Methyl iodide → 3,5-Dichloro-4-methylpyridine
反応式
[Cl:1][C:2]1[CH:3]=[N:4][CH:5]=[C:6]([Cl:8])[CH:7]=1.[Li+].[CH3:10]C([N-]C(C)C)C.IC.C(=O)([O-])O.[Na+]>C1COCC1.ClCCl>[Cl:1][C:2]1[CH:3]=[N:4][CH:5]=[C:6]([Cl:8])[C:7]=1[CH3:10][Cl:1][C:2]1[CH:3]=[N:4][CH:5]=[C:6]([Cl:8])[CH:7]=1.[Li+].[CH3:10]C([N-]C(C)C)C.IC.C(=O)([O-])O.[Na+]>C1COCC1.ClCCl>[Cl:1][C:2]1[CH:3]=[N:4][CH:5]=[C:6]([Cl:8])[C:7]=1[CH3:10]
3,5-Dichloropyridine (2.04 g, 13.5 mmol) in THF (5 ml) was added dropwise to a solution of LDA [prepared from diisopropylamine (1.9 ml, 13.5 mmol) and n-butyllithium (1.6M, 8.4 ml, 13.5 mmol)] in THF (25 ml) at -70° C. After stirring at this temperature for 5 min, iodomethane (0.85 ml, 13.5 mmol) was added and the reaction mixture stirred for a further 1.5 h at -70° C. Saturated sodium hydrogen carbonate solution (20 ml) and dichloromethane (20 ml) was added and the organic phase separated, dried (MgSO4), and concentrated in vacuo. The residue was subjected to chromatography (SiO2 ; Et2O-hexane, 1:3) to afford the title compound (1.16 g) as a pale yellow solid; δH (CDCl3) 2.46 (3H, s, Me), and 8.36 (2H, s, pyridine H2, H6).
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