反应详情

Methyl 8-fluoro-2H-1-benzopyran-5-carboxylate (7.36 g, 35.4 mmol) was dissolved in absolute ethanol (220 mL), NaOH (2.0 g, 49.6 mmol) in H2O (25 mL), was added thereto, and the reaction mixture was refluxed for 1.5 hour. The reaction mixture was cooled and the solvent was removed in vacuo. The yellow solid was dissolved in H2O (150 mL), active charcoal was added and then filtered off. The resulting light-coloured liquid was washed with diethyl ether, the aqueous solution was made acidic with 2 M HCl and the product was extracted twice with ethyl acetate. The combined organic portions were treated with brine, dried with MgSO4, filtered, and the solvent was removed in vacuo to give 6.64 g (97% yield) of a yellowish solid (dried in a desiccator over P2O5) as the title compound (mp 224-226° C.). EIMS (70 eV) m/z (relative intensity) 194 (93, M+), 193 (100), 149 (56), 148 (68), 120 (13), 88 (25), 75 (28), 74 (21), 60 (12).

1. temperaturethe reaction mixture was refluxed for 1.5 hour
2. temperatureThe reaction mixture was cooled
3. customthe solvent was removed in vacuo
4. dissolutionThe yellow solid was dissolved in H2O (150 mL)
5. additionactive charcoal was added
6. filtrationfiltered off
7. washThe resulting light-coloured liquid was washed with diethyl ether
8. extractionthe product was extracted twice with ethyl acetate
9. additionThe combined organic portions were treated with brine
10. dry with materialdried with MgSO4
11. filtrationfiltered
12. customthe solvent was removed in vacuo