Dimethyl Sulfoxide → 4,5-Difluorophthalaldehyde

Temperatur

-78 °C

To a solution of oxalyl chloride 2M in dichloromethane (DCM) (4.5 ml, 8.8 mmol, 2.2 molar equivalents) cooled to −78° C. was added dropwise a solution of dimethylsulfoxyde (DMSO) (1.25 ml, 17.7 mmol, 4.4 molar equivalents) in DCM (5 ml). The solution was stirred at −78° C. for 5 minutes and 4,5-difluorobenzene-1,2-dimethanol (compound 21) (0.70 g, 4.0 mmol, 1.0 molar equivalent) dissolved in a mixture of DCM/DMSO (1-2 ml) was added dropwise. The solution was stirred for 1 hour at −78° C. and triethylamine (15 ml) was slowly added at −78° C. The reaction mixture was stirred for 10 minutes at −78° C. and slowly warmed up to room temperature. Ice-cold water (25 ml) was added to the reaction mixture and the aqueous layer extracted with DCM (3 times 30 ml). The organic fractions were combined, dried over magnesium sulfate, filtered and concentrated in vacuum to give a yellow oil. Purification by column chromatography on silica gel (eluent, hexane:DCM 2:8) gave the title compound as a light yellow solid (0.58 g, 85%). 1H NMR (300.13 MHz, CDCl3) δ(ppm) 7.83 (t, J=9.00 Hz, 2H) 10.49 (s, 2H). 19F NMR (282.38 MHz, CDCl3) δ(ppm) −127.10 (s).

1. additionwas added dropwise
2. stirringThe solution was stirred for 1 hour at −78° C.
3. stirringThe reaction mixture was stirred for 10 minutes at −78° C.
4. temperatureslowly warmed up to room temperature
5. extractionthe aqueous layer extracted with DCM (3 times 30 ml)
6. dry with materialdried over magnesium sulfate
7. filtrationfiltered
8. concentrationconcentrated in vacuum
9. customto give a yellow oil
10. customPurification by column chromatography on silica gel (eluent, hexane:DCM 2:8)

ORD-Eintrag

ord-e03cf5886ca14e67b1b04450d8ddd9ab

Quelldatensatz

uspto-grants-2012_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08119804B2