To a mixture of 3-methyl-1-[4-(7-[2-(trimethylsilyl)ethoxy]methyl-7H-pyrrolo[2,3-d]pyrimidin-4-yl)-1H-pyrazol-1-yl]cyclobutylacetonitrile (0.5 g, 0.001 mol) in acetonitrile (8.07 mL, 0.154 mol) and water (0.70 mL, 0.039 mol) was added lithium tetrafluoroborate (1.10 g, 0.0114 mol). The solution was warmed to reflux at 100° C. over 5 days. Charged 7.2 M of ammonium hydroxide in water (0.59 mL) in portions over a period of 5 minutes at rt adjusting pH to 9-10. The reaction mixture was stirred for 2 h at rt. The reaction was filtered and the filtrate was diluted with acetonitrile, water and MeOH and purified with prep. HPLC (XBridge C18 column, eluting with a gradient of acetonitrile/water containing 0.15% NH4OH) to give the first isomer with retention time 1.057 min, LCMS calculated for C1-6H17N6(M+H)+: 293.2; Found: 293.3. 1H NMR (500 MHz, CDCl3): δ 10.07(1H, br s), 8.88 (1H, s), 8.45 (1H, s), 8.34 (1H, s), 7.43 (1H, d, J=3.5 Hz), 6.85 (1H, d, J=3.5 Hz), 3.16 (2H, s), 2.77 (2H, m), 2.55 (1H, m), 2.43 (2H, m), 1.24 (3H, d, J=6.5 Hz) ppm; then the second isomer with retention time 1.107 min; LCMS calculated for C16H17N6(M+H)+: 293.2; Found: 293.3. 1H NMR (500 MHz, CDCl3): δ 10.21(1H, br s), 8.89 (1H, s), 8.61 (1H, s), 8.37 (1H, s), 7.44 (1H, d, J=3.5 Hz),6.86 (1 H, d, J =3.5 Hz), 3.07 (2H, s), 3.05 (2H, m), 2.61 (1H, m), 2.26 (2H, m), 1.25 (3H, d, J=7.0 Hz) ppm.
