Ponatinib monohydrochloride (501 mg, 0.88 mmol) was weighed into a round bottom flask, to which was added acetonitrile (5.0 mL) and formic acid (0.35 mL). The resulting suspension was placed in an oil bath at 50 °C. After stirring for 1 h, water (0.50 mL) was added. Immediate dissolution was observed, the resulting yellow solution was filtered while hot, and subsequently allowed to cool to room temperature (RT) over a 1.5 h period. Precipitation was observed after 2 h at RT. The suspension was stirred for an additional 16 h. The solids were collected by filtration, washed with cold acetonitrile (2.0 mL), and dried in a vacuum oven at RT to give pon·HCl as a yellow solid (248 mg, 50% yield).