反应详情

1-Ethyl-4-hydroxy-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester (10.0 g, 42.6 mmol) was suspended in 50 mL EtOH. To this suspension was added 6 N NaOH (21.3 mL, 3 eq). The resulting light brown solution was heated at reflux for 3 hr before being diluted with 100 mL water. The aqueous solution was extracted with diethyl ether (50 mL×3) and the organic layer was discarded. The aqueous layer was acidified with 1 N HCl and a white precipitate formed. The title compound was collected by filtration and rinsed with water and diethyl ether affording a white solid (7.9 g, 90%): mp 218° C. (decomposed); LRMS (m/z) 208 (MH+).

1. temperatureThe resulting light brown solution was heated
2. temperatureat reflux for 3 hr
3. extractionThe aqueous solution was extracted with diethyl ether (50 mL×3)
4. customa white precipitate formed
5. filtrationThe title compound was collected by filtration
6. washrinsed with water and diethyl ether affording a white solid (7.9 g, 90%)