反应详情

温度

50 °C

To a solution of 540 mg(1.1 mmol) of the ester from Step 4 in THF (11 mL) and MeOH (5.5 mL) was added aqueous LiOH 1.0N (3 mL, 3 mmol). The resulting solution was heated at 50° C. for 5 hours. The reaction was diluted with aqueous NH4OAc 25% w/v (50 mL) and the mixture was extracted with EtOAc. The organic layer was dried over MgSO4 and concentrated. The resulting residue was purified by crystallization in EtOAc/hexane (1:4, 30 mL) to give the title compound as a white solid; m.p. 157° C. The sodium salt was prepared by dissolving the acid in ethanol, adding one equivalent of aqueous NaOH, and freeze drying the resulting solution. The sodium salts of the remaining examples were prepared in the same way.

1. extractionthe mixture was extracted with EtOAc
2. dry with materialThe organic layer was dried over MgSO4
3. concentrationconcentrated
4. customThe resulting residue was purified by crystallization in EtOAc/hexane (1:4, 30 mL)