Potassium Permanganate → 4-Benzyloxy-3-ethyl-5-methyl-benzoic acid

HRID 1676130Notes

Reaction equation

HRID 1676130 reaction equation
[CH2:1]([O:8][C:9]1[C:16]([CH3:17])=[CH:15][C:12]([CH:13]=[O:14])=[CH:11][C:10]=1[CH2:18][CH3:19])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[O-:20][Mn](=O)(=O)=O.[K+]>CC(C)=O>[CH2:1]([O:8][C:9]1[C:16]([CH3:17])=[CH:15][C:12]([C:13]([OH:20])=[O:14])=[CH:11][C:10]=1[CH2:18][CH3:19])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

4

Reactant 2

HCID 516875Potassium PermanganateHCID 866393484-Benzyloxy-3-ethyl-5-methylbenzaldehyde

Product 1

HCID 594979194-Benzyloxy-3-ethyl-5-methyl-benzoic acidYield 69.5%

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

To a solution of 4-benzyloxy-3-ethyl-5-methyl-benzaldehyde (5.0 g, 19.7 mmol) in acetone (200 mL), KMnO4 (4.66 g, 29.5 mmol) is added. The dark violet solution becomes slightly warm and turns dark brown. The mixture is stirred at rt for 90 min before the solvent is evaporated. The residue is treated with 10% aq. citric acid soluiton (200 mL) and brine (200 mL) and extracted four times with DCM (4×200 mL). The combined organic extracts are dried over MgSO4, filtered and concentrated. The crude product is purified by CC on silica gel eluting with heptane:EA 1:1 to give 4-benzyloxy-3-ethyl-5-methyl-benzoic acid (3.70 g) as a white solid; LC-MS: tR=0.98 min, [M+1+CH3CN]+=311.97.

Workup

  1. temperatureThe dark violet solution becomes slightly warm
  2. customis evaporated
  3. additionThe residue is treated with 10% aq. citric acid soluiton (200 mL) and brine (200 mL)
  4. extractionextracted four times with DCM (4×200 mL)
  5. dry with materialThe combined organic extracts are dried over MgSO4
  6. filtrationfiltered
  7. concentrationconcentrated
  8. customThe crude product is purified by CC on silica gel eluting with heptane:EA 1:1

Sources & evidence

ORD record
ord-5dc28c6c615c415db0844baf361e6366
Source dataset
uspto-grants-2011_08
Patent number
US08003800B2

Reaction notes

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