反应详情

The ester from Step 1 (0.300 g, 0.727 mmol) was dissolved in THF-ethanol-water (7:2:1, 10 mL). It was treated with sodium hydroxide (0.29 mL of a 2.5 N solution, 0.727 mmol), and stirred at room temperature for 18 hours. The solvent was evaporated and the residue was dissolved in water (10 mL). Ether (10 mL) was added, followed by a few drops of concentrated HCl. The ether layer was separated, and the aqueous phase was extracted with ether (2×10 mL). The ether extracts were combined, dried over MgSO4, filtered, and concentrated in vacuo to yield a white solid, which was recrystallized in diethyl ether-hexane to afford the title compound as a white solid (0.23 g, 81%): mp 173.1–177.4° C. 1H NMR (CDCl3/300 MHz) 7.81 (s, 1H), 7.39–7.37 (m, 2H ), 7.05–7.04 (m, 2H), 6.97–6.94 (m, 1H), 5.71 (q, 1H, J=6.7 Hz), 3.85 (s, 3H). ESHRMS m/z 383.0278 (M−H, Calc'd. 383.029796). Anal. Calc'd. for C18H12ClF3O4: C, 56.20; H, 3.14; Cl, 9.21. Found: C, 55.90; H, 3.11; Cl, 9.48.

1. customThe solvent was evaporated
2. dissolutionthe residue was dissolved in water (10 mL)
3. additionEther (10 mL) was added
4. customThe ether layer was separated
5. extractionthe aqueous phase was extracted with ether (2×10 mL)
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated in vacuo
9. customto yield a white solid, which
10. customwas recrystallized in diethyl ether-hexane