Trifluoroacetic acid → benzyl 4-[4-amino-3-(4-amino-3-methoxyphenyl)-1H-pyrazolo[3,4-d]pyrimidin-1-yl]-1-piperidinecarboxylate

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Reaction Steps

To a mixture of benzyl 4-(4-amino-3-{4-[(tert-butoxycarbonyl)amino]-3-methoxyphenyl}-1H-pyrazolo[3,4-d]pyrimidin-1-yl)-1-piperidinecarboxylate (7.68 g, 0.0134 mol) in dichloromethane (10 mL) was added a 25% solution of trifluoroacetic acid in dichloromethane at 0° C. The mixture was stirred under an atmosphere of nitrogen at room temperature for 18 hours. The solvents were removed under reduced pressure. The residue was cooled to 0° C. and basified with an aqueous 5 N solution of sodium hydroxide. The aqueous layer was extracted with dichloromethane (3×150 mL). The combined organic layer was washed with water and brine, and dried over magnesium sulfate. The solvents were removed under reduced pressure to give benzyl 4-[4-amino-3-(4-amino-3-methoxyphenyl)-1H-pyrazolo[3,4-d]pyrimidin-1-yl]-1-piperidinecarboxylate (6.02 g, 0.0127 mol).

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