Potassium Hydroxide → 4-Chloro-1-ethyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid

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Reaction Steps

A solution of Intermediate 1 (3.5 g) in dioxane (28 ml) was treated with potassium hydroxide (6.3 g) as a solution in water (20 ml). The mixture was stirred for 2 h, then concentrated in vacuo, acidified to pH 3 with 2M aqueous hydrochloric acid and extracted with ethyl acetate. The layers were separated, the organic layer dried over sodium sulphate, then concentrated in vacuo to afford Intermediate 11 as a white solid (2.4 g). LCMS showed MH+=226; TRET=2.62 min.

Provenance & Evidence