反应详情

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrobromide (110.0 g, 0.434 mole, described in Example 3) is dissolved in water (1250 ml). A solution of sodium bromide (128.0 g, 1.24 moles) and bromine (70.0 g, 0.440 mole) in water (1000 ml) is added dropwise with stirring to the above solution over a period of 1 hour. The mixture is concentrated under reduced pressure to half its original volume. The precipitate is isolated by filtration and recrystallized from glacial acetic acid to give the title compound as the hydrobromide salt, mp 191°-192° C. (R. E. Lyle and W. E. Krueger, supra, reported mp 195°-197° C.).

1. concentrationThe mixture is concentrated under reduced pressure to half its original volume
2. customThe precipitate is isolated by filtration
3. customrecrystallized from glacial acetic acid