Potassium Permanganate → 2,4,5-Trimethoxybenzaldehyde

HRID 413554Notes

Reaction equation

HRID 413554 reaction equation
[CH3:1][O:2][C:3]1[CH:12]=[C:11]([O:13][CH3:14])[C:10]([O:15][CH3:16])=[CH:9][C:4]=1[CH:5]=CC=O.[O-:17][Mn](=O)(=O)=O.[K+]>CC(C)=O>[CH3:1][O:2][C:3]1[CH:12]=[C:11]([O:13][CH3:14])[C:10]([O:15][CH3:16])=[CH:9][C:4]=1[CH:5]=[O:17]

Participants

4

Reactant 2

HCID 516875Potassium PermanganateHCID 540454412,4,5-Trimethoxy cinnamaldehyde

Product 1

HCID 205252,4,5-TrimethoxybenzaldehydeYield 45.3%

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

A solution of the 2,4,5-Trimethoxycinnamaldehyde (0.5 g) was treated with KMnO4 (0.5 g) in dry acetone (20 ml). The reaction mixture was left at room temperature for 24 hr, manganese dioxide was filtered off and the solvent was removed. The residue was dissolved in ethyl acetate and washed carefully with 10% NaHCO3, brine, and dried over anhydrous Na2SO4. Evaporation of the solvent afforded a crude solid, which was further recrystallised from water to afford 0.2 g 2,4,5-trimethoxybenzaldehyde as a colorless solid, mp 114° C. (lit. mp 114° C.); IR (film) νmax 1662 (carbonyl group), 1620, 1518, 1481, 1419, 1361, 1300, 1278, 1222, 1199, 1138, 1025, 865 cm−1; 1H NMR δ 10.32 (1H, s, CHO), 7.33 (1H, s, 6H), 6.50 (1H, s, 3H), 3.98 (3H, s, 2-OCH3), 3.93 ((3H, s, 4-OCH3), 3.88 (3H, s, 5-OCH3); 13C NMR δ 187.96 (CHO), 158.60 (C-2), 155.76 (C-4), 143.56 (C-5), 117.35 (C-1), 109.03 (C-6), 56.19 (2-OCH3, 4-OCH3 and 5-OCH3); EIMS m/z 196 [M]+ (100), 181 (49), 150 (32), 125 (33), 110 (23), 69 (37).

Workup

  1. filtrationmanganese dioxide was filtered off
  2. customthe solvent was removed
  3. dissolutionThe residue was dissolved in ethyl acetate
  4. washwashed carefully with 10% NaHCO3, brine
  5. dry with materialdried over anhydrous Na2SO4
  6. customEvaporation of the solvent
  7. customafforded a crude solid, which
  8. customwas further recrystallised from water

Sources & evidence

ORD record
ord-800784b050a942f7b29119eb4c21d45d
Source dataset
uspto-grants-2003_05
Patent number
US06566557B2

Reaction notes

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