反应详情

3 g of 4-hydroxy-1-(4-picolyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester (0.01 mol) is dissolved in 20 ml of acetic acid. 2.2 g of selenium dioxide (0.02 mol) and 2-3 drops of water are added. The mixture is refluxed for 30 minutes and then filtered off. 4-Hydroxy-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester precipitates on cooling. Recrystallization from acetic acid yields 1.8 g (87%), m.p. 275°.

1. temperatureThe mixture is refluxed for 30 minutes
2. filtrationfiltered off
3. custom4-Hydroxy-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester precipitates
4. temperatureon cooling
5. customRecrystallization from acetic acid
6. customyields 1.8 g (87%), m.p. 275°