Acetic Anhydride → 1,4-Naphthalenedione, 2-(acetyloxy)-

HRID 1176938Notes

Reaction equation

HRID 1176938 reaction equation
C(N(CC)CC)C.[OH:8][C:9]1[C:10](=[O:20])[C:11]2[C:16]([C:17](=[O:19])[CH:18]=1)=[CH:15][CH:14]=[CH:13][CH:12]=2.[C:21](OC(=O)C)(=[O:23])[CH3:22]>C(OCC)(=O)C>[C:21]([O:8][C:9]1[C:10](=[O:20])[C:11]2[C:16]([C:17](=[O:19])[CH:18]=1)=[CH:15][CH:14]=[CH:13][CH:12]=2)(=[O:23])[CH3:22]

Participants

5

Reactant 3

HCID 7918Acetic AnhydrideHCID 8471TriethylamineHCID 178516607HCID 178516607, compound

Product 1

HCID 745131,4-Naphthalenedione, 2-(acetyloxy)-Yield 80%

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Procedure

595 g (5.89 moles) of triethylamine are added dropwise in 30 minutes to a suspension of 500 g (2.87 moles) of 2-hydroxy-1,4-naphthoquinone (lawsone) in 2200 ml of ethyl acetate, cooled to +5° C., maintaining the temperature below +10° C. At the end of the dripping a dark red solution is obtained. The solution is kept at +5-10° C. for 30 minutes. 550 g (5.39 moles) of acetic anhydride are added dropwise in 30 minutes, maintaining the temperature between +5 and +10° C. At the end of the dripping, the mixture is left under agitation at +5° C. for 4 hours. The solid is filtered and washed with a mixture of 250 ml of ethyl acetate and 250 ml of hexane pre-cooled to +5° C. The damp product is dried at +40° C. at reduced pressure for 6 hours providing 496 g (yield 80%) of 2-acetoxy-1,4-naphthoquinone (acetyl-lawsone) as a yellow solid with melting point −131°-134° C.

Workup

  1. temperaturecooled to +5° C.
  2. temperaturemaintaining the temperature below +10° C
  3. customAt the end of the dripping a dark red solution is obtained
  4. temperaturemaintaining the temperature between +5 and +10° C
  5. waitAt the end of the dripping, the mixture is left under agitation at +5° C. for 4 hours
  6. filtrationThe solid is filtered
  7. washwashed with a mixture of 250 ml of ethyl acetate and 250 ml of hexane
  8. temperaturepre-cooled to +5° C
  9. customThe damp product is dried at +40° C. at reduced pressure for 6 hours

Sources & evidence

ORD record
ord-017f9cb14ad44b5fba3bfe73d60189d9
Source dataset
uspto-grants-2010_11
Patent number
US07842840B2

Reaction notes

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