Triethylamine → 3-Fluoro-4-formylphenyl 2-oxooxazolidine-3-carboxylate

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Reaction Steps

To a 250 mL dry round bottom flask were added 2-oxazolidinone (4.35 g, 50.0 mmol), triphosgene (5.49 g, 18.5 mmol) and anhydrous THF (100 mL). The mixture was stirred in an ice-water bath, then triethylamine (9.8 mL, 70.0 mmol) was added slowly. After stirring at 0° C. for 1 hour, the mixture was stirred continually at room temperature overnight. The reaction mixture was filtered and the filtrate was concentrated. The residue was dissolved in 10 mL of CH2Cl2, and this solution was added slowly to a stirring mixture of 2-fluoro-4-hydroxybenzaldehyde (3.78 g, 27.0 mmol) and triethylamine (5.63 mL, 40.4 mmol) in 20 mL of anhydrous CH2Cl2 at 0° C. After stirring at room temperature for 2 days, water (80 mL) and MTBE (100 mL) were added to the reaction mixture. The mixture was filtered and the solid was washed with cold water (50 mL×2), followed by extraction using MTBE (50 mL×4). After drying, 3-fluoro-4-formylphenyl 2-oxooxazolidine-3-carboxylate (5.90 g) was obtained as a white solid. Yield: 86%. 1H NMR (CDCl3, 300 MHz): δ=10.42 (s, 1H), 8.03 (t, J=8.1 Hz, 1H), 7.27-7.23 (m, 2H), 4.61 (t, J=7.8 Hz, 2H), 4.29 (t, J=7.5 Hz, 2H). 13C NMR (CDCl3, 75.5 MHz): δ=186.3 (d, J=6.0 Hz), 166.9, 155.0 (d, J=260 Hz), 130.2, 122.6, 118.3, 110.7 (d, J=24.4 Hz), 62.2, 43.9. 19F NMR (CDCl3, 282.3 MHz): δ=−118.6.

Provenance & Evidence