Acetic Acid → 3,4-Dibromobenzoic acid

HRID 987169Notes

Reaction equation

HRID 987169 reaction equation
[Mn]([O-])(=O)(=O)=O.[K+].[Br:7][C:8]1[CH:9]=C(C)[CH:11]=[CH:12][C:13]=1[Br:14].[C:16]([OH:19])(=[O:18])[CH3:17]>>[Br:7][C:8]1[CH:9]=[C:17]([CH:11]=[CH:12][C:13]=1[Br:14])[C:16]([OH:19])=[O:18]

Participants

4

Reactant 3

HCID 176Acetic AcidHCID 346791,2-Dibromo-4-methylbenzeneHCID 516875Potassium Permanganate

Product 1

HCID 6243973,4-Dibromobenzoic acidYield 37%

Conditions

Temperature
80 °C

Procedure

A saturated aqueous solution of potassium permanganate (61.3 g, 388 mmol) was added in portions to a well stirred solution of 3,4-dibromotoluene (40.4 g, 162 mmol) in acetic acid (700 mL) while maintaining the temperature between 70 and 80° C. After addition, the suspension was stirred for an additional 4 hours at 80° C. The solution was concentrated on a rotary evaporator, the residue treated with 5 N NaOH (700 mL) and heated under reflux for 2 hours. The MnO2 cake was filtered from solution and washed thoroughly with hot water. The filtrate was extracted with hexane (2×100 mL) and acidified with concentrated HCl pH 2. Collected white precipitate by filtration. Washed precipitate with water and dried under high vacuum. Obtained 16.59 gram (37% yield) of 3,4-dibromobenzoic acid. 1H NMR (300 MHz, DMSO-d6): δ13.47 (singlet, 1H), 8.14 (singlet, 1H), 7.88 (doublet, J=8.1 Hz, 1H), 7.99 (doublet, J=8.1 Hz, 1H). 13C NMR (300 MHz, DMSO-d6): δ165.72, 134.42, 134.18, 132.07, 129.96, 129.32, 124.40.

Workup

  1. temperaturewhile maintaining the temperature between 70 and 80° C
  2. additionAfter addition
  3. concentrationThe solution was concentrated on a rotary evaporator
  4. additionthe residue treated with 5 N NaOH (700 mL)
  5. temperatureheated
  6. temperatureunder reflux for 2 hours
  7. filtrationThe MnO2 cake was filtered from solution
  8. washwashed thoroughly with hot water
  9. extractionThe filtrate was extracted with hexane (2×100 mL)
  10. customCollected white precipitate
  11. filtrationby filtration
  12. washWashed precipitate with water
  13. customdried under high vacuum

Sources & evidence

ORD record
ord-dcdaee27e62b4d1a918f43bbcf80a4c4
Source dataset
uspto-grants-2003_10
Patent number
US06630577B2

Reaction notes

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