Ethyl 5-methyl-2-oxo-2,3-dihydro-1H-imidazole-4-carboxylate → ethyl 1,3-diacetyl-2,3-dihydro-5-methyl-2-oxo-1H-imidazole-4-carboxylate

HRID 1758128Notes

Reaction equation

HRID 1758128 reaction equation
[CH3:1][C:2]1[NH:6][C:5](=[O:7])[NH:4][C:3]=1[C:8]([O:10][CH2:11][CH3:12])=[O:9]>C(OC(=O)C)(=O)C>[C:8]([N:6]1[C:2]([CH3:1])=[C:3]([C:8]([O:10][CH2:11][CH3:12])=[O:9])[N:4]([C:11](=[O:10])[CH3:12])[C:5]1=[O:7])(=[O:9])[CH3:3]

Participants

3

Reactant 1

HCID 222231Ethyl 5-methyl-2-oxo-2,3-dihydro-1H-imidazole-4-carboxylate

Product 1

HCID 12850292ethyl 1,3-diacetyl-2,3-dihydro-5-methyl-2-oxo-1H-imidazole-4-carboxylate

Reagents, catalysts & solvents 1

HCID 7918Acetic AnhydrideSolvent

Procedure

A mixture of 54.5 g of ethyl 2,3-dihydro-5-methyl-2-oxo-1H-imidazole-4-carboxylate and 240 ml of acetic anhydride is refluxed for 13 hours. The mixture is distilled to remove 150 ml of acetic anhydride and acetic acid; this is replaced by fresh acetic anhydride and refluxing is resumed. After a total of 22 hours of reflux, excess acetic anhydride is evaporated under reduced pressure and the resulting residue is triturated with cyclohexane and then recrystallized from cyclohexane to give ethyl 1,3-diacetyl-2,3-dihydro-5-methyl-2-oxo-1H-imidazole-4-carboxylate melting at about 56°-58° C.

Workup

  1. temperatureis refluxed for 13 hours
  2. distillationThe mixture is distilled
  3. customto remove 150 ml of acetic anhydride and acetic acid
  4. temperaturerefluxing
  5. temperatureAfter a total of 22 hours of reflux
  6. customexcess acetic anhydride is evaporated under reduced pressure
  7. customthe resulting residue is triturated with cyclohexane
  8. customrecrystallized from cyclohexane

Sources & evidence

ORD record
ord-9ee16410903240d387d5dbf9e2dca293
Source dataset
uspto-grants-1983_02
Patent number
US04371737

Reaction notes

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