To a solution of tert-butyl 4-{3-(cyanomethyl)-3-[4-(7-{[2-(trimethylsilyl)ethoxy]methyl}-7H-pyrrolo[2,3-d]pyrimidin-4-yl)-1H-pyrazol-1-yl]azetidin-1-yl}-2-methylpiperidine-1-carboxylate (0.5 g) in methanol (2 mL) was added 10 mL of a 4.0 N solution of hydrogen chloride in 1,4-dioxane (40 mmol). The resulting solution was stirred at room temperature for an hour. The solvents were removed under reduced pressure to give 0.5 g (99%) of {1-(2-methylpiperidin-4-yl)-3-[4-(7-{[2-(trimethylsilyl)ethoxy]methyl}-7H-pyrrolo[2,3-d]pyrimidin-4-yl)-1H-pyrazol-1-yl]azetidin-3-yl}acetonitrile as a white solid. LC-MS: 507.1 (M+H)+.
