Water → 3-methyl-1-(tetrahydro-pyran-2-yl)-6-[4-(tetrahydro-pyran-2-yloxy)-phenyl]-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid ethyl ester

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Reaction Conditions

Reaction Steps

To a mixture of 6-bromo-3-methyl-1-(tetrahydro-pyran-2-yl)-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid ethyl ester (6.00 g), 4-(tetrahydro-2H-pyran-2-yloxy)-phenylboronic acid (4.34 g) and potassium carbonate (2.93 g) in DME/water (v/v=2/1, 200 mL) was added at r.t. under Ar-atmosphere palladium(0) bis(tri-tert-butylphosphine) (0.42 g) and the mixture was stirred at 85° C. for 90 min. To the mixture water was added and it was extracted with ethyl acetate. The organic phase was washed with water, dried over magnesium sulfate, and concentrated in vacuo. The resulting residue was purified by flash chromatography (silica, heptane/ethyl acetate) to give 3-methyl-1-(tetrahydro-pyran-2-yl)-6-[4-(tetrahydro-pyran-2-yloxy)-phenyl]-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid ethyl ester (7.00 g, 92%). This material was dissolved in isopropanol (30 mL), and 1N sodium hydroxide solution (15 mL) was added. The solution was stirred overnight, then the mixture was contentrated in vacuo to about a third of its volume. The precipitated solid was isolated by filtration and dried in air giving the sodium salt of 3-methyl-1-(tetrahydro-pyran-2-yl)-6-[4-(tetrahydro-pyran-2-yloxy)-phenyl]-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid (6.2 g, 87%).

Provenance & Evidence