Phosphorus oxychloride → 6-Chloro-1,3-dimethyl-2,4(1H,3H)-pyrimidinedione

HRID 648885Notes

Reaction equation

HRID 648885 reaction equation
[CH3:1][N:2]1[C:9](=O)[CH2:8][C:6](=[O:7])[N:5]([CH3:11])[C:3]1=[O:4].P(Cl)(Cl)([Cl:14])=O>O>[Cl:14][C:9]1[N:2]([CH3:1])[C:3](=[O:4])[N:5]([CH3:11])[C:6](=[O:7])[CH:8]=1

Participants

4

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 69860Dimethylbarbituric acid

Product 1

HCID 814426-Chloro-1,3-dimethyl-2,4(1H,3H)-pyrimidinedioneYield 64%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

To 110 g of the resulting 1,3-dimethylbarbituric acid was added 32 ml of water, and 800 ml of phosphorus oxychloride was slowly added dropwise thereto. After heating at reflux for 1.5 hours, the phosphorus oxychloride was removed by distillation at normal pressure. The residue, while hot, was poured onto ice, and the thus formed crystals were collected by filtration. The filtrate was extracted three times with chloroform and dried over anhydrous sodium sulfate, followed by distillation to remove chloroform. The residue was combined with the above obtained crystals. Recrystallization from water gave 80 g (64%) of 6-chloro-1,3-dimethyluracil having a melting point of 113° to 115° C.

Workup

  1. additionwas slowly added dropwise
  2. temperatureAfter heating
  3. temperatureat reflux for 1.5 hours
  4. customthe phosphorus oxychloride was removed by distillation at normal pressure
  5. additionThe residue, while hot, was poured onto ice
  6. filtrationthe thus formed crystals were collected by filtration
  7. extractionThe filtrate was extracted three times with chloroform
  8. dry with materialdried over anhydrous sodium sulfate
  9. distillationfollowed by distillation
  10. customto remove chloroform
  11. customabove obtained crystals
  12. customRecrystallization from water

Sources & evidence

ORD record
ord-537066e31d2d4eab9bf40d6dfa5f2e30
Source dataset
uspto-grants-1988_04
Patent number
US04737442

Reaction notes

Loading…