反应详情

The ester of step 1 (26.45 g, 86.62 mmol) was dissolved in 250 mL of tetrahydrofuran and treated with a solution of lithium hydroxide monohydrate (10.65 g, 256 mmol) in 250 mL of water and stirred at ambient temperature for 24 h. The reaction mixture was cooled to 0° C. and neutralized with 300 mL of a 1N HCl solution. Ethyl acetate (400 mL) was added and the organic layer was separated, dried over sodium sulfate, filtered and concentrated to give a crude solid. The product was purified by recrystallizing from ethyl acetate/hexanes to give 19.60 g of a white solid. Yield: 82%, MS: 278 (M+H+), mp=120.1-123.1° C.

1. customthe organic layer was separated
2. dry with materialdried over sodium sulfate
3. filtrationfiltered
4. concentrationconcentrated
5. customto give a crude solid
6. customThe product was purified
7. customby recrystallizing from ethyl acetate/hexanes