Formaldehyde (0.0712 mL, 0.957 mmol) and NaCNBH3 (0.0120 g, 0.191 mmol) were added to (S)-2-(4-chlorophenyl)-3-(isopropylamino)-1-(4-(5-phenyl-1H-pyrrolo[2,3-b]pyridin-4-yl)piperazin-1-yl)propan-1-one (0.055 g, 0.096 mmol, see Example 13) in MeOH (0.5 mL). The mixture was stirred at room temperature for 20 minutes. Saturated NaHCO3 (5 mL) was added, the aqueous layer was extracted with DCM (20 mL), and the combined organic phases were dried over sodium sulfate. After removal of the solvent, the residue was purified by chromatography (20:1:0.1 DCM:ethyl acetate:ammonium hydroxide) to give (S)-2-(4-chlorophenyl)-3-(isopropyl(methyl)amino)-1-(4-(5-phenyl-1H-pyrrolo[2,3-b]pyridin-4-yl)piperazin-1-yl)propan-1-one (0.013 g, 23%) as a solid. MS ESI (+) m/z 516 detected.
