Benzene → 2,6-Dimethoxy-4-methylidenecyclohexa-2,5-dien-1-one

HRID 2296522Notes

Reaction equation

HRID 2296522 reaction equation
[CH3:1][O:2][C:3]1[C:4](=[O:14])[C:5]([O:12][CH3:13])=[CH:6][C:7](OC)([CH3:9])[CH:8]=1.C1C=CC=CC=1.C(=O)([O-])O.[Na+]>S(=O)(=O)(O)O>[CH3:13][O:12][C:5]1[C:4](=[O:14])[C:3]([O:2][CH3:1])=[CH:8][C:7](=[CH2:9])[CH:6]=1

Participants

5

Reactant 3

HCID 241BenzeneHCID 516892Sodium BicarbonateHCID 13229516HCID 13229516, compound

Product 1

HCID 132295172,6-Dimethoxy-4-methylidenecyclohexa-2,5-dien-1-one

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Procedure

A 198 mg quantity of 2,4,6-trimethoxy-4-methyl-2,5-cyclohexadienone and 10 ml of benzene were dissolved in 10 ml of concentrated sulfuric acid, and stirred at room temperature for 2 hours. Thereafter the solution was neutralized by adding sodium hydrogen carbonate to the solution and filtered. The filtrate was concentrated at reduced pressure. The residue was extracted with dichloromethane, the solvent was removed at reduced pressure and the resulting residue was concentrated, thereby recovering 158 mg of an oily crude product. The crude product was purified by silica gel column chromatography using a 20:1 benzene-ethyl acetate mixture, giving 153 mg of 2,6-dimethoxy-4-methylidene-2,5-cyclohexadienone in 92% of theoretical yield. The compound thus obtained was identified by NMR.

Workup

  1. filtrationfiltered
  2. concentrationThe filtrate was concentrated at reduced pressure
  3. extractionThe residue was extracted with dichloromethane
  4. customthe solvent was removed at reduced pressure
  5. concentrationthe resulting residue was concentrated
  6. customrecovering 158 mg of an oily crude product
  7. customThe crude product was purified by silica gel column chromatography

Sources & evidence

ORD record
ord-8d0744d77658420cadd02b6f08e3bd90
Source dataset
uspto-grants-1984_01
Patent number
US04429164

Reaction notes

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