To a solution of 2-(4-(3-fluorophenyl)-7-methoxy-1-oxophthalazin-2(1H)-yl)-N-methyl-N-(2-methylbenzo[d]oxazol-6-yl)acetamide (example 70) (4.0 g, 8.469 mmol) in DCM (30 mL) was added BBr3 (4.8 mL, 50.8 mmol) at 0° C. The reaction mixture was stirred at rt overnight then diluted with water (150 mL), neutralized with NaHCO3, then extracted with DCM (3×100 mL). The organic layer was washed with brine (100 mL), dried over Na2SO4, and concentrated to yield 2-(4-(3-fluorophenyl)-7-hydroxy-1-oxophthalazin-2(1H)-yl)-N-methyl-N-(2-methylbenzo[d]oxazol-6-yl)acetamide (2.9 g, 74%) (459.36 [M+H]).
