Reaktion #59776

Reaktionsgleichung

2-hydroxy-5-bromo-phenylacetic acid

potassium tert.butoxide

benzylbromide

→

2-benzyloxy-5-bromo-phenylacetic acid

Lösungsmittel

dimethylformamide

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONpoured onto ice water
2. 2
   Extraktionextracted with ethyl acetate
3. 3
   SonstigeThe combined organic extracts are dried
4. 4
   Sonstigeevaporated down
5. 5
   workup.DISSOLUTIONThe residue is dissolved in 100 ml of ethanol
6. 6
   workup.ADDITIONafter the addition of 50 ml of 2N sodium hydroxide solution
7. 7
   workup.STIRRINGstirred for 3 hours at ambient temperature
8. 8
   workup.DISTILLATIONThe solvent is distilled off
9. 9
   ExtraktionAfter extraction with ethyl acetate the organic phases
10. 10
    Sonstigeare dried
11. 11
    Sonstigeevaporated down
12. 12
    SonstigeThe residue is chromatographed on silica gel
13. 13
    Wascheneluted with petroleum ether/ethyl acetate (8:2)

Vorschrift

A solution of 12.4 g (0.053 mol) of 2-hydroxy-5-bromo-phenylacetic acid in 125 ml of dimethylformamide is combined with 14 g (0.125 mol) of potassium tert.butoxide. After 15 minutes at ambient temperature 18.5 g (0.108 mol) of benzylbromide are added. The reaction solution is stirred for 3 hours at ambient temperature, poured onto ice water and extracted with ethyl acetate. The combined organic extracts are dried and evaporated down. The residue is dissolved in 100 ml of ethanol and after the addition of 50 ml of 2N sodium hydroxide solution stirred for 3 hours at ambient temperature. The solvent is distilled off, the residue is adjusted to pH 4 with 2N hydrochloric acid. After extraction with ethyl acetate the organic phases are dried and evaporated down. The residue is chromatographed on silica gel and eluted with petroleum ether/ethyl acetate (8:2).

Quelle