反应详情

A solution of the ester (115) (1.48 g, 3.39 mmol) in 1:1:1 THF-methanol-aq. 1M LiOH (102 ml) was stirred at 60° C., then at room temperature overnight. The reaction mixture was then concentrated into approximately ⅓ of the volume, diluted with water (30 ml) and acidified to approx. pH 4 using aq. 10% citric acid (60 ml), then washed with ethyl acetate (3×50 ml). The combined organic layers were washed with brine (1×100 ml), then dried (Na2SO4), filtered and concentrated. Column chromatography of the residue using 9:1 ethyl acetate-methanol as eluent gave the title compound as a slight yellow (The coloring from the previous step was removed during work up and chromatography). Yield: 1.35 g, 97%. LR-MS: Calcd for C21H31N2O6: 407. Found: 407 [M−H].

1. customat room temperature
2. customovernight
3. concentrationThe reaction mixture was then concentrated into approximately ⅓ of the volume
4. additiondiluted with water (30 ml)
5. washwashed with ethyl acetate (3×50 ml)
6. washThe combined organic layers were washed with brine (1×100 ml)
7. dry with materialdried (Na2SO4)
8. filtrationfiltered
9. concentrationconcentrated