反应详情

温度

-50 °C

To a stirred solution of 46.1 ml of diisopropylamine in 100 ml of tetrahydrofuran at 0°-5° C. was added 126 ml of 2.6M n-butyllithium in hexane over a period of about 20 minutes. The mixture was cooled to -50° C., 31.95 g of 3,5-dimethylisoxazole was added and the mixture stirred for 30 minutes. The latter mixture was cooled to -78° C. and 101.6 ml of 1,6-dibromohexane was added dropwise. After the addition was complete, the temperature of the reaction mixture was allowed to rise to room temperature and kept there for about 40 hours. Saturated aqueous ammonium chloride solution was then added and the mixture extracted with ethyl acetate. The ethyl acetate extracts were dried over anhydrous magnesium sulfate and concentrated in vacuo. The residue was distilled to remove excess dibromide (b.p. 50° C., 0.5 mm) and suspended in hexane. The suspension was decolorized with charcoal, filtered and cooled in a refrigerator overnight. The mixture was filtered and the filtrate concentrated in vacuo to give 57 g of 5-(7-bromoheptyl)-3-methylisoxazole as a colorless oil.

1. temperatureThe latter mixture was cooled to -78° C.
2. additionAfter the addition
3. customto rise to room temperature
4. waitkept there for about 40 hours
5. extractionthe mixture extracted with ethyl acetate
6. dry with materialThe ethyl acetate extracts were dried over anhydrous magnesium sulfate
7. concentrationconcentrated in vacuo
8. distillationThe residue was distilled
9. customto remove excess dibromide (b.p. 50° C., 0.5 mm)
10. filtrationfiltered
11. temperaturecooled in a refrigerator overnight
12. filtrationThe mixture was filtered
13. concentrationthe filtrate concentrated in vacuo