Tert-butyl (3R)-3-aminopiperidine-1-carboxylate (1.49 g, 7.46 mmol) was added to a stirred solution of 3-(4-hydroxypyrimidin-2-yl)pyrazolo[1,5-a]pyridine-5-carbonitrile (Preparation 3b, 0.70 g, 2.98 mmol), (benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (1.71 g, 3.88 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (0.67 mL g, 4.48 mmol) in N,N′-dimethylformamide (15 mL) and the resulting mixture was stirred at room temperature for 16 hours. Then the solvent was removed under reduced pressure and the residue was taken up in a mixture of dichloromethane and 4% aqueous sodium hydrogencarbonate solution. The organic layer was separated, dried (MgSO4) and evaporated in vacuo. The crude product was purified by flash chromatography (99:1 dichloromethane/methanol) to give a residue that was repurified by reverse phase chromatography (C-18 silica from Waters, water/acetonitrile/methanol as eluents [0.1% v/v formic acid buffered] 0% to 100%) to give the title compound (0.83 g, 66%) and 3-(4-(1H-benzo[d][1,2,3]triazol-1-yloxy) pyrimidin-2-yl)pyrazolo[1,5-a]pyridine-5-carbonitrile (0.10 g) as the main reaction byproduct.
