tert-Butyl {(3S)-1-[3-({[2-(2,6-difluorophenyl)-1,3-thiazol-4-yl]carbonyl}amino)-6,7-dihydro-5H-cyclopenta[b]pyridin-4-yl]piperidin-3-yl}carbamate (4 mg, 0.007 mmol) was dissolved in DCM (0.02 mL) and then TFA (0.03 mL, 0.4 mmol) was added. The resulting reaction mixture was stirred at room temperature for 30 min. and then concentrated to give a residue, which was diluted with MeOH and neutralized with small amount of NH4OH. The mixture was filtered and purified by preparative LC-MS (XBridge™ preparative C18 30×10 mm, 5 m OBD™ column, at flow rate of 60 mL/min., eluting with a gradient of MeCN and water with 0.15% NH4OH) to afford the title compound (1.9 mg, 58%). LCMS calc. for C23H24F2N5OS (M+H)+: m/z=456.2. Found: 456.1.
