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

HRID 2083120Notes

Reaction equation

HRID 2083120 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 inch Goodloe column to yield 257 g of product, b.p. 92° 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 inch Goodloe column

Sources & evidence

ORD record
ord-a35095daea814c93a9db2f4e78160355
Source dataset
uspto-grants-1978_04
Patent number
US04084009

Reaction notes

Loading…