p-Toluenesulfonic acid → 4,6-dichloro-1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazolo[3,4-d]pyrimidine

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Reaction Steps

p-Toluene sulfonic acid (p-TsOH, 30.2 mg, 0.159 mmol) was added to a solution of 4,6-dichloro-1H-pyrazolo[3,4-d]pyrimidine (300 mg, 1.587 mmol) and 3,4-dihydro-2H-pyran (200 mg, 2.381 mmol) in a mixture of THF:CH2Cl2 (1:1, 10 mL). The reaction mixture was stirred for 12 h at room temperature after which the solvent was removed in vacuo. The residue was taken up in CH2Cl2 (20 mL) and poured in water (20 mL). The organic phase was separated and the aqueous phase was extracted with CH2Cl2 (20 mL). The combined organic phases were washed with water (40 mL), then washed with brine (40 mL), dried over Na2SO4 and concentrated. The resulting crude material was purified by flash chromatography (CH2Cl2/CH3OH, 99/1 increasing) to yield the title compound (397 mg, 1.454 mmol, 92% yield) as a pale white oil which was used without further purification.

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