p-Toluenesulfonic acid monohydrate → 4-(2,6,6-Trimethylcyclohex-2-en-1-ylidene)but-2-en-2-yl acetate

HRID 596520

Reaction equation

HRID 596520 reaction equation
[CH3:1][C:2]1[CH2:7][CH2:6][CH2:5][C:4]([CH3:9])([CH3:8])[C:3]=1/[CH:10]=[CH:11]/[C:12]([CH3:14])=[O:13].[OH2:15].[C:16]1([CH3:26])C=CC(S(O)(=O)=O)=CC=1>C(OC(C)=C)(=O)C>[CH3:1][C:2]1[C:3](=[CH:10][CH:11]=[C:12]([O:13][C:16](=[O:15])[CH3:26])[CH3:14])[C:4]([CH3:8])([CH3:9])[CH2:5][CH2:6][CH:7]=1

Participants

4

Reactant 2

HCID 521998p-Toluenesulfonic acid monohydrateHCID 638014I2-Ionone

Product 1

HCID 534067734-(2,6,6-Trimethylcyclohex-2-en-1-ylidene)but-2-en-2-yl acetateYield 14,611.2%

Reagents, catalysts & solvents 1

HCID 7916Isopropenyl acetateSolvent

Procedure

96 g of β-ionone are dissolved in 500 ml of isopropenyl acetate and treated with 0.6 g of p-toluenesulphonic acid monohydrate. The mixture is stirred at reflux temperature under an inert gas atmosphere for 24 hours. The excess isopropenyl acetate is distilled off from the mixture under a vacuum (temperature ≤50° ) and then the mixture is treated several times with hexane in order to liberate residual amounts of isopropenyl acetate and concentrated again. In this manner, there are obtained 108 g of brown-red 4-(2,6,6-trimethyl-2-cyclohexen-1-ylidene)-2-acetoxy-but-2-ene (formula II; R = acetyl).

Workup

  1. temperatureat reflux temperature under an inert gas atmosphere for 24 hours
  2. distillationThe excess isopropenyl acetate is distilled off from the mixture under a vacuum (temperature ≤50° )
  3. additionthe mixture is treated several times with hexane in order
  4. concentrationconcentrated again

Sources & evidence

ORD record
ord-3a42c30afdab41b991655145c5e81ed9
Source dataset
uspto-grants-1977_03
Patent number
US04011245

Linked notes

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