反应详情

A solution of the ester of Step A, above (2.0 g, 4.2 mmol) in tetrahydrofuran (100 mL) and 1N LiOH (12.7 mL) is stirred under nitrogen overnight. The solvent is removed and the residue slurried in water. The mixture is acidified using dilute HCl and extracted with ethyl acetate (2×500 mL). The combined organic phases are washed with brine and dried (MgSO4). Removal of the solvent affords a brown oil which crystallizes from acetonitrile (white solid, 0.620 g, approximately 90% pure by HPLC). This material is further purified by HPLC (Dynamax C18, 2"-column, acetonitrileammonium acetate buffer 3:2) to provide pure title compound (0.250 g, white solid, m.p. 128°-131° C., dec.).

1. customThe solvent is removed
2. extractionextracted with ethyl acetate (2×500 mL)
3. washThe combined organic phases are washed with brine
4. dry with materialdried (MgSO4)
5. customRemoval of the solvent
6. customaffords a brown oil which
7. customcrystallizes from acetonitrile (white solid, 0.620 g, approximately 90% pure by HPLC)
8. customThis material is further purified by HPLC (Dynamax C18, 2"-column, acetonitrileammonium acetate buffer 3:2)