Ethanol → Dimethylbarbituric acid

HRID 542706Notes

Reaction equation

HRID 542706 reaction equation
[CH3:1][NH:2][C:3]([NH:5][CH3:6])=[O:4].[C:7]([OH:13])(=O)[CH2:8][C:9]([OH:11])=O.C(OC(=O)C)(=O)C.C(O)C>C(O)(=O)C>[CH3:1][N:2]1[C:7](=[O:13])[CH2:8][C:9](=[O:11])[N:5]([CH3:6])[C:3]1=[O:4]

Participants

6

Reactant 4

HCID 702EthanolHCID 867Malonic AcidHCID 7293N,N'-DimethylureaHCID 7918Acetic Anhydride

Product 1

HCID 69860Dimethylbarbituric acidYield 73.4%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

That is, 276 g (3.14 moles) of 1,3-dimethylurea and 376 g (3.62 moles) of malonic acid were dissolved in 600 ml of glacial acetic acid at 60° to 70° C., and then, after adding thereto 1250 ml of acetic anhydride, the temperature of the mixture was gradually increased to 90° C. Then, after stirring the mixture for 6 hours at the same temperature, the reaction mixture was allowed to stand overnight at room temperature and glacial acetic acid and acetic anhydride were distilled off under reduced pressure. The residue thus formed was added to 500 ml of ethanol while still hot and the crystals thus precipitated were collected by filtration, heat-refluxed for 2 hours with 380 ml of concentrated hydrochloric acid and 400 ml of water, and then allowed to stand for 6 hours under ice-cooling. The crystals thus precipitated were collected by filtration and washed with a small amount of ethanol to provide 360 g of 1,3-dimethylbarbituric acid.

Workup

  1. additionafter adding
  2. waitto stand overnight at room temperature
  3. distillationglacial acetic acid and acetic anhydride were distilled off under reduced pressure
  4. customThe residue thus formed
  5. customthus precipitated
  6. filtrationwere collected by filtration
  7. temperatureheat-refluxed for 2 hours with 380 ml of concentrated hydrochloric acid and 400 ml of water
  8. waitto stand for 6 hours under ice-
  9. temperaturecooling
  10. customThe crystals thus precipitated
  11. filtrationwere collected by filtration
  12. washwashed with a small amount of ethanol

Sources & evidence

ORD record
ord-94b7da69abf648ce86c9c948aefb06d4
Source dataset
uspto-grants-1987_04
Patent number
US04659651

Reaction notes

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