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

HRID 2069398Notes

Reaction equation

HRID 2069398 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 78%

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent2×

Procedure

4-Benzyloxy-3-ethyl-5-methyl-benzaldehyde (1.4 g, 5.5 mmol) is dissolved in acetone (20 mL) and is slowly added to a cold solution of KMnO4 (1.74 g, 11 mmol) in 20% aq. acetone (25 mL). The reaction mixture is stirred at rt for 3 h, and then acetone is evaporated. The remaining aq. phase is acidified with 10% citric acid (60 mL) and is extracted with DCM (80 mL, 60 mL, 60 mL). The combined org. extracts are washed with brine, dried over MgSO4, filtered and evaporated. The crude product is purified by CC on silica gel eluting with heptane:EA (5:1 to 2:1) to give 4-benzyloxy-3-ethyl-5-methyl-benzoic acid (1.16 g) as an off-white solid; LC-MS: tR=0.56 min*; 1H NMR (CDCl3): δ 1.29 (t, J=7.5 Hz, 3H), 2.39 (s, 3H), 2.75 (q, J=7.5 Hz, 2H), 4.90 (s, 2H), 7.53-7.36 (m, 5H), 7.86 (s, 1H), 7.89 (s, 1H), 12.0 (s br, 1H).

Workup

  1. customacetone is evaporated
  2. extractionis extracted with DCM (80 mL, 60 mL, 60 mL)
  3. washextracts are washed with brine
  4. dry with materialdried over MgSO4
  5. filtrationfiltered
  6. customevaporated
  7. customThe crude product is purified by CC on silica gel eluting with heptane:EA (5:1 to 2:1)

Sources & evidence

ORD record
ord-2d73f23dec5744d08e0ef803385b142d
Source dataset
uspto-grants-2012_10
Patent number
US08299086B2

Reaction notes

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