To a solution of racemic ethyl 3-[[5-fluoro-2-(5-fluoro-1-trityl-pyrazolo[3,4-b]pyridin-3-yl)pyrimidin-4-yl]amino]-3-(1-methylcyclopentyl)propanoate, 148a, (0.240 g, 0.357 mmol) in dichloromethane (20 mL) was added triethylsilane (0.285 mL, 1.784 mmol) followed by trifluoroacetic acid (0.275 mL, 3.567 mmol). The reaction mixture was stirred at room temperature overnight. The reaction mixture was concentrated in vacuo and the resulting crude residue was purified by silica gel chromatography (5% MeOH/CH2Cl2) to afford the desired product: 1H NMR (400 MHz, CDCl3) δ 11.80 (s, 2H), 8.59 (d, J=12.3 Hz, 2H), 8.48 (d, J=7.9 Hz, 1H), 6.60 (d, J=8.3 Hz, 1H), 5.07 (s, 1H), 4.09 (q, J=7.0 Hz, 2H), 2.97-2.59 (m, 2H), 1.70 (dd, J=27.7, 13.9 Hz, 6H), 1.57-1.33 (m, 2H), 1.16 (dd, J=18.1, 11.1 Hz, 6H); LCMS Gradient 10-90%, 0.1% formic acid, 5 minutes, C18/ACN, Retention Time=2.97 minutes (M+H) 431.24.
