In a 250 mL round-bottomed flask, 2-(6-aminopyridin-3-ylthio)ethanol (247 mg, 1.45 mmol), 2-(5-bromo-1-methyl-6-oxo-1,6-dihydropyridazin-3-yl)-6-(6-tert-butyl-8-fluoro-1-oxophthalazin-2(1H)-yl)benzyl acetate (806 mg, 1.45 mmol), xantphos (126 mg, 218 μmol) and Cs2CO3 (1.42 g, 4.35 mmol) were combined with dioxane (20 ml) to give a brown suspension. The reaction was evacuated and filled with argon. Pd2(dba)3 (66.4 mg, 72.5 μmol) was added and the reaction mixture was heated to 100° C. and stirred for 17 h under argon. Cooled to 25° C. and diluted with DCM. The reaction mixture was filtered over celite and the filter cake was washed with DCM until clear. The filtrate was conc. in vacuo. The crude material was purified by flash chromatography (silica gel, 40 g, 0% to 3% MeOH in DCM). The material was repurified by flash chromatography (silica gel, 40 g, 0% to 50% Acetone in Heptane), concentrated in vacuo to a white powder and dried under vacuum at 25° C. overnight. The product was taken up in dioxane (15 ml) and 1M LiOH (3 ml) was added. The reaction was stirred at 25° C. for 17 hrs. The crude reaction mixture was concentrated in vacuo. The residue was diluted with 15 mL DCM and 15 mL H2O. The aqueous layer was back-extracted with DCM (2×20 mL). The organic layers were dried over Na2SO4 and concentrated in vacuo. The crude material was purified by flash chromatography (silica gel, 40 g, 0% to 50% acetone in heptane) to afford 0.061 g (7%) of the title compound as a white powder. (M+H)+=603 m/e.
