Hydrochloric Acid → (2,3-Dimethylpyridin-4-YL)methanamine
反応式
[BH4-].[Na+].[C:3]([C:5]1[CH:10]=[CH:9][N:8]=[C:7]([CH3:11])[C:6]=1[CH3:12])#[N:4].O.Cl>C1COCC1>[NH2:4][CH2:3][C:5]1[CH:10]=[CH:9][N:8]=[C:7]([CH3:11])[C:6]=1[CH3:12][BH4-].[Na+].[C:3]([C:5]1[CH:10]=[CH:9][N:8]=[C:7]([CH3:11])[C:6]=1[CH3:12])#[N:4].O.Cl>C1COCC1>[NH2:4][CH2:3][C:5]1[CH:10]=[CH:9][N:8]=[C:7]([CH3:11])[C:6]=1[CH3:12]To a solution of NaBH4 (65 g, 0.28 mol) in THF (150 ml) was added dropwise BF3-diethyletherate (119.2 g, 0.84 mol) at 0° C. The reaction mixture was stirred for 20 minutes at 23° C. before adding dropwise a solution of 4-cyano-2,3-dimethylpyridine (18.5 g, 0.14 mol, prepared according to J. Heterocycl. Chem. 27 (6), 1990, 1751) in THF (100 ml). The resulting reaction mixture was refluxed for 6 h. Subsequently the reaction mixture was slowly hydrolyzed with water (200 ml) and the pH-value was adjusted to pH 2 with aqueous hydrochloric acid (10% strength). The resulting reaction mixture was refluxed for another 2 hours. Subsequently the reaction mixture was poured onto water and extracted with MTBE. The aqueous layer was adjusted to pH 14 with an aqueous sodium hydroxide solution (50% strength) and extracted once more with DCM. The combined organic layers were dried and the solvent was removed in vacuo. The residue was purified by column chromatography (SiO2, MTBE) to yield 4-(aminomethyl)-2,3-dimethylpyridine as an oily substance (16.5 g). 1H-NMR (CDCl3): δ=1.7 (s, 2H), 2.3 (s, 3H), 2.5 (s, 3H), 3.9 (s, 2H), 7.15 (d, 1H) and 8.3 ppm (d, 2H).
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