A suspension of 2-((6-(1-methyl-1H-pyrazol-4-ylamino)-1H-pyrazolo[3,4-d]pyrimidin-1-yl)methyl)benzonitrile (see Example 1) (40 mg, 0.24 mmol), sodium hydroxide (0.5 mL, 1M in H2O) and hydrogen peroxide (0.2 mL of a 33% solution in water) in ethanol (5 mL) was heated at 60° C. for 3 h. After cooling to rt the mixture was diluted with EtOAc and washed with water. The organic phase was collected, dried (MgSO4) and concentrated in vacuo to give the title product. 1H NMR (d6-DMSO) δ 9.95 (s, 1H), 8.99 (s, 1H), 8.10-8.16 (m, 3H), 7.66 (s, 1H), 7.60 (dd, 1H), 7.54 (s, 1H), 7.37-7.40 (m, 2H), 6.95 (br s, 1H), 5.85 (s, 2H), 3.88 (s, 3H); LC-MS method B, (ES+) 349.1, RT=6.46 min.
