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

Participants

Reaction Steps

A mixture of 6-(4-hydroxy-phenyl)-3-methyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid methyl ester (15.0 g), 3,4-dihydro-2H-pyran (24 mL) and p-toluenesulfonic acid monohydrate (3.0 g) in THF (400 mL) was stirred at r.t. until the reaction was complete. Water was added and the mixture was extracted with ethyl acetate, the combined organic phases were washed with water and brine, dried over magnesium sulfate and concentrated. The residue was chromatographed over a short path column (silica, heptane/ethyl acetate gradient). The product containing fractions were combined, concentrated, and the residue was triturated with ether to give 6-(4-hydroxy-phenyl)-3-methyl-1-(tetrahydro-pyran-2-yl)-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid methyl ester (11 g, 57% yield).

Provenance & Evidence