反应详情

tert-Butyl 4-(1-(4-methoxybenzyl)-5-methyl-1H-pyrazolo[3,4-b]pyridin-4-yl)piperazine-1-carboxylate (465 mg, 1.06 mmol) in 25% TFA/CH2Cl2 (25 mL) was stirred at room temperature for 2 hours. The solvent was removed, and the gum obtained was evaporated from toluene (3×20 mL; water bath 60° C.). Neat TFA was added to the residue and stirred at reflux for 3 hours. Next, TFA was removed under reduced pressure, and the resulting residue was evaporated form CH2Cl2 (2×10 mL). The residue was resuspended in CH2Cl2 (2 mL), and 2M HCl in diethyl ether (5 mL) was added. The resulting suspension was concentrated in vacuo, and the residue was crystallized from boiling EtOH to provide 5-methyl-4-(piperazin-1-yl)-1H-pyrazolo[3,4-b]pyridine dihydrochloride (175 mg, 0.603 mmol, 56.7% yield) as a powder after drying under high vacuum for 4 hours. LCMS (APCI+) m/z 218.1 (M+H)+.

1. customThe solvent was removed
2. customthe gum obtained
3. customwas evaporated from toluene (3×20 mL; water bath 60° C.)
4. additionNeat TFA was added to the residue
5. temperatureat reflux for 3 hours
6. customNext, TFA was removed under reduced pressure
7. customthe resulting residue was evaporated form CH2Cl2 (2×10 mL)
8. addition2M HCl in diethyl ether (5 mL) was added
9. concentrationThe resulting suspension was concentrated in vacuo
10. customthe residue was crystallized