A solution of 6-chloro-3,5-dimethylpyrazine-2-carboxamide (Intermediate A) (228 mg, 1.23 mmol) and methyl 2-(2-chloro-2′,6′-difluoro-4′-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)biphenyl-4-yl)acetate (Intermediate 2-2; 521 mg, 1.23 mmol) and potassium phosphate, tri-basic (314 mg, 1.48 mmol) in DME (15 mL), MeOH (3.75 mL) and water (3.75 mL) was thoughroughly degassed. The mixture was treated with PdCl2(dppf)-DCM adduct (50.3 mg, 0.06 mmol), degassed again and the atmosphere replaced with nitrogen before being heated to 80° C. for 17 hours. The reaction mixture was allowed to cool to room temperature and then evaporated. The crude product was partitioned between EtOAc (75 mL), and 2M HCl (50 mL), the aqueous phase was extracted with a further 80 mL of EtOAc. The organic extracts were combined, dried over MgSO4, filtered and evaporated to afford crude product. The crude product was purified by flash silica chromatography, elution gradient 10 to 70% EtOAc in isohexane. Pure fractions were evaporated to dryness to afford methyl 2-(4′-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2′,6′-difluorobiphenyl-4-yl)acetate (295 mg, 53.7%) as a white solid.
