Sulfuric Acid → 4-Bromo-2-nitrobenzoic acid

Temperature

-20 °C

A solution (250 mL) of 2,5-dibromo-1-nitrobenzene (4.32 g, 15.4 mmol) in THF was cooled to −105° C. and 0.88 M phenyllithium/THF solution (19.8 mL, 17.4 mmol) was slowly added dropwise. After 30 min, DMF (5.4 mL, 69.6 mmol) was slowly added dropwise and the temperature was slowly raised to −20° C. Dilute aqueous sulfuric acid solution (100 mL) was added to the reaction mixture and the mixture was concentrated. The product was extracted with ethyl acetate (80 mL×2). The organic layer was dried, concentrated and the resulting brown solid (5.66 g) was dissolved in acetone (50 mL). Jone's reagent (20 mL) was slowly added to this solution under ice-cooling, and the temperature was slowly raised to room temperature. Isopropanol was added to the reaction mixture and the mixture was concentrated. 2 mol/L Aqueous sodium hydroxide solution (100 mL) was added and the mixture was filtered. Concentrated hydrochloric acid was added to acidify the filtrate. The precipitate was collected by filtration and the residue was washed with water and dried to give 4-bromo-2-nitrobenzoic acid (1.95 g, 52%).

1. concentrationthe mixture was concentrated
2. extractionThe product was extracted with ethyl acetate (80 mL×2)
3. customThe organic layer was dried
4. concentrationconcentrated
5. dissolutionthe resulting brown solid (5.66 g) was dissolved in acetone (50 mL)
6. additionJone's reagent (20 mL) was slowly added to this solution under ice-
7. temperaturecooling
8. temperaturethe temperature was slowly raised to room temperature
9. additionIsopropanol was added to the reaction mixture
10. concentrationthe mixture was concentrated
11. addition2 mol/L Aqueous sodium hydroxide solution (100 mL) was added
12. filtrationthe mixture was filtered
13. additionConcentrated hydrochloric acid was added
14. filtrationThe precipitate was collected by filtration
15. washthe residue was washed with water
16. customdried

ORD record

ord-e83700d0b64041868f46050c9e905b4d

Source dataset

uspto-grants-2007_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07294629B2