反应详情

N,N-diisopropylamine (65.6 ml) was dissolved in anhydrous THF (150 ml), to which was dropwise added n-butyl lithium (1.54 mols/liter hexane solution, 300 ml) in an argon atmosphere at −78° C., and directly stirred for 5 minutes. An anhydrous THF (600 ml) solution of 3,5-dichloropyridine (63 g) was dropwise added there to and stirred for 1 hours, and thereafter methyl iodide (29.2 ml) was dropwise added thereto and further stirred for 1.5 hours. Water was added to the reaction mixture to stop the reaction, which was then extracted with ethyl acetate. The extract was washed with a saturated saline solution, then dried over magnesium sulfate, and distilled under reduced pressure. This was purified by silica gel column chromatography (hexane:ethyl acetate=10:1), and the resulting residue was suspended in ether, and taken out therefrom through filtration to obtain 3,5-dichloropicoline (Compound IIbz-b, 62.8 g, 91%) as colorless crystals.

1. customat −78° C.
2. stirringstirred for 1 hours
3. stirringfurther stirred for 1.5 hours
4. customthe reaction, which
5. extractionwas then extracted with ethyl acetate
6. washThe extract was washed with a saturated saline solution
7. dry with materialdried over magnesium sulfate
8. distillationdistilled under reduced pressure
9. customThis was purified by silica gel column chromatography (hexane:ethyl acetate=10:1)
10. filtrationthrough filtration