Hydrochloric Acid → 5-Methoxy-1,3-dihydro-2-benzofuran-1,3-dione

HRID 6761Notes

Reaction equation

HRID 6761 reaction equation
CO[C:3](=[O:16])[C:4]1[C:5](=[CH:10][C:11]([O:14][CH3:15])=[CH:12][CH:13]=1)[C:6]([O:8]C)=[O:7].[OH-].[Na+].Cl>CO>[CH3:15][O:14][C:11]1[CH:10]=[C:5]2[C:4](=[CH:13][CH:12]=1)[C:3](=[O:16])[O:8][C:6]2=[O:7]

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 14798Sodium HydroxideHCID 736307Dimethyl 4-methoxyphthalate

Product 1

HCID 6397485-Methoxy-1,3-dihydro-2-benzofuran-1,3-dioneYield 50.8%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

A solution of 4-methoxyphthalic acid dimethyl ester (3.1 g, Fluka, U.S.A.) in 10 mL methanol and 35 mL of a 1 M solution of aqueous sodium hydroxide was heated to reflux for 3 hours. The solution was allowed to cool to rt, acidified to pH 2 with 1 M hydrochloric acid, and extracted three times with ethyl acetate. The organic extractions were combined, dried over magnesium sulfate, and reduced in vacuo to cleanly yield 2.43 g of the corresponding diacid. The diacid (1.43 g) and 1.9 mL of acetic anhydride were dissolved in tetrahydrofuran and heated to reflux for 16 hours. The solvent was evaporated to give 5-methoxy-isobenzofuran-1,3-dione (1.25 g).

Workup

  1. temperatureto reflux for 3 hours
  2. extractionextracted three times with ethyl acetate
  3. extractionThe organic extractions
  4. dry with materialdried over magnesium sulfate
  5. dissolutionThe diacid (1.43 g) and 1.9 mL of acetic anhydride were dissolved in tetrahydrofuran
  6. temperatureheated
  7. temperatureto reflux for 16 hours
  8. customThe solvent was evaporated

Sources & evidence

ORD record
ord-714bcac5916344f08948f90775ba368f
Source dataset
uspto-grants-2006_08
Patent number
US07084154B2

Reaction notes

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