Reaktion #684944

Reaktionsgleichung

2,5-Dibromohydroquinone

sodium hydroxide

dodecylbromide

→

2,5-Dibromo-4-dodecyloxy phenol

Ausbeute 60.0%

Lösungsmittel

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe reaction mixture was cooled
2. 2
   Sonstigethe precipitate formed
3. 3
   Filtrationwas filtered
4. 4
   Waschenwashed with methanol
5. 5
   SonstigeThe filtrate was evaporated
6. 6
   Sonstigeto remove the solvent
7. 7
   workup.ADDITION2 L of distilled water was added to the residue
8. 8
   workup.WAITboiled gently for 1 h
9. 9
   Temperaturcooled
10. 10
    FiltrationThe resulting precipitate was collected by filtration
11. 11
    Waschenwashed with water
12. 12
    Sonstigedried in vacuo
13. 13
    SonstigeThe crude product was purified by column chromatography
14. 14
    workup.ADDITIONa mixture of solvents (CH2Cl2:hexanes, 4:6)
15. 15
    Sonstigeto get the pure product in 60% yield

Vorschrift

2,5-Dibromohydroquinone 3 (40.2 g, 0.15 mol) was dissolved in a solution of sodium hydroxide (9.2 g, 0.23 mol) in 1.5 L of absolute ethanol at room temperature under nitrogen atmosphere. The reaction mixture was warmed to 50-60° C. with constant stirring. The dodecylbromide (36 ml, 0.15 mol) was added drop wise to the above reaction mixture at 60° C. After 10 h of stirring under nitrogen atmosphere, the reaction mixture was cooled and the precipitate formed was filtered and washed with methanol. This precipitate was identified as dialleylated-2,5-dibromohydroquinone as a side product. The filtrate was evaporated to remove the solvent. 2 L of distilled water was added to the residue and the mixture was acidified with 36% HCl, boiled gently for 1 h and cooled. The resulting precipitate was collected by filtration, washed with water and dried in vacuo. The crude product was purified by column chromatography using a mixture of solvents (CH2Cl2:hexanes, 4:6) to get the pure product in 60% yield.

Quelle