Water → 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic Acid

HRID 1359667Notes

Reaction equation

HRID 1359667 reaction equation
C([O:3][C:4](=[O:9])[CH2:5][C:6](=O)[CH3:7])C.C([O:14][C:15](=O)[C:16](=[N:20]O)[C:17](=O)[CH3:18])(C)(C)C.O>C(O)(=O)C.[Zn]>[CH:15]([C:16]1[NH:20][C:6]([CH3:7])=[C:5]([C:4]([OH:3])=[O:9])[C:17]=1[CH3:18])=[O:14]

Participants

6

Reactant 3

HCID 962WaterHCID 8868Ethyl AcetoacetateHCID 178468384tert-butyl 2-hydroxyimino-3-oxobutanoate

Product 1

HCID 110737925-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic Acid

Reagents, catalysts & solvents 2

HCID 23994ZincCatalyst2×HCID 176Acetic AcidSolvent

Conditions

Temperature
60 °C

Procedure

Ethyl-3-oxobutyrate (130 g, 1 mol) was dissolved in 400 mL of acetic acid in a 2 L 3-neck round bottom flask equipped with a thermometer, an addition funnel, mechanical stirring and placed in an oil bath. Zinc dust (50 g, 0.76 mol) was added and the mixture heated to 60° C. with stirring. The crude t-butyl-2-hydroximino-3-oxobutyrate solution prepared above was cautiously added keeping the temperature at about 65° C. by slowing the addition and cooling the flask. More zinc dust (4×50 g, 3.06 mol) was added in portions during the addition with the last portion added after all the t-butyl ester had been added. The temperature of the mixture reached a maximum of 80° C. At the end of the additions the temperature was 64° C. The temperature was increased by heating to 70-75° C. for one hour and then poured into 5 L of water. The gray floating precipitate was collected by vacuum filtration and washed with 2 L of water to give 354 g of wet crude product. The crude product was dissolved in 1 L of hot methanol and hot filtered to remove zinc. The filtrate was cooled to give a precipitate that was collected by vacuum filtration to give 118 g of product. The filtrate was put in the refrigerator overnight to give a total of 173.2 g of

Workup

  1. customequipped with a thermometer, an addition funnel
  2. customplaced in an oil bath
  3. stirringwith stirring
  4. additionabove was cautiously added
  5. customat about 65° C.
  6. additionthe addition
  7. temperaturecooling the flask
  8. additionhad been added
  9. customa maximum of 80° C
  10. customwas 64° C
  11. temperatureThe temperature was increased
  12. temperatureby heating to 70-75° C. for one hour
  13. filtrationwas collected by vacuum filtration
  14. washwashed with 2 L of water

Sources & evidence

ORD record
ord-138d5a112ae949aaa218b20bbc2e575c
Source dataset
uspto-grants-2003_07
Patent number
US06599902B2

Reaction notes

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