Reaktion #7564

Reaktionsgleichung

boron tribromide

2,4-dimethoxytoluene

ethyl acetate

sodium hydroxide

→

2,4-dihydroxytoluene

Ausbeute 94.1%

Lösungsmittel

pentane

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe starting material 2,4-dihydroxytoluene was prepared
2. 2
   workup.STIRRINGAfter stirring for 10 minutes
3. 3
   Sonstigethe organic layer was separated
4. 4
   Extraktionthe aqueous layer extracted with ethyl acetate
5. 5
   ExtraktionThe combined organic extract
6. 6
   Waschenwas washed with brine
7. 7
   Trocknendried (MgSO4)
8. 8
   Sonstigethe solvent removed by evaporation
9. 9
   SonstigeThe residue was purified by flash chromatography
10. 10
    Wascheneluting with methylene chloride/ethyl acetate (9/1)

Vorschrift

The starting material 2,4-dihydroxytoluene was prepared by adding boron tribromide (3.1 ml, 3.2 mmol) to a solution of 2,4-dimethoxytoluene (1 g, 6.5 mmol) in pentane (10 ml) at −70° C. The reaction mixture was allowed to warm to ambient temperature and the mixture stirred for a further 2 hours. Ice water and ethyl acetate were then added and the aqueous layer basified to pH9.5 with 2M aqueous sodium hydroxide solution. After stirring for 10 minutes, the organic layer was separated and the aqueous layer extracted with ethyl acetate. The combined organic extract was washed with brine, dried (MgSO4) and the solvent removed by evaporation. The residue was purified by flash chromatography eluting with methylene chloride/ethyl acetate (9/1) to give 2,4-dihydroxytoluene (759 mg, 94%) as a white solid.

Quelle