1,2-Cyclohexanedione → 4-Oxo-4,5,6,7-tetrahydro-1-benzofuran-3-carboxylic acid

HRID 899

Reaction equation

HRID 899 reaction equation
[OH-:1].[K+].[C:3]1(=[O:10])[CH2:8][CH2:7][CH2:6][CH2:5][C:4]1=O.Br[CH2:12][C:13](=O)[C:14]([O:16]CC)=[O:15].[OH-].[Na+]>CO.O>[O:10]=[C:3]1[C:4]2[C:13]([C:14]([OH:16])=[O:15])=[CH:12][O:1][C:5]=2[CH2:6][CH2:7][CH2:8]1

Participants

7

Reactant 4

HCID 130061,2-CyclohexanedioneHCID 14797Potassium HydroxideHCID 14798Sodium HydroxideHCID 66144Ethyl bromopyruvate

Product 1

HCID 7139374-Oxo-4,5,6,7-tetrahydro-1-benzofuran-3-carboxylic acid

Reagents, catalysts & solvents 2

HCID 887MethanolSolvent3×HCID 962WaterSolvent

Conditions

Temperature
0 °C

Procedure

4-Oxo-4,5,6,7-tetrahydrobenzofuran-3-carboxylic acid was prepared as follows: To a stirred solution of potassium hydroxide (28.06 g, 0.5 mol) in methyl alcohol (100 mL) under nitrogen at 0° C. was added dropwise a solution of cyclohexanedione (56.07 g, 0.5 mol) in methyl alcohol (100 mL). The mixture was stirred at 0° C. for 0.5 h, then a solution of ethyl bromopyruvate (66 mL, 0.525 mol) in methyl alcohol(100 mL) was added dropwise. After allowing the mixture to stir at ambient temperature for 17 h, a 50% aqueous sodium hydroxide solution (60 mL) was added dropwise and stirring continued an additional 7 h. After dilution with water, the solution was acidified and the methanol removed in vacuo. Ice water was added and the precipitate filtered and dried in vacuo to afford 4-oxo-4,5,6,7-tetrahydrobenzofuran-3-carboxylic acid. m.p. 137°-138° C.

Workup

  1. custom4-Oxo-4,5,6,7-tetrahydrobenzofuran-3-carboxylic acid was prepared
  2. stirringto stir at ambient temperature for 17 h
  3. stirringstirring
  4. waitcontinued an additional 7 h
  5. customthe methanol removed in vacuo
  6. additionIce water was added
  7. filtrationthe precipitate filtered
  8. customdried in vacuo

Sources & evidence

ORD record
ord-754d50c008364ac9b11186dee1fd24b1
Source dataset
uspto-grants-1998_03
Patent number
US05723462

Linked notes

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