Pyridine → 3,5-Difluoro-4-formylphenyl octan-2-yl carbonate

Beteiligte Stoffe

Reaktionsschritte

To a 250 mL dry round bottom flask were added 2-octanol (4.51 g, 34.6 mmol), triphosgene (3.44 g, 11.6 mmol) and anhydrous THF (100 mL). The mixture was stirred in an ice-water bath, then pyridine (5.6 mL, 69.2 mmol) was injected slowly. After stirring at room temperature for 30 minutes, the mixture was filtered, and the filtrate was concentrated. The residue was dissolved in 15 mL of CH2Cl2 and cooled in an ice-water bath. To this stirring solution, a solution of 2,6-difluoro-4-hydroxybenzaldehyde (4.2 g, 26.6 mmol) and pyridine (2.80 mL, 34.6 mmol) in 20 mL of anhydrous CH2Cl2 was added slowly. After stirring at room temperature for 2 hours, water (80 mL) was added to the reaction mixture. The CH2Cl2 layer was separated, and the aqueous layer was extracted continually with CH2Cl2 (100 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 octan-2-yl carbonate (5.0 g) as a colorless oil. Yield: 46%. 13C NMR (CDCl3, 75.5 MHz): δ=183.2, 163.4 (dd, J=263.0, 8.53 Hz), 156.3 (t, J=15.2 Hz), 151.2, 111.8 (t, J=11.0 Hz), 105.9 (dd, J=25.7, 3.62 Hz), 78.0, 35.6, 31.6, 28.9, 25.1, 22.4, 19.6, 13.9.

Herkunft & Nachweise