Potassium Hydroxide → 4-Ethoxy-1-ethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid

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Reaction Steps

263 g. of 4-Ethoxy-1-ethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester (1 mol.) are heated with a solution of 114 g. of potassium hydroxide (2 mol.) in 1 liter of ethanol at 60° for 12 hours. After this time, the solvent is removed in vacuo and the residue is dissolved in 1.5 liters of water. After acidifying with acetic acid, 4-ethoxy-1-ethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid precipitates. Recrystallization from alcohol yields 215 g. (91%), m.p. 198°-199°.

Provenance & Evidence