Sulfuric Acid → 5-Fluoro-3-nitrobenzene-1,2-diol

Temperature

28 °C

H2SO4 (50 mL) was added to a solution of H3BO3 (89.3 g, 1.4 mol) in 1,4-Dioxane (300 mL) at 0° C. and stirred at 28° C. for 1 h. 1-(5-fluoro-2-hydroxy-3-nitrophenyl)ethanone (50 g, 289 mmol) was added portion wise to the above solution over 1 h, maintaining the temperature at 0° C., after addition was complete, the reaction mixture was warmed to 25° C. and stirred for 16 h. Reaction mixture was quenched with cold water, solid separated was collected by filtration. The solid was suspended in diethyl ether (500 mL) and filtered to remove insoluble inorganic mass, ether layer was washed with cold water (2 to 3 times) followed by brine, dried over anhydrous sodium sulphate and concentrated under reduced pressure to afford the crude sticky solid. The crude solid was triturated over n-Hexane and filtered to afford 5-fluoro-3-nitrobenzene-1,2-diol (Int-50) as pale yellow solid. MS (ESI): m/z 171.9 (M−1).

1. temperaturemaintaining the temperature at 0° C.
2. additionafter addition
3. temperaturethe reaction mixture was warmed to 25° C.
4. stirringstirred for 16 h
5. customReaction mixture
6. customwas quenched with cold water, solid
7. customseparated
8. filtrationwas collected by filtration
9. filtrationfiltered
10. customto remove insoluble inorganic mass, ether layer
11. washwas washed with cold water (2 to 3 times)
12. dry with materialdried over anhydrous sodium sulphate
13. concentrationconcentrated under reduced pressure
14. customto afford the crude sticky solid
15. customThe crude solid was triturated over n-Hexane
16. filtrationfiltered

ORD record

ord-4c68f5f294304c4abed1adc91e524bd8

Source dataset

uspto-grants-2015_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09045478B2