Sulfuric Acid → 3,5-Dichloro-4-fluorobenzoic acid
Reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]([CH:8]=[C:9]([Cl:12])[C:10]=1[F:11])[C:5](Cl)=[O:6].ClC1C=C(C(F)(F)F)C=C(Cl)C=1F.S(=O)(=O)(O)[OH:27].ClS(O)(=O)=O>>[Cl:1][C:2]1[CH:3]=[C:4]([CH:8]=[C:9]([Cl:12])[C:10]=1[F:11])[C:5]([OH:27])=[O:6]Participants
Conditions
- Temperature
- 50 °C
Procedure
3,5-dichloro-4-fluorobenzoyl chloride can be prepared as follows: To a round bottom flask with nitrogen purge through a 10% aqueous NaOH trap, was added 3,5-dichloro-4-flurobenzotriflouride (5.00 g, 21.46 mmol, Aldrich), concentrated sulfuric acid (4.30 g, 42.92 mmol), and finally chlorosulfonic acid (5.15 g, 43.78 mmol). The reaction began to bubble immediately. After the bubbling subsided, the mixture was heated to 50° C. for 1 hr, cooled to room temperature, and added cautiously to stirred ice water. This was extracted twice with methylene chloride. The combined extracts were washed with water and brine, dried over magnesium sulfate, filtered, and evaporated to give a white solid (2.19 g) of 3,5-dichloro-4-fluorobenzoic acid in 49% yield. 1H NMR (CD3COCD3, 300 MHz) δ (ppm): 7.95 (d, 2H).
Workup
- customTo a round bottom flask with nitrogen purge through a 10% aqueous NaOH trap
- customto bubble immediately
- temperaturecooled to room temperature
- additionadded cautiously
- extractionThis was extracted twice with methylene chloride
- washThe combined extracts were washed with water and brine
- dry with materialdried over magnesium sulfate
- filtrationfiltered
- customevaporated
Sources & evidence
- ORD record
- ord-9061eebd0f80444dac4f4f84f7ad823c
- Source dataset
- uspto-grants-2016_02
- Patent number
- US09255273B2
Reaction notes
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