Sodium Hydroxide → 6-(4-Methoxymethoxy-phenyl)-3-methyl-1-(tetrahydro-pyran-2-yl)-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid

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Reaction Steps

To 2.09 g 6-(4-methoxymethoxy-phenyl)-3-methyl-1-(tetrahydro-pyran-2-yl)-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid ethyl ester in 140 ml ethanol was added 100 ml of 1M aqueous sodium hydroxide solution. After 3 h at r.t. the volatiles were removed in vacuo. The residue was taken up in water and the pH was adjusted to 4-5. The aqueous phase was extracted with ethyl acetate three times. The combined organic phases were dried over Na2SO4, filtered and concentrated in vacuo. The residue was purified by flash chromatography (silica, dichloromethane/MeOH gradient with addition of aqueous ammonia) to obtain 1.74 g (90%) of the title compound.

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