反应详情

To a solution of 4,4-dimethyl-3-oxopentanenitrile (0.626 g, 5.0 mmol) in dry acetone (10 ml) first potassium carbonate (1.38 g, 10 mmol) and then 3,4-methylendioxyphenyl isothiocyanate (0.941 g, 5.3 mmol) were added. The resulting mixture was stirred at room temperature under nitrogen for 72 h, and then filtered. To the filtrate methyl iodide (0.93 ml, 15 mmol) was added. The mixture was stirred at room temperature for 45 min. The precipitate was filtered off and the filtrate was concentrated. The residue was taken up into dichloromethane and water. The organic layer was washed with water (2×), dried (sodium sulfate) and concentrated. Crystallisation from ethyl acetate/heptane 1:1 gave 1.56 g (98%) of the title compound. Mp 139-141° C.; 1H NMR (200 MHz, CDCl3): δ=1.40 (s, 9H), 2.28 (s, 3H), 6.03 (s, 2H), 6.75 (dd, 1H), 6.8 (m, 2H), 13.5 (br s, 1H); EI SP/MS: 318 (M+).

1. filtrationfiltered
2. stirringThe mixture was stirred at room temperature for 45 min
3. filtrationThe precipitate was filtered off
4. concentrationthe filtrate was concentrated
5. washThe organic layer was washed with water (2×)
6. dry with materialdried (sodium sulfate)
7. concentrationconcentrated
8. customCrystallisation from ethyl acetate/heptane 1:1