[N+:1]([C:4]1[CH:5]=[C:6]([C:11]([F:14])([F:13])[F:12])[C:7](=O)[NH:8][CH:9]=1)([O-:3])=[O:2].P(Br)(Br)([Br:17])=O.P(Br)(Br)Br.BrBr>>[Br:17][C:7]1[C:6]([C:11]([F:14])([F:13])[F:12])=[CH:5][C:4]([N+:1]([O-:3])=[O:2])=[CH:9][N:8]=1A mixture of 5-nitro-3-(trifluoromethyl)pyridin-2(1H)-one 3, POBr3 (1.5 equivalents), PBr3 (4 equivalents), and Br2 (2 equivalents) is heated to about 90-110° C. and is then poured into ice water. The mixture is neutralized and extracted. The combined organic phases are dried over Na2SO4 and all solvents removed under reduced pressure to obtain 2-bromo-5-nitro-3-(trifluoromethyl)pyridine 21 in a yield of 88%.
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