反応 #487502

反応方程式

2-methyl-1,3-cyclopentanedione

methyl iodide

KOH

dioxane

KOH

MeI

dioxane

KOH

MeI

dioxane

→

oil

収率 93.0%

2,2-Dimethyl-cyclopentane-1,3-dione

収率 93.0%

溶媒

water

water

water

反応条件

後処理

1. 1
   その他Synthesized
2. 2
   温度was heated
3. 3
   温度at reflux
4. 4
   温度at reflux
5. 5
   温度heating
6. 6
   温度at reflux
7. 7
   workup.WAITAfter 4 hours
8. 8
   温度the mixture was cooled to room temperature
9. 9
   抽出extracted with ether (1×100 mL, 3×75 mL)
10. 10
    その他The combined ether extracts were evaporated
11. 11
    その他placed in a 120° C.
12. 12
    その他(ca. 15 minutes)
13. 13
    温度The mixture was cooled to room temperature
14. 14
    workup.ADDITIONneutralized by addition of saturated NaHCO3 solution (150 mL)
15. 15
    抽出the resulting mixture extracted with CH2Cl2 (4×75 mL)
16. 16
    乾燥The combined CH2Cl2 solution was dried (MgSO4)
17. 17
    ろ過filtered
18. 18
    その他evaporated

実験手順

Synthesized according to Agosta and Smith, J. Org. Chem. 35: 3856 (1970) A mixture of 2-methyl-1,3-cyclopentanedione (10.025 g, 89.4 mmol, Aldrich), methyl iodide (6.0 mL, 96.4 mmol, Aldrich), and KOH (5.097 g, 90.8 mmol) in water (25 mL)/dioxane (75 mL) was heated at reflux. After 5 hours, a solution of KOH (2 g) and MeI (2.4 mL) in water (5 mL)/dioxane (15 mL) was added and after another 3 hours at reflux, the solution was stirred at room temperature overnight. A solution of KOH (2 g) and MeI (2.4 mL) in water (5 mL)/dioxane (15 mL) was added to the overnight reaction and heating at reflux. After 4 hours, the mixture was cooled to room temperature and extracted with ether (1×100 mL, 3×75 mL). The combined ether extracts were evaporated, the residue combined with 10% HCl (50 mL), and the resulting mixture placed in a 120° C. oil bath until it began boiling (ca. 15 minutes). The mixture was cooled to room temperature, neutralized by addition of saturated NaHCO3 solution (150 mL) and the resulting mixture extracted with CH2Cl2 (4×75 mL). The combined CH2Cl2 solution was dried (MgSO4), filtered and evaporated to leave a brown oil (10.474 g, 83 mmol, 93%) which was used directly in the next step.

出典