反应详情

16.5 g. of 1-ethyl-4-hydroxy-5-(2-phenylethyl)-1H-pyrazolo[3,4-b]pyridine-6-carboxaldehyde, hydrochloride (1:1) (0.05 mol.) are dissolved in 150 ml. of boiling glacial acetic acid. To the filtered solution, cooled to about 30°, 10 g. of H2O2 (35%) (0.1 mol.) are added in two portions and the mixture is allowed to stand for 20 hours at room temperature. The crystallized 1-ethyl-4-hydroxy-5-(2-phenylethyl)-1H-pyrazolo[3,4-b]pyridine-6-carboxylic acid is filtered off, washed with acetic acid and ether, yield: 10.1 g. (65%); m.p. 250°-251° (ethanol).

1. temperatureTo the filtered solution, cooled to about 30°
2. filtrationThe crystallized 1-ethyl-4-hydroxy-5-(2-phenylethyl)-1H-pyrazolo[3,4-b]pyridine-6-carboxylic acid is filtered off
3. washwashed with acetic acid and ether, yield: 10.1 g