Reaction equation
[CH3:1][O:2][C:3](=[O:17])[C:4](=[CH:9][C:10]1[CH:15]=[CH:14][C:13]([F:16])=[CH:12][CH:11]=1)[CH2:5][C:6]([OH:8])=O.[C:18]([O-])(=[O:20])[CH3:19].[Na+]>C(OC(=O)C)(=O)C>[CH3:1][O:2][C:3]([C:4]1[CH:5]=[C:6]([O:8][C:18](=[O:20])[CH3:19])[C:15]2[C:10](=[CH:11][CH:12]=[C:13]([F:16])[CH:14]=2)[CH:9]=1)=[O:17]Participants
Procedure
To a 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, and concentrated in vacuo. The residue was purified by column chromatography (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).
Workup
- temperatureAfter being heated
- temperatureat reflux for 6 hours
- concentrationthe mixture was concentrated in vacuo
- dissolutionThe residue was dissolved in 1 N hydrochloric acid (20 mL)
- extractionThe aqueous solution was extracted with ethyl acetate (15 mL×3)
- dry with materialThe combined organic layers were dried over sodium sulfate
- concentrationconcentrated in vacuo
- customThe residue was purified by column chromatography (10-20% ethyl acetate in petroleum ether)
Sources & evidence
- ORD record
- ord-bbd9a9ded1fa4e4e8ab3fb25af3617bd
- Source dataset
- uspto-grants-2014_02
- Patent number
- US08642629B2
Linked notes
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