反应详情

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).

1. extractionthe mixture was extracted with ethyl acetate
2. washthe combined organic phases were washed with water and brine
3. dry with materialdried over magnesium sulfate
4. concentrationconcentrated
5. customThe residue was chromatographed over a short path column (silica, heptane/ethyl acetate gradient)
6. additionThe product containing fractions
7. concentrationconcentrated
8. customthe residue was triturated with ether