反应详情

The intermediate prepared in Example 8 (280 g, 1.06 mol) was dissolved in acetic anhydride (650 mL) followed by slow addition of conc. H2SO4 (60 mL). The pot temperature reached 80° C. The reaction was then held at 85° C. for 1 hour, cooled, and the acetic anhydride removed in vacuo. The residue was poured into ice water (2 L) and extracted with EtOAc (4 L total). The organic layer was then stirred with 1N NaOH (500 mL) for 1 hour, separated, then dried with MgSO4 and concentrated to afford the title ester as a clear oil (223 g, 87%), which slowly solidified to a white solid.

1. customreached 80° C
2. temperaturecooled
3. customthe acetic anhydride removed in vacuo
4. additionThe residue was poured into ice water (2 L)
5. extractionextracted with EtOAc (4 L total)
6. customseparated
7. dry with materialdried with MgSO4
8. concentrationconcentrated