To a solution of N-(3-((4-((3-aminopropyl)amino)-5-bromo-2-pyrimidinyl)amino)phenyl)-1-pyrrolidinecarboxamide (150 mg, 0.30 mmol) in dichloromethane (4 mL) was added DIEA (0.16 mL, 0.92 mmol) and DMAP (1.4 mg, 0.011 mmol) at 0° C., then a solution of 1-propanesulfonyl chloride (51 mg, 0.36 mmol) in dichloromethane (5 mL) was added. The resulting reaction mixture was stirred at 0° C. for 1 h and at room temperature overnight. The reaction mixture was concentrated. Purification by HPLC using acetonitrile/water gave the title compound (67 mg).
