[BrH:1].[C:2]([C:4]([S:10][C:11]([F:14])([F:13])[F:12])=[CH:5][CH:6]=[CH:7]OC)#[N:3].C([O-])([O-])=O.[Na+].[Na+]>CC(O)=O>[Br:1][C:2]1[C:4]([S:10][C:11]([F:14])([F:13])[F:12])=[CH:5][CH:6]=[CH:7][N:3]=1A solution of 30% HBr, AcOH (70 mL) was added dropwise with stirring at 40° C. to a solution of 4-cyano-4-trifluoromethylthio-3-butenealdehydedimethylacetal and 1-cyano-1-trifluoromethylthio-4-methoxy-1,3-butadiene (8.8 g) in AcOH (40 mL). After the addition, the solution was heated at 55° C. for 2 hours, poured onto ice and neutralized with solid Na2CO3. The solution was extracted with CH2Cl2 (3-) and the CH2Cl2 extracts dried, filtered and concentrated to dryness. The residual oil was distilled at 68°-71° C. at 0.3 mm of yield 4.0 g (16%) of 2-bromo-3-trifluoromethylthiopyridine 1H NMR (CDCL3) δ 7.35 (1H, dd, J=4 and 8), 8.05 (1H, dd, J=2 and 8), 8.45 (1H, dd, J=3 and 4); 19F NFR (CDCl3) +40.7 (s).
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