Acetic Anhydride → o-Methylcinnamic acid

HRID 1645904Notes

Reaction equation

HRID 1645904 reaction equation
[C:1]1([CH3:9])[C:2]([CH:7]=O)=[CH:3][CH:4]=[CH:5][CH:6]=1.[C:10]([O:13]C(=O)C)(=[O:12])[CH3:11].C([O-])(=O)C.[K+]>>[CH3:9][C:1]1[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=1/[CH:7]=[CH:11]/[C:10]([OH:13])=[O:12]

Participants

4

Reactant 3

HCID 7918Acetic AnhydrideHCID 107222-MethylbenzaldehydeHCID 517044Potassium Acetate

Product 1

HCID 819020o-Methylcinnamic acidYield 35.1%

Procedure

A mixture of 35.1 g (0.29 mol) of o-tolualdehyde, 47.6 g (0.46 mol) of acetic anhydride, and 18 g (0.174 mol) of fused and pulverized potassium acetate was heated at 155°-160° for 15 minutes and then at 165°-170° for 12 hours. The mixture was diluted with 1 liter of ice water and steam distilled to remove excess aldehyde. On cooling, a yellow solid formed. The solid was collected, washed with water, dissolved in chloroform, treated with charcoal, and filtered. The filtrate was concentrated and the residue was recrystallized from ethanol/ether to give 16.5 g (35%) of trans-2-methylcinnamic acid; mp 173°-175°.

Workup

  1. temperaturewas heated at 155°-160° for 15 minutes
  2. distillationdistilled
  3. customto remove excess aldehyde
  4. temperatureOn cooling
  5. customa yellow solid formed
  6. customThe solid was collected
  7. washwashed with water
  8. dissolutiondissolved in chloroform
  9. additiontreated with charcoal
  10. filtrationfiltered
  11. concentrationThe filtrate was concentrated
  12. customthe residue was recrystallized from ethanol/ether

Sources & evidence

ORD record
ord-da14a86d1f84468b89579bb284153ec9
Source dataset
uspto-grants-1993_01
Patent number
US05177075

Reaction notes

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