Reaktion #64038

Reaktionsgleichung

sodium hydroxide

Diethyl malonate

sodium

1-(2,4,6-trimethylphenyl)but-1-en-3-one

→

3-hydroxy-5-mesitylcyclohex-2-en-1-one

Lösungsmittel

ethanol

water

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe mixture was heated
2. 2
   Temperaturto reflux temperature
3. 3
   workup.ADDITIONwas added over a period of 2 minutes
4. 4
   Temperaturthe mixture was heated
5. 5
   Temperaturunder reflux for a period of 2 hours
6. 6
   Temperaturthe mixture was heated
7. 7
   Temperaturunder reflux for a further 41/2 hours
8. 8
   Extraktionthe aqueous mixture was extracted twice with ethyl acetate (100 ml)
9. 9
   Temperaturwarmed gently until the evolution of carbon dioxide
10. 10
    ExtraktionThe aqueous mixture was extracted with ethyl acetate
11. 11
    Trocknendried over anhydrous sodium sulfate
12. 12
    Sonstigethe solvent was removed by evaporation under reduced pressure
13. 13
    Sonstigea rotary evaporator

Vorschrift

Diethyl malonate (10.1 g; 60 mmole) was added to a solution of sodium metal (1.4 g; 60 mmole) in anhydrous absolute ethanol (50 ml) and the mixture was heated to reflux temperature. A mixture of 1-(2,4,6-trimethylphenyl)but-1-en-3-one (11.4 g; 61 mmole) in anhydrous absolute ethanol (50 ml) was added over a period of 2 minutes and the mixture was heated under reflux for a period of 2 hours. An aqueous solution of sodium hydroxide (7.3 g; 180 mmole in 100 ml of water) was added and the mixture was heated under reflux for a further 41/2 hours. The solution was poured into water (200 ml) and the aqueous mixture was extracted twice with ethyl acetate (100 ml). The aqueous phase was acidified with concentrated hydrochloric acid and warmed gently until the evolution of carbon dioxide ceased. The aqueous mixture was extracted with ethyl acetate, dried over anhydrous sodium sulfate, and the solvent was removed by evaporation under reduced pressure using a rotary evaporator. The product, 3-hydroxy-5-mesitylcyclohex-2-en-1-one, was obtained as a pale yellow solid (10.9 g; 77.4%), mp 165° C. Proton magnetic resonance spectrum (dimethylsulfoxide; δ in ppm): 2.0-4.1 (14H, m); 5.2 (1H, s); 6.8 (2H, s); 11.2 (1H, br.s).

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