Quinone → 6-Methyl-1,4-naphthoquinone

HRID 1737160Notes

Reaction equation

HRID 1737160 reaction equation
[C:1]1(=[O:8])[CH:6]=[CH:5][C:4](=[O:7])[CH:3]=[CH:2]1.[CH2:9]=[CH:10][C:11](=[CH2:13])[CH3:12].[Cr](O)(O)(=O)=O>C(O)(=O)C.O>[CH3:13][C:11]1[CH:10]=[CH:9][C:3]2[C:4]([CH:5]=[CH:6][C:1](=[O:8])[C:2]=2[CH:12]=1)=[O:7]

Participants

6

Reactant 3

HCID 4650QuinoneHCID 6557IsopreneHCID 24425Chromic Acid

Product 1

HCID 5990126-Methyl-1,4-naphthoquinoneYield 31.8%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolvent2×HCID 962WaterSolvent2×

Procedure

A solution of 1,4-benzoquinone (13.9 g, 128 mmol) and isoprene (13.1 ml, 131 mmol) was stirred in glacial acetic acid (44 ml) for 68 hours at room temperature. The mixture was diluted with water (44 ml) and refluxed for 11/2 hours. The mixture was cooled to room temperature and acetic acid (84 ml) and chromic acid [chromium trioxide (29.4 g) in water (30 ml)] was added sequentially, before refluxing for a further 11/2 hours. After cooling, the mixture was diluted with water (200 ml) and extracted with ether (3×50 ml). The combined ether fractions were washed with dilute sodium hydroxide solution (2M; 2×50 ml), water (2×50 ml), saturated sodium chloride solution (50 ml) and dried over magnesium sulphate. Filtration and evaporation of solvent under reduced pressure, and repeated recrystallisation from petroleum ether yielded the title compound (7 g).

Workup

  1. temperaturerefluxed for 11/2 hours
  2. temperaturebefore refluxing for a further 11/2 hours
  3. temperatureAfter cooling
  4. extractionextracted with ether (3×50 ml)
  5. washThe combined ether fractions were washed with dilute sodium hydroxide solution (2M; 2×50 ml), water (2×50 ml), saturated sodium chloride solution (50 ml)
  6. dry with materialdried over magnesium sulphate
  7. filtrationFiltration and evaporation of solvent under reduced pressure
  8. customrecrystallisation from petroleum ether

Sources & evidence

ORD record
ord-ba68eb35deea4ddcb092aac92301e878
Source dataset
uspto-grants-1999_10
Patent number
US05962002

Reaction notes

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