反応 #487563

反応方程式

4,4-dimethylcyclohexane-1,3-dione

5-bromo-2-ethylphenyl lead triacetate

dimethylaminopyridine

hydrochloric acid

→

2-(5-bromo-2-ethylphenyl)-4,4-dimethylcyclohexane-1,3-dione

収率 46.6%

溶媒

dichloromethane

toluene

chloroform

反応条件

後処理

1. 1
   温度to cool to room temperature overnight
2. 2
   ろ過the mixture is filtered through diatomaceous earth
3. 3
   洗浄washing through with more dichloromethane (250 ml)
4. 4
   その他The two layers are separated
5. 5
   抽出the aqueous phase is extracted with dichloromethane (500 ml)
6. 6
   洗浄washed with 2M aqueous hydrochloric acid (1000 ml)
7. 7
   乾燥brine (1000 ml), dried over anhydrous magnesium sulfate
8. 8
   ろ過filtered
9. 9
   その他the filtrate is evaporated under reduced pressure
10. 10
    その他The residue is purified by preparative normal phase chromatography

実験手順

To a mixture of 4,4-dimethylcyclohexane-1,3-dione (6.28 g, 45 mmol), 5-bromo-2-ethylphenyl lead triacetate (28 g, 49 mmol) and dimethylaminopyridine (27.4 g, 0.22 mol) under nitrogen are added anhydrous chloroform (300 ml) and toluene (75 ml). The reaction mixture is heated at 80° C. for 2 hours and then allowed to cool to room temperature overnight. 2M Aqueous hydrochloric acid (750 ml) and dichloromethane (500 ml) are added and the mixture is filtered through diatomaceous earth, washing through with more dichloromethane (250 ml). The two layers are separated and the aqueous phase is extracted with dichloromethane (500 ml). The organic layers are combined and washed with 2M aqueous hydrochloric acid (1000 ml) and then brine (1000 ml), dried over anhydrous magnesium sulfate, filtered and the filtrate is evaporated under reduced pressure. The residue is purified by preparative normal phase chromatography to give 2-(5-bromo-2-ethylphenyl)-4,4-dimethylcyclohexane-1,3-dione (6.78 g).

出典