Water (5 mL) and lithium hydroxide (1.5 g, 63 mmol) were added to a solution of ethyl 4-{(3S)-3-[(tert-butoxycarbonyl)amino]piperidin-1-yl}-1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (1.9 g, 3.7 mmol) in MeOH (5 mL) and THF (5 mL). The mixture heated at 50° C. with stirring for 2 h. The mixture was allowed to cool to room and concentrated under reduced pressure. The residue was neutralized with 2N HCl and extracted twice with EtOAc. The organic extract was dried with Na2SO4 and concentrated under reduced pressure to give the sub-title compound (1.6 g (89%). LCMS calc. for C25H32N5O5 (M+H)+: m/z=482.2. Found: 482.1.
