A solution of oxone (1.9 g, 3.1 mmol), trifluoroacetic anhydride (1.1 ml, 7.9 mmol) and H2O (5.7 ml) was stirred at 40° C. for 7 h, and then cooled to room temperature. To this a solution of tert-butyl 4-(6-acetyl-7-(bis((2-(trimethylsilyl)ethoxy)methyl)amino)-3-(6-phenylpyridin-3-yl)pyrazolo[1,5-a]pyrimidin-5-yl)piperidine-1-carboxylate (0.87 g, 1.13 mmol) and PhI (0.03 ml, 0.23 mmol) in acetonitrile (17 ml) was added. The resulting solution was stirred at 90° C. for 15 h. On cooling, the reaction mixture was filtered and solids were washed with DCM. It was then concentrated in vacuo to give a crude product which was submitted to the analytical group for purification to afford the desired 1-(7-amino-3-(6-phenylpyridin-3-yl)-5-(piperidin-4-yl)pyrazolo[1,5-a]pyrimidin-6-yl)-2-hydroxyethanone (94.2 mg, 17%).
