Réaction #155428

Équation de réaction

2,6-difluoro-4-hydroxybenzaldehyde

CH2Cl2

pyridine

isopropyl chloroformate

→

3,5-difluoro-4-formylphenyl isopropyl carbonate

Rendement 84.0%

Solvants

Water

toluene

Conditions de réaction

Traitement

1. 1
   AutreTo a 250 mL dry round bottom flask
2. 2
   workup.STIRRINGAfter stirring at 0° C. for 2 hours
3. 3
   workup.STIRRINGthe mixture was stirred at room temperature overnight
4. 4
   AutreThe CH2Cl2 layer was separated
5. 5
   Extractionthe aqueous layer was extracted continually with CH2Cl2 (80 mL×3)
6. 6
   SéchageThe combined CH2Cl2 solution was dried over Na2SO4
7. 7
   AutreAfter removal of the solvent
8. 8
   Autrethe residue was purified with a silica gel chromatography (heptane/ethyl acetate, gradient eluting)

Mode opératoire

To a 250 mL dry round bottom flask were added 2,6-difluoro-4-hydroxybenzaldehyde (4.80 g, 30.4 mmol), anhydrous CH2Cl2 (30 mL) and pyridine (3.0 mL, 36.5 mmol). The mixture was stirred in an ice-water bath, then a solution of isopropyl chloroformate in toluene (1.0 M, 33.4 mL) was added. After stirring at 0° C. for 2 hours, the mixture was stirred at room temperature overnight. Water (80 mL) was added to the reaction mixture. The CH2Cl2 layer was separated, and the aqueous layer was extracted continually with CH2Cl2 (80 mL×3). 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 isopropyl carbonate (6.20 g) as a colorless oil. Yield: 84%. 1H NMR (CDCl3, 300 MHz): δ=10.30 (s, 1H), 7.02-6.96 (m, 2H), 5.03 (seventet, J=6.3 Hz, 1H), 1.43 (d, J=6.3 Hz, 6H). 13C NMR (CDCl3, 75.5 MHz): δ=183.3, 163.6 (dd, J=262.5, 7.92 Hz), 156.3 (t, J=15.2 Hz), 151.1, 111.9 (t, J=11.5 Hz), 106.0 (dd, J=25.1, 3.62 Hz), 74.5, 21.5. 19F NMR (CDCl3, 282.3 MHz): δ=−113.0 (d, J=9.0 Hz).

Source