Reacción #487563

Ecuación de reacción

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

Rendimiento 46.6%

Disolventes

dichloromethane

toluene

chloroform

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturato cool to room temperature overnight
2. 2
   Filtraciónthe mixture is filtered through diatomaceous earth
3. 3
   Lavadowashing through with more dichloromethane (250 ml)
4. 4
   OtroThe two layers are separated
5. 5
   Extracciónthe aqueous phase is extracted with dichloromethane (500 ml)
6. 6
   Lavadowashed with 2M aqueous hydrochloric acid (1000 ml)
7. 7
   Secadobrine (1000 ml), dried over anhydrous magnesium sulfate
8. 8
   Filtraciónfiltered
9. 9
   Otrothe filtrate is evaporated under reduced pressure
10. 10
    OtroThe residue is purified by preparative normal phase chromatography

Procedimiento

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).

Fuente