Hydrochloric Acid → 6-(4-Hydroxy-phenyl)-3-methyl-1-(tetrahydro-pyran-2-yl)-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid

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Reaction Steps

A mixture of 6-(4-hydroxy-phenyl)-3-methyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid methyl ester (10.9 g) and sodium hydroxide solution (1N, 80 mL) in isopropanol (80 mL) was stirred at r.t. for 90 min. The pH was adjusted to 3 with 1N HCl and the mixture was poured onto water. The precipitate formed was filtered off and dried in air to give 6-(4-Hydroxy-phenyl)-3-methyl-1-(tetrahydro-pyran-2-yl)-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid (10.2 g, 97% yield).

Provenance & Evidence