C([O:3][C:4](=[O:15])[CH2:5][N:6]1[C:10]2=[N:11][CH:12]=[CH:13][CH:14]=[C:9]2[CH:8]=[N:7]1)C.O[Li].O.Cl>C1COCC1.O>[N:6]1([CH2:5][C:4]([OH:15])=[O:3])[C:10]2=[N:11][CH:12]=[CH:13][CH:14]=[C:9]2[CH:8]=[N:7]1To a stirred solution of pyrazolo[3,4-b]pyridin-1-yl-acetic acid ethyl ester (210 mg, 1.02 mmol) (Preparation 133) in THF (4 mL) and water (1 mL) at 0° C. was added LiOH.H2O (129 mg, 3.06 mmol). The reaction mixture was stirred at room temperature for 2 hours. The pH was of the mixture was adjusted to pH 4 with 2 N aqueous hydrochoric acid and extracted with 20% isopropanol in dichloromethane (8×5 mL). The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure to afford the title compound as an off-white solid in 40% yield, 70 mg.
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