Reaktion #630390

Reaktionsgleichung

6-Hydroxy-2(S)-phthalimidohexanoic acid

cesium carbonate

→

benzyl 6-hydroxy-2(S)-phthalimidohexanoate

Ausbeute 198.6%

Lösungsmittel

methanol

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeMost of the methanol was removed in vacuo
2. 2
   Sonstigethe resulting aqueous residue was freeze-dried
3. 3
   workup.DISSOLUTIONThe lyophilized material was dissolved in DMF (70 ml)
4. 4
   workup.ADDITIONtreated with 3.08 g of benzyl bromide
5. 5
   workup.STIRRINGAfter stirring under nitrogen for 6 hours
6. 6
   workup.ADDITIONthe reaction mixture was diluted with 450 ml of water
7. 7
   Extraktionrepeatedly extracted with ethyl acetate
8. 8
   WaschenOrganic layers were then back-washed with water
9. 9
   Trocknendried (Na2SO4)
10. 10
    Einengenconcentrated

Vorschrift

6-Hydroxy-2(S)-phthalimidohexanoic acid (5.0 g) was dissolved in a mixture of 90 ml of methanol and 9 ml of water. To this solution, an aqueous 0.5M cesium carbonate solution (18 ml) was added and the mixture stirred for a few minutes. Most of the methanol was removed in vacuo and the resulting aqueous residue was freeze-dried. The lyophilized material was dissolved in DMF (70 ml) and treated with 3.08 g of benzyl bromide. After stirring under nitrogen for 6 hours, the reaction mixture was diluted with 450 ml of water and repeatedly extracted with ethyl acetate. Organic layers were then back-washed with water, dried (Na2SO4), and concentrated to give 6.58 g of benzyl 6-hydroxy-2(S)-phthalimidohexanoate. Recrystallization from ether gave a white solid, m.p. 106.5°-108°; [α]D25° =-27.6° (MeOH, c=1.77).

Quelle