Реакция #155419

Уравнение реакции

2,6-difluoro-4-hydroxybenzaldehyde

pyridine

2-oxazolidinone

triphosgene

triethylamine

→

3,5-difluoro-4-formylphenyl 2-oxooxazolidine-3-carboxylate

Выход 98.1%

Растворители

CH2Cl2

water

THF

Условия реакции

Обработка

1. 1
   ДругоеTo a 250 mL dry round bottom flask
2. 2
   workup.STIRRINGAfter stirring at 0° C. for 1 hour
3. 3
   workup.STIRRINGthe mixture was stirred continually at room temperature overnight
4. 4
   ФильтрацияThe reaction mixture was filtered
5. 5
   Концентрированиеthe filtrate was concentrated
6. 6
   workup.DISSOLUTIONThe residue was dissolved in 20 mL of CH2Cl2
7. 7
   workup.STIRRINGAfter stirring at room temperature for 10 hours
8. 8
   ДругоеThe CH2Cl2 layer was separated
9. 9
   Экстракцияthe aqueous layer was extracted continually with CH2Cl2 (50 mL×4)
10. 10
    СушкаThe combined CH2Cl2 solution was dried over Na2SO4
11. 11
    ДругоеAfter removal of the solvent
12. 12
    Другоеthe residue was purified with a silica gel chromatography (heptane/ethyl acetate, gradient eluting)

Методика

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 (80 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 20 mL of CH2Cl2, and this solution was added slowly to a stirring mixture of 2,6-difluoro-4-hydroxybenzaldehyde (5.93 g, 27.5 mmol) and pyridine (4.44 mL, 55.0 mmol) in 30 mL of anhydrous CH2Cl2 at 0° C. After stirring at room temperature for 10 hours, water (100 mL) was added to the reaction mixture. The CH2Cl2 layer was separated, and the aqueous layer was extracted continually with CH2Cl2 (50 mL×4). The combined CH2Cl2 solution was dried over Na2SO4. After removal of the solvent, the residue was purified with a silica gel chromatography (heptane/ethyl acetate, gradient eluting) to give 3,5-difluoro-4-formylphenyl 2-oxooxazolidine-3-carboxylate (4.92 g) as a white solid. Yield: 33%. 1H NMR (CDCl3, 300 MHz): δ=10.29 (s, 1H), 6.98 (dd, J=10.8, 2.1 Hz, 2H), 4.51 (t, J=7.8 Hz, 2H), 4.18 (t, J=7.6 Hz, 2H). 13C NMR (CDCl3, 75.5 MHz): δ=183.5, 163.7 (dd, J=263.6, 8.00 Hz), 151.2, 148.0, 112.6, 106.8 (dd, J=25.7, 3.70 Hz), 62.1, 43.7.

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