反应详情

To a stirred solution of 2-(4-fluoro-benzylidene)-succinic acid 1-methyl ester (2 g, 8.4 mmol) in acetic anhydride (10 mL) was added sodium acetate (0.83 g, 10.1 mmol). After being heated at reflux for 6 hours, the mixture was concentrated in vacuo. The residue was dissolved in 1 N hydrochloric acid (20 mL). The aqueous solution was extracted with ethyl acetate (15 mL×3). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified by column chromatography (gradient elution with 10-20% ethyl acetate in petroleum ether) to afford 4-acetoxy-6-fluoro-naphthalene-2-carboxylic acid methyl ester (1.1 g, 50%) as a white solid. 1H NMR (400 MHz, CDCl3) δ ppm 8.52 (s, 1H), 8.00 (dd, J=9.09, 5.56 Hz, 1H), 7.89 (s, 1H), 7.50 (dd, J=9.85, 2.53 Hz, 1H), 7.37 (td, J=8.59, 2.53 Hz, 1H), 3.99 (s, 3H), 2.49 (s, 3H).

1. temperatureAfter being heated
2. temperatureat reflux for 6 hours
3. concentrationthe mixture was concentrated in vacuo
4. dissolutionThe residue was dissolved in 1 N hydrochloric acid (20 mL)
5. extractionThe aqueous solution was extracted with ethyl acetate (15 mL×3)
6. dry with materialThe combined organic layers were dried over sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated in vacuo
9. customThe residue was purified by column chromatography (gradient elution with 10-20% ethyl acetate in petroleum ether)