Reaktion #353927

Reaktionsgleichung

benzyl bromide

Sodium hydride

hexane

4-hydroxyphenylacetic acid

→

benzyl 4-hydroxyphenylacetate

Lösungsmittel

DMF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITwas continued overnight at ambient temperature
2. 2
   SonstigeThe solvent was evaporated in vacuo
3. 3
   Sonstigethe residue partitioned between ethyl acetate and water
4. 4
   ExtraktionThe aqueous phase was re-extracted with further ethyl acetate
5. 5
   Waschenthe combined organic extracts washed with water and brine
6. 6
   Trocknendried (MgSO4)
7. 7
   Sonstigeevaporated

Vorschrift

Sodium hydride (50% w/w dispersion in mineral oil, 3.7 g) was treated under argon with repeated washes of hexane. The oil-free residue was suspended in dry DMF (100 ml) and 4-hydroxyphenylacetic acid (13.0 g) was added portionwise to the stirred cooled (4° C.) mixture. After 30 minutes, benzyl bromide (9.2 ml) was added dropwise and, after a further 1 hour at 4° C., stirring was continued overnight at ambient temperature. The solvent was evaporated in vacuo and the residue partitioned between ethyl acetate and water. The aqueous phase was re-extracted with further ethyl acetate and the combined organic extracts washed with water and brine, then dried (MgSO4) and evaporated. The crystalline residue gave benzyl 4-hydroxyphenylacetate, 17.8g, as off-white crystals: m.p. 70°-72° C.; NMR (CDCl3) δ 7.32(5H, m), 7.14(2H, d), 6.76(2H, d), 5.12(2H, s), 3.59(2H, s); m/e 242 (M*)+.

Quelle