N-(4-(4-(3-aminopropanoyl)piperazin-1-yl)-5-bromo-1H-pyrrolo[2,3-b]pyridin-3-yl)nicotinamide (0.060 g, 0.103 mmol, see Example 62) and acetone (0.0599 g, 1.03 mmol) were placed in 1:1 DCE:DMF (5 mL). DIEA (d 0.742; 0.0898 mL, 0.516 mmol) was then added, followed by the addition of NaBH(OAc)3 (0.0437 g, 0.206 mmol). The reaction was then stirred for 30 minutes, and poured into Na2CO3 and extracted into DCM (3×30 mL). The organic fractions were combined, dried, filtered and concentrated. The resulting residue was purified by reverse phase HPLC to give a pure product. The product was then dissolved in minimal DCM and added to a stirring solution of 1M HCl in ether (10 mL). The resulting solid was collected to give N-(5-bromo-4-(4-(3-(isopropylamino)propanoyl)piperazin-1-yl)-1H-pyrrolo[2,3-b]pyridin-3-yl)nicotinamide (0.030 g, 46.6% yield) as the trihydrochloride salt. MS APCI (+) m/z 515 detected.
