A mixture of benzyl trans-4-(5′-chloro-6-((S)-piperidin-3-yl-methylamino)-2,4′-bipyridin-2′-yl-amino)cyclohexylcarbamate (15 mg, 0.027 mmol), DCM (2 mL), TEA (0.011 mL, 0.082 mmol) and acetic anhydride (3.09 μL, 0.033 mmol) was stirred at ambient temperature for 2 hours and the reaction progress was followed by LCMS. The solvent was concentrated off. The reaction mixture flask was flushed with argon, 10% palladium on activated carbon (5 mg, 4.70 μmol) was added and followed by careful addition of MeOH (0.8 mL). The resulting mixture was stirred under hydrogen for 45 minutes at ambient temperature and monitored by LCMS. To the crude reaction mixture was added 2 ml of DCM, filtered and the solvent was concentrated off. The resulting residue was dissolved in 1.0 ml of DMSO, filtered and purified by prep HPLC to give two fractions corresponding to the two title compounds respectively. After lyophilization, 4.0 mg of 1-((R)-3-((2′-(trans-4-aminocyclohexylamino)-5′-chloro-2,4′-bipyridin-6-yl-amino)methyl)piperidin-1-yl)ethanone, was obtained as a TFA salt. LCMS (m/z): 457.2 (MH+), retention time=0.46 min. In addition, 1.0 mg of 1-((R)-3-((2′-(trans-4-aminocyclohexylamino)-2,4′-bipyridin-6-yl-amino)methyl)piperidin-1-yl)ethanone, as TFA salt was also obtained. LCMS (m/z): 423.2 (MH+), retention time=0.45 min. This reaction yielded two products which are separated and purified by HPLC.
