Water → 3-Methyl-5-nitrobenzoic acid

HRID 1392028Notes

Reaction equation

HRID 1392028 reaction equation
[CH3:1][C:2]1[CH:3]=[C:4]([N+:9]([O-:11])=[O:10])[CH:5]=[C:6]([CH3:8])[CH:7]=1.[O-:12][Mn](=O)(=O)=O.[K+].[OH2:18]>N1C=CC=CC=1>[CH3:1][C:2]1[CH:7]=[C:6]([CH:5]=[C:4]([N+:9]([O-:11])=[O:10])[CH:3]=1)[C:8]([OH:12])=[O:18]

Participants

5

Reactant 3

HCID 962WaterHCID 74261,3-Dimethyl-5-nitrobenzeneHCID 516875Potassium Permanganate

Product 1

HCID 221685843-Methyl-5-nitrobenzoic acidYield 40%

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

Procedure

3,5-Dimethylnitrobenzene (30 g, 0.198 M) was heated with stirring to 80° in a mixture of pyridine (400 ml) and water (250 ml). KMnO4 (62.7 g, 0.396 M) was added in portions over 0.75 hours, and heating continued at 85-90° for 1.75 hours. The hot solution was filtered through celite, washing with hot water (150 ml). The pink filtrates were decolourised with a few drops of sodium metabisulfite, and evaporated to dryness. The residue was dissolved in water (250 ml), and extracted with diethyl ether (2×90 ml). The aqueous layer was acidified (concentrated hydrochloric acid), and extracted with ethyl acetate (3×120 ml). Combined organic extracts were washed with NaH2PO4 solution, brine, and dried over MgSO4. Crude product was eluted through a pad of silica, using a mixture of ethyl acetate/dichloromethane/acetic acid (25:25:1), to give 3-methyl-5-nitrobenzoic acid (14.5 g, 40%), mp 171-172°. Nmr (DHSO-d6): δ 2.51 (s, 3H); 8.17 (s, 1H); 8.30 (t, 1H); 8.42 (t, 1H); 13.58 (br, 1H).

Workup

  1. temperatureheating
  2. filtrationThe hot solution was filtered through celite
  3. washwashing with hot water (150 ml)
  4. customevaporated to dryness
  5. dissolutionThe residue was dissolved in water (250 ml)
  6. extractionextracted with diethyl ether (2×90 ml)
  7. extractionextracted with ethyl acetate (3×120 ml)
  8. washCombined organic extracts were washed with NaH2PO4 solution, brine
  9. dry with materialdried over MgSO4
  10. washCrude product was eluted through a pad of silica
  11. additiona mixture of ethyl acetate/dichloromethane/acetic acid (25:25:1)

Sources & evidence

ORD record
ord-baab8e159c014d90a616196809f7be6d
Source dataset
uspto-grants-2008_03
Patent number
US07342005B2

Reaction notes

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