Water → 4-Bromobenzoic acid

HRID 928908Notes

Reaction equation

HRID 928908 reaction equation
[O-:1][Mn](=O)(=O)=O.[K+].[Br:7][C:8]1[CH:13]=[CH:12][C:11]([CH3:14])=[CH:10][CH:9]=1.[OH2:15]>>[Br:7][C:8]1[CH:13]=[CH:12][C:11]([C:14]([OH:1])=[O:15])=[CH:10][CH:9]=1

Participants

4

Reactant 3

HCID 962WaterHCID 78054-BromotolueneHCID 516875Potassium Permanganate4×

Product 1

HCID 114644-Bromobenzoic acidYield 41%

Conditions

Temperature
60 °C

Procedure

KMnO4 was added in three portions according to the following procedure: KMnO4 (1.515 g, 9.59 mmol) was suspended in water (20 mL). 4-bromotoluene was added dropwise while the reaction stirred vigorously at 60° C. The mixture was allowed to reflux overnight with a loosely placed septum. A second portion of KMnO4 (0.773 g, 4.795 mmol) was added and reaction allowed to continue reflux for 8.5 hr. A final portion of KMnO4 was added and the reaction allowed to reflux for an additional 48 hr, until deemed complete by the consumption of KMnO4 and the formation MnO2. The reaction was filtered under vacuum and precipitate was rinsed with hot water. The aqueous solution was extracted with EtOAc and then acidified to pH 2-3 (as indicated by pH paper). The aqueous layer extracted again with 2× equal volume EtOAc. Pooled organic layers from the second extraction were dried over anhydrous Na2SO4 and evaporated to dryness to afford 4-bromobenzoic acid (0.673 g, 3.3 mmol, 41%). 1H-NMR (CD2Cl2, 500 MHz) δ (ppm): 7.63 (d, J=14.1 Hz, 2H); 7.94 (d, J=17.2 Hz, 2H).

Workup

  1. temperatureto reflux overnight with a loosely placed septum
  2. customreaction
  3. temperatureto continue reflux for 8.5 hr
  4. temperatureto reflux for an additional 48 hr
  5. customuntil deemed complete by the consumption of KMnO4
  6. filtrationThe reaction was filtered under vacuum and precipitate
  7. washwas rinsed with hot water
  8. extractionThe aqueous solution was extracted with EtOAc
  9. extractionThe aqueous layer extracted again with 2× equal volume EtOAc
  10. extractionPooled organic layers from the second extraction
  11. dry with materialwere dried over anhydrous Na2SO4
  12. customevaporated to dryness

Sources & evidence

ORD record
ord-d3cd5bdaa961414aa61cbf2fc66517af
Source dataset
uspto-grants-2016_03
Patent number
US09290791B2

Reaction notes

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