Quinone → 6-Methyl-1,4-naphthoquinone

HRID 1637972Notes

Reaction equation

HRID 1637972 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:12]=[C:6]2[C:5](=[CH:9][CH:10]=1)[C:4](=[O:7])[CH:3]=[CH:2][C:1]2=[O:8]

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 962WaterSolvent3×

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-d0d032edb7b54fb0943fb4e8fe5bcf1b
Source dataset
uspto-grants-2000_03
Patent number
US06043286

Reaction notes

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