[Br:1][C:2]1[CH:3]=[C:4]([O:12]C)[C:5]([C:8]([F:11])([F:10])[F:9])=[N:6][CH:7]=1.O.O.O.O.C(C(C(C([O-])=O)O)O)([O-])=O.[Na+].[K+]>C(O)(=O)C.Br.C(OCC)(=O)C>[Br:1][C:2]1[CH:3]=[C:4]([OH:12])[C:5]([C:8]([F:9])([F:10])[F:11])=[N:6][CH:7]=1A solution of 5-bromo-3-methoxy-2-(trifluoromethyl)pyridine (28) (0.87 g, 3.4 mmol) in a mixture of acetic acid (6 mL) and 33% HBr in acetic acid (12 mL) was stirred at 110° C. in a sealed tube overnight. Then Potassium Sodium tartrate tetrahydrate (7.8 g) was added slowly under 0° C. The mixture was taken up in ethyl acetate after 10 minutes stirring, the organic phase was washed with brine, dried over Na2SO4. The extract was concentrated under reduced pressure. The residue was purified by column chromatography on silica gel using a gradient of Hexane-Ethyl acetate (1:2) as the eluent to give the product (29) 0.65 g as gray solid, Yield: 79%. 1H NMR (CD3OD, 400 MHz): δ 8.18 (s, 1H), 7.58 (s, 1H). 19F NMR (CDCl3, 376 MHz): −68.0.
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