Boron tribromide → 4-Bromo-5-fluorobenzene-1,2-diol

Temperature

20 °C

To a cooled (−78° C.) solution of 4-fluoroveratrole (5.0 g, 32 mmol) in dichloromethane (106 mL) was slowly added a solution of tribromoborane in dichloromethane (1M, 96 mL, 96 mmol, 3.0 eq.). The reaction mixture was warmed to 20° C. and stirred overnight. The reaction mixture was poured into ice water, extracted with ethyl acetate (3 times). The combined organic layer was washed with an aqueous solution of sodium bicarbonate, dried over sodium sulfate and filtered. The volatiles were removed in vacuo. The brown solid was diluted with chloroform (50 mL) and dichloromethane (10 mL). A solution of bromine in carbon tetrachloride (5 ml) was slowly added. After 3 hours, the volatiles were removed in vacuo. Purification by flash chromatography afforded the title compound (6.51 g, 98%) as a brown solid

1. extractionextracted with ethyl acetate (3 times)
2. washThe combined organic layer was washed with an aqueous solution of sodium bicarbonate
3. dry with materialdried over sodium sulfate
4. filtrationfiltered
5. customThe volatiles were removed in vacuo
6. additionThe brown solid was diluted with chloroform (50 mL) and dichloromethane (10 mL)
7. additionA solution of bromine in carbon tetrachloride (5 ml) was slowly added
8. waitAfter 3 hours
9. customthe volatiles were removed in vacuo
10. customPurification by flash chromatography

ORD record

ord-c7f065407b7b4abe9f1ecd713385c201

Source dataset

uspto-grants-2005_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06900227B2