Benzene → 2,7,9,9-Tetramethyl-1,4-dioxaspiro[4,5]dec-6-en-8-one

HRID 262355Notes

Reaction equation

HRID 262355 reaction equation
[CH3:1][C:2]1[C:3](=[O:11])[C:4]([CH3:10])([CH3:9])[CH2:5][C:6](=[O:8])[CH:7]=1.[CH2:12]([OH:16])[CH:13](O)[CH3:14].C1C=CC=CC=1>C1(C)C=CC(S(O)(=O)=O)=CC=1.O>[CH3:14][CH:13]1[CH2:12][O:16][C:6]2([CH2:5][C:4]([CH3:10])([CH3:9])[C:3](=[O:11])[C:2]([CH3:1])=[CH:7]2)[O:8]1

Participants

6

Reactant 3

HCID 241BenzeneHCID 1030Propylene GlycolHCID 62374Ketoisophorone

Product 1

HCID 132091832,7,9,9-Tetramethyl-1,4-dioxaspiro[4,5]dec-6-en-8-oneYield 80%

Reagents, catalysts & solvents 2

HCID 6101p-Toluenesulfonic acidCatalystHCID 962WaterSolvent2×

Procedure

To a 2-liter flask fitted with a reflux condenser, a water separator and a stirrer is charged 265 g of 2,6,6-trimethylcyclohex-2-en-1,4-dione (prepared by the method described in Helv. Chim. Acta, 39:2041 [1956]), 266 g of propylene glycol, 500 ml of benzene and 1 g of p-toluenesulfonic acid. The reactants are stirred and refluxed until no additional water is collected in the water separator. The product is washed with water to a pH of 6, and the solvent is stripped off. The residue is vacuum distilled through a 9" Goodloe column to yield 257 g of product, boiling point 92° C. at 1 mm Hg (80% yield).

Workup

  1. customTo a 2-liter flask fitted with a reflux condenser
  2. customprepared by the method
  3. customis collected in the water separator
  4. washThe product is washed with water to a pH of 6
  5. distillationdistilled through a 9" Goodloe column

Sources & evidence

ORD record
ord-3447f49ecfa9453d9c8cb63983b188e9
Source dataset
uspto-grants-1979_05
Patent number
US04154696

Reaction notes

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