Potassium Permanganate → 2,3-Dimethoxy-6-nitrobenzoic acid

HRID 980876Notes

Reaction equation

HRID 980876 reaction equation
[CH3:1][O:2][C:3]1[C:10]([O:11][CH3:12])=[CH:9][CH:8]=[C:7]([N+:13]([O-:15])=[O:14])[C:4]=1[CH:5]=[O:6].[Mn]([O-])(=O)(=O)=[O:17].[K+]>CC(C)=O>[CH3:1][O:2][C:3]1[C:10]([O:11][CH3:12])=[CH:9][CH:8]=[C:7]([N+:13]([O-:15])=[O:14])[C:4]=1[C:5]([OH:17])=[O:6]

Participants

4

Reactant 2

HCID 516875Potassium PermanganateHCID 71721272,3-Dimethoxy-6-nitrobenzaldehyde

Product 1

HCID 127623792,3-Dimethoxy-6-nitrobenzoic acid

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

2,3-Dimethoxy-6-nitrobenzaldehyde from Example 6 (331 g) was added to acetone (2.5 1) in a 12 1 flask. A saturated solution (approximately 60-65 g/ 1) of potassium permanganate was added until TLC showed no starting material. Approximately 7 1 was required. The reaction mixture was filtered to remove the MnO2 and was washed with 2.5N KOH and acetone (2 1 each). The combined filtrates were evaporated to dryness and acidified with concentrated HCl. The precipitated solid was collected on a filter, washed with water (250 ml) and dried overnight. The solid was dissolved in 2 1 acetone, treated with MgSO4 and charcoal, evaporated to 500 ml and cooled to 5°. The crystals were filtered, washed with acetone and hexane and dried to afford dimethoxy acid (234 g, 65.7%) mp 187°-189° C.

Workup

  1. filtrationThe reaction mixture was filtered
  2. customto remove the MnO2
  3. washwas washed with 2.5N KOH and acetone (2 1 each)
  4. customThe combined filtrates were evaporated to dryness
  5. customThe precipitated solid was collected on a filter
  6. washwashed with water (250 ml)
  7. customdried overnight
  8. dissolutionThe solid was dissolved in 2 1 acetone
  9. additiontreated with MgSO4 and charcoal
  10. customevaporated to 500 ml
  11. temperaturecooled to 5°
  12. filtrationThe crystals were filtered
  13. washwashed with acetone and hexane
  14. customdried
  15. customto afford dimethoxy acid (234 g, 65.7%) mp 187°-189° C.

Sources & evidence

ORD record
ord-86ba2d833341420cb4822a2ac73d52c2
Source dataset
uspto-grants-1987_01
Patent number
US04639518

Reaction notes

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