反应详情

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).

1. customMost of the methanol was removed in vacuo
2. customthe resulting aqueous residue was freeze-dried
3. dissolutionThe lyophilized material was dissolved in DMF (70 ml)
4. additiontreated with 3.08 g of benzyl bromide
5. stirringAfter stirring under nitrogen for 6 hours
6. additionthe reaction mixture was diluted with 450 ml of water
7. extractionrepeatedly extracted with ethyl acetate
8. washOrganic layers were then back-washed with water
9. dry with materialdried (Na2SO4)
10. concentrationconcentrated