Boron tribromide → 2,4-Difluoro-6-hydroxybenzaldehyde

To a solution of 2,4-difluoro-6-methoxybenzaldehyde (Description 69, 11.2 g; 77.8 mmol) in anhydrous dichloromethane (500 ml) cooled at −78° C. was added boron tribromide (9.47 ml; 85.58 mmol) dropwise over 10 minutes. After complete addition the mixture was allowed to warm to room temperature and stirred overnight. The mixture was poured onto ice/water (1 litre) and extracted with DCM (3×400 ml). The combined organic layers were washed with water (1 litre), saturated NaCl (500 ml), dried over Na2SO4, filtered and evaporated. The residue was purified by column chromatography on silica elution with 10% diethyl ether/isohexanes to give the title compound (9.2 g, 75%) as an orange oil.

1. additionAfter complete addition the mixture
2. additionThe mixture was poured onto ice/water (1 litre)
3. extractionextracted with DCM (3×400 ml)
4. washThe combined organic layers were washed with water (1 litre), saturated NaCl (500 ml)
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. customevaporated
8. customThe residue was purified by column chromatography on silica elution with 10% diethyl ether/isohexanes

ORD-Eintrag

ord-0ddcb55e59fd43719d4b45e35f282210

Quelldatensatz

uspto-grants-2007_10

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07285563B2