The solids are collected by filtration and washed with a mixture of purified water (210 kg, 1.5 X) and IPA (34 kg, 0.24 X) followed by purified water (182 kg, 1.3 X), then reslurried with purified water (182 kg, 1.3 X) until the pH of the filter cake is not more than 8.3. The crude MRTX849 is then dried under vacuum to a KF endpoint of not more than 1% w/w.