反应详情

Diethyl malonate (6.50 ml, 43 mmol) is added dropwise to a cooled (ice-bath) solution of sodium (1.07 g, 46 mmol) in anhydrous ethanol (60 ml) and once the addition is complete the cooling bath is removed and the reaction mixture is stirred at room temperature for 25 minutes. The mixture is cooled in an ice bath and a solution of 4-(tetrahydrofuran-3-yl)-3-buten-2-one (5.0 g, 36 mmol) in ethanol (30 ml) is added dropwise. Once the addition is complete the cooling bath is removed and the reaction mixture is stirred at room temperature for 19 hours. The reaction mixture is acidified to pH 3 by dropwise addition of 2M aqueous hydrochloric acid, water added to dissolve any precipitate formed and the reaction mixture is extracted into dichloromethane. The organic extracts are dried over anhydrous magnesium sulphate, filtered and the filtrate is concentrated in vacuo to afford a yellow oil which is taken up in isopropanol (35 ml) and a 2M aqueous solution of sodium hydroxide (100 ml) is added. The reaction mixture is stirred at room temperature for 20 hours. The reaction mixture is concentrated in vacuo to remove isopropanol then heated to 70° C. A solution of 2M aqueous hydrochloric acid is added carefully until the reaction mixture reached pH 1. The reaction mixture is heated for 1½ hours at 70° C., then cooled to room temperature, diluted with water and the product is extracted into ethyl acetate. The organic extracts are combined, dried over anhydrous magnesium sulphate, filtered and the filtrate is concentrated in vacuo to give 5-(tetrahydrofuran-3-yl)cyclohexane-1,3-dione as a yellow solid.

1. additiononce the addition
2. customis removed
3. temperatureThe mixture is cooled in an ice bath
4. additionOnce the addition
5. customis removed
6. stirringthe reaction mixture is stirred at room temperature for 19 hours
7. additionThe reaction mixture is acidified to pH 3 by dropwise addition of 2M aqueous hydrochloric acid, water
8. additionadded
9. dissolutionto dissolve any precipitate
10. customformed
11. extractionthe reaction mixture is extracted into dichloromethane
12. dry with materialThe organic extracts are dried over anhydrous magnesium sulphate
13. filtrationfiltered
14. concentrationthe filtrate is concentrated in vacuo
15. customto afford a yellow oil which
16. stirringThe reaction mixture is stirred at room temperature for 20 hours
17. concentrationThe reaction mixture is concentrated in vacuo
18. customto remove isopropanol
19. temperaturethen heated to 70° C
20. additionA solution of 2M aqueous hydrochloric acid is added carefully until the reaction mixture
21. temperatureThe reaction mixture is heated for 1½ hours at 70° C.
22. temperaturecooled to room temperature
23. additiondiluted with water
24. extractionthe product is extracted into ethyl acetate
25. dry with materialdried over anhydrous magnesium sulphate
26. filtrationfiltered
27. concentrationthe filtrate is concentrated in vacuo