HCID 23468823, compound → HCID 23468845, compound

HRID 128307Notes

Reaction equation

HRID 128307 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:11]=[CH:12][C:13]=1[O:14][CH:15]([CH3:19])[C:16](=O)[CH3:17])[C:6]([O:8][CH2:9][CH3:10])=[O:7]>S(=O)(=O)(O)O>[CH3:19][C:15]1[O:14][C:13]2[C:3]([O:2][CH3:1])=[CH:4][C:5]([C:6]([O:8][CH2:9][CH3:10])=[O:7])=[CH:11][C:12]=2[C:16]=1[CH3:17]

Participants

3

Reactant 1

HCID 23468823HCID 23468823, compound

Product 1

HCID 23468845HCID 23468845, compound

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Procedure

1,600 ml of 70% sulfuric acid are added to 214 g (0.8 mol) of ethyl 3-methoxy-4-(1-methyl-2-oxopropoxy)-benzoate at room temperature. During this addition, the reaction mixture becomes dark-red to brown in colour. Thereafter, the reaction mixture is warmed to 60° for 4 hours. A brown crystalline sludge thereby gradually forms. The reaction mixture is allowed to cool to room temperature and is poured onto 2 kg of ice and extracted with ethyl acetate. The extract is washed twice with water and then 5 times with 500 ml of 0.5 N sodium bicarbonate solution each time and 3 times with 500 ml of 2 N sodium carbonate solution each time, dried over magnesium sulfate and evaporated completely under a waterpump vacuum. Chromatography on 1.5 kg of silica gel using chloroform which contains 2% of methanol gives ethyl 2,3-dimethyl-7-methoxy-5-benzofurancarboxylate, which, after recrystallisation from warm hexane, melts at 67°-68°.

Workup

  1. additionDuring this addition
  2. temperatureThereafter, the reaction mixture is warmed to 60° for 4 hours
  3. extractionextracted with ethyl acetate
  4. washThe extract is washed twice with water
  5. dry with material5 times with 500 ml of 0.5 N sodium bicarbonate solution each time and 3 times with 500 ml of 2 N sodium carbonate solution each time, dried over magnesium sulfate
  6. customevaporated completely under a waterpump vacuum

Sources & evidence

ORD record
ord-3dd75e9db54f4cf98aab5064a8e974d6
Source dataset
uspto-grants-1981_03
Patent number
US04259338

Reaction notes

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