Sodium Hydroxide → 1H-Pyrazolo(4,3-b)pyridine-6-carboxylic acid

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Reaction Steps

To a solution of methyl 1H-pyrazolo[4,3-b]pyridine-6-carboxylate (3.52 g, 20 mmol) in methanol (250 mL) and water (190 mL) at 0° C. was added aqueous sodium hydroxide (2M, 64 mL, 128 mmol), dropwise. The suspension was then allowed to warm to ambient temperature and stirred for 18 hours. The methanol was then removed in vacuo and the aqueous mixture extracted with ethyl acetate (250 mL) before being acidified (to pH 5-6) with aqueous hydrochloric acid (2 M, 70 mL). The cream solid which had precipitated out was then filtered off and dried in a desiccator to yield the title compound (0.675 g, 4.16 mmol, 21% yield). 1HNMR (400 MHz, DMSO-d6): 8 ppm 8.97 (s, 1H), 8.45 (s, 1H), 8.39 (s, 1H).

Provenance & Evidence