:2)