To a 5 mL conical microwave vial was added potassium phosphate (Aldrich, 129 mg, 0.61 mmol), PdCl2AmPhos (17.1 mg, 0.02 mmol), tert-butyl 1-(6-(5-bromo-1-(tetrahydro-2H-pyran-2-yl)-1H-indazol-3-yl)pyrazin-2-yl)piperidin-4-ylcarbamate (compound 1e, 135 mg, 0.24 mmol), and 2-fluoro-3-methoxyphenylboronic acid (Frontier Scientific, 45.3 mg, 0.27 mmol) which was sealed, evacuated and back-filled with N2 3×. Dioxane (2.0 mL) and water (0.4 mL) were added and the resulting mixture was heated at 150° C. for 30 min with microwave irradiation. After the reaction mixtures were filtered, the crude reaction mixture was concentrated under reduced pressure. The dark brown residue was dissolved with DMSO, filtered, and purified by HPLC (5% 0.1% TFA in water to 95% 0.1% TFA in ACN over 20 min) to give tert-butyl 1-(6-(5-(2-fluoro-3-methoxyphenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-indazol-3-yl)pyrazin-2-yl)piperidin-4-ylcarbamate (78.1 mg, 53.5%). MS (ESI, pos. ion) m/z: 603 (M+1). A mixture of 5N HCl in IPA (25.9 μL, 0.13 mmol), tert-butyl 1-(6-(5-(2-fluoro-3-methoxyphenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-indazol-3-yl)pyrazin-2-yl)piperidin-4-ylcarbamate (78.1 mg, 0.13 mmol), DCM (1.3 mL) and MeOH (1.3 mL) was heated at 80° C. for 30 min with stirring. The resulting reaction mixture was cooled to RT and concentrated to a yellow solid. The above solid was stirred with a 1:1 mixture of DCM:MeOH and applied to a pre-washed (10 mL MeOH) column of Si-propylsulfonic acid (Silicycle, Cat# R51230B). The compound was released with 30 mL of MeOH (with 2M NH3) to yield the title compound product as a yellow oil. MS (ESI, pos. ion) m/z: 419 (M+1).
