To a cloudy mixture of 4-(1-ethyl-4-{2-[4-(1-pyrrolidinylmethyl)phenyl]-1H-pyrrolo[2,3-b]pyridin-4-yl}-1H-pyrazol-3-yl)aniline (350 mg, 0.76 mmol) in dry THF (8 mL) was added 4-nitrophenyl chloroformate (168 mg, 0.83 mmol). The resultant slurry was stirred at room temperature for 45 min and diethylamine (0.32 mL, 3.03 mmol) was added. After 1 h, the reaction was concentrated under reduced pressure and diluted with 1N NaOH and EtOAc. The aqueous layer was extracted with three portions of EtOAc followed by 5% MeOH in EtOAc and the combined extracts were dried (Na2SO4), filtered and concentrated under reduced pressure. The residue was purified by Gilson reverse phase HPLC (MeCN/H2O with 0.1% TFA) to provide 159 mg (32%) of the title product as a bis-TFA salt (yellow solid). ESMS [M+H]+: 562.4
