Nitric Acid → 3,4-Dichloro-1,5-dimethyl-8-oxa-bicyclo[3.2.1]octa-3,6-dien-2-one

HRID 502911Notes

Reaction equation

HRID 502911 reaction equation
[Cl:1][C:2]1[C:3]2([CH3:14])[O:12][C:6]([CH3:13])([C:7](Cl)(Cl)[C:8]=1[Cl:9])[CH:5]=[CH:4]2.CCCCCC.C(OCC)(=[O:23])C.C(=O)([O-])O.[Na+].[N+]([O-])(O)=O>CC(C)=O.O.[N+]([O-])([O-])=O.[Ag+]>[Cl:9][C:8]1[C:7](=[O:23])[C:6]2([CH3:13])[O:12][C:3]([CH3:14])([C:2]=1[Cl:1])[CH:4]=[CH:5]2

Participants

7

Reactant 4

HCID 944Nitric AcidHCID 516892Sodium BicarbonateHCID 21226206Ethyl acetate hexaneHCID 586095242,3,4,4-Tetrachloro-1,5-dimethyl-8-oxabicyclo[3.2.1]octa-2,6-diene

Product 1

HCID 586095253,4-Dichloro-1,5-dimethyl-8-oxa-bicyclo[3.2.1]octa-3,6-dien-2-oneYield 54%

Reagents, catalysts & solvents 2

HCID 24470Silver NitrateCatalystHCID 18366337Propan-2-one--water (1/1)Solvent

Conditions

Temperature
67.5 °C

Procedure

14 g (51.1 mmol) of unpurified 2,3,4,4-tetrachloro-1,5-dimethyl-8-oxa-bicyclo[3.2.1]octa-2,6-diene and 17.36 g (102.2 mmol) of silver nitrate are dissolved in 500 ml of acetone/water 1:1 mixture and heated for 15 hours at a temperature of 65-70° C. until the reaction of the reactants is complete (thin-layer chromatography (TLC) monitoring (mobile phase hexane/ethyl acetate 4:1)). After the reaction mixture has cooled to ambient temperature, solid sodium hydrogen carbonate is then stirred into the mixture in portions in order to neutralise the nitric acid. The precipitated silver bromide is filtered off and most of the acetone is distilled off under reduced pressure. The aqueous phase that remains behind is extracted three times with ethyl acetate. The organic extract is washed with water, dried over sodium sulfate and concentrated by evaporation. The oily residue is purified by means of silica gel chromatography (eluant gradient: 3-50% ethyl acetate in hexane). 6.1 g (54%) of pure 3,4-dichloro-1,5-dimethyl-8-oxa-bicyclo[3.2.1]octa-3,6-dien-2-one are obtained in the form of a pale yellow solid.

Workup

  1. temperatureAfter the reaction mixture has cooled to ambient temperature
  2. filtrationThe precipitated silver bromide is filtered off and most of the acetone
  3. distillationis distilled off under reduced pressure
  4. extractionbehind is extracted three times with ethyl acetate
  5. extractionThe organic extract
  6. washis washed with water
  7. dry with materialdried over sodium sulfate
  8. concentrationconcentrated by evaporation
  9. customThe oily residue is purified by means of silica gel chromatography (eluant gradient: 3-50% ethyl acetate in hexane)

Sources & evidence

ORD record
ord-9b2d8b65ee7049f0a5e6a53ab2aa9193
Source dataset
uspto-grants-2010_08
Patent number
US07776888B2

Reaction notes

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