[Cl:1][C:2]1[C:18]([F:19])=[CH:17][C:5]([C:6]([NH:8][C:9]2[CH:14]=[CH:13][N:12]=[C:11]([O:15]C)[CH:10]=2)=[O:7])=[C:4]([F:20])[CH:3]=1.Br.O>CC(O)=O>[Cl:1][C:2]1[C:18]([F:19])=[CH:17][C:5]([C:6]([NH:8][C:9]2[CH:14]=[CH:13][NH:12][C:11](=[O:15])[CH:10]=2)=[O:7])=[C:4]([F:20])[CH:3]=1To 4-chloro-2,5-difluoro-N-(2-methoxy-4-pyridyl)benzamide (3 g, 10.04 mmol) in HOAc (15.9 mL) was added HBr 33% in HOAc (12.31 mL of 33% w/v, 50.20 mmol) and the mixture was stirred at 90° C. for 5 h. Additional HBr (10 mL, 33% in HOAc) was added and the mixture was stirred at 90° C. overnight. The mixture was cooled to room temperature and was poured into water (100 mL). The mixture was stirred and the solid was collected by filtration. The solid was washed with water (2×50 mL). The solid was slurried in hexanes (2×50 mL) and filtered to give 4-chloro-2,5-difluoro-N-(2-oxo-1H-pyridin-4-yl)benzamide (969.7 mg, 34%) as a cream colored solid. ESI-MS m/z calc. 284.02. found 285.3 (M+1)+; Retention time: 1.36 minutes (3 min run).
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