反应详情

25% TFA/CH2Cl2 (10 mL) was added to tert-butyl 4-(5-chloro-1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridin-4-yl)piperazine-1-carboxylate (430 mg, 0.939 mmol), and the solution was stirred at room temperature. After 30 minutes, the solvent was removed under reduced pressure. The resulting residue was evaporated from toluene (3×10 mL) and dried under high vacuum for 18 hours to provide 5-chloro-1-(4-methoxybenzyl)-4-(piperazin-1-yl)-1H-pyrazolo[3,4-b]pyridine 2,2,2-trifluoroacetate. Neat TFA (10 mL) was added to this material, and the mixture was stirred at reflux for 90 minutes. TFA was removed under reduced pressure, and the residue was evaporated from CH2Cl2 (2×10 mL). The residue was redissolved in CH2Cl2, and 2M HCl in ether (6 mL) was added. The resulting suspension was concentrated in vacuo. The residue obtained was treated with 2M HCl in diethyl ether once more (5 mL) and subjected to sonication for 2 minutes. Then the solvent was removed in vacuo, and the resulting residue was triturated with Et2O. The solid formed was filtered, washed with ether (2×5 mL) and dried under high vacuum to provide 5-chloro-4-(piperazin-1-yl)-1H-pyrazolo[3,4-b]pyridine dihydrochloride (280 mg, 0.901 mmol, 62.0% yield) as a solid. LCMS (APCI+) m/z 238.0 (M+H)+.

1. customthe solvent was removed under reduced pressure
2. customThe resulting residue was evaporated from toluene (3×10 mL)
3. customdried under high vacuum for 18 hours