反应详情

温度

70 °C

4-Hydroxy-1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester was dissolved in ethanol (20 mL), and a sodium hydroxide solution (5 M, 6 mL) was added thereto. The resulting mixture was stirred at 70° C. for 2 hours, and a hydrochloric acid solution (5 M, 6 mL) was added thereto under ice-cooling. The precipitate was collected by filtration and washed with water. The obtained solid was suspended in a methanol-toluene solvent mixture and concentrated under reduced pressure to give 4-hydroxy-1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid (2.89 g, 98%) as a colorless powder.

1. temperatureunder ice-cooling
2. filtrationThe precipitate was collected by filtration
3. washwashed with water
4. concentrationconcentrated under reduced pressure