反応 #55676

反応方程式

methylacetoacetate

sodium ethoxide

chloride

→

Sodiomethylacetoacetate

溶媒

ethanol

反応条件

後処理

1. 1
   その他at 25°
2. 2
   温度The reaction mixture was cooled to 0°
3. 3
   workup.ADDITIONabove was added dropwise over a 25-minute period
4. 4
   workup.WAITAfter this period
5. 5
   workup.WAITto ambient over a 40-minute period
6. 6
   workup.DISTILLATIONA portion of the ethanol (78.0 g) was distilled at this point
7. 7
   workup.STIRRINGby stirring the reaction mixture at 60°-65° for 2 hours under a slight vacuum
8. 8
   温度After cooling to 30°
9. 9
   workup.ADDITIONof 10% aqueous NaOH was added over a 15-minute period
10. 10
    workup.STIRRINGthe reaction mixture was stirred at 70° for 4 hours
11. 11
    その他the layers were separated
12. 12
    抽出extracted with three 200-ml
13. 13
    洗浄The combined oils were washed once with 1 liter H2O and once with 1 liter saturated NaCl
14. 14
    その他to yield
15. 15
    その他after solvent removal, 139.2 g of crude 6,10,14-trimethylpentadeca-5,9-dien-2-one
16. 16
    その他yield from 10,11-dihydrofarnesene of 78.8%

実験手順

Sodiomethylacetoacetate was prepared by adding an excess of methylacetoacetate (74.3 g, 0.64 mole) to a solution of sodium ethoxide (31.3 g, 0.46 mole) in 150 mls. absolute ethanol at 25°. The reaction mixture was cooled to 0° and then the crude chloride prepared above was added dropwise over a 25-minute period and stirring was continued at 0° for an additional 3 hours. After this period, the temperature was allowed to rise to ambient over a 40-minute period. A portion of the ethanol (78.0 g) was distilled at this point by stirring the reaction mixture at 60°-65° for 2 hours under a slight vacuum. After cooling to 30°, 550 mls. of 10% aqueous NaOH was added over a 15-minute period and the reaction mixture was stirred at 70° for 4 hours. After settling, the layers were separated and the aqueous layer was saturated with NaCl and extracted with three 200-ml. portions of pentane. The combined oils were washed once with 1 liter H2O and once with 1 liter saturated NaCl to yield, after solvent removal, 139.2 g of crude 6,10,14-trimethylpentadeca-5,9-dien-2-one. Gas chromotographic analysis indicated 53.2% purity which represents an estimated theory yield from 10,11-dihydrofarnesene of 78.8%.

出典