5-Fluorouracil → 5-Fluoro-4-thiouracil

HRID 1380286Notes

Reaction equation

HRID 1380286 reaction equation
[F:1][C:2]1[C:3](=O)[NH:4][C:5](=[O:8])[NH:6][CH:7]=1.P12(SP3(SP(SP(S3)(S1)=S)(=S)S2)=S)=[S:11]>O1CCOCC1>[F:1][C:2]1[C:3](=[S:11])[NH:4][C:5](=[O:8])[NH:6][CH:7]=1

Participants

4

Reactant 2

HCID 33855-FluorouracilHCID 14817Phosphorus sulfide (P2S5)

Product 1

HCID 27812135-Fluoro-4-thiouracilYield 144.8%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

A mixture of 5-fluorouracil (26 g, 0.12 mole) and phosphorus pentasulfide (45 g, 0.2 mole) in 500 mL dioxane was heated under reflux for 3 hr. The hot reaction mixture was filtered and concentrated in vacuo. The residue was dissolved in 650 mL water, heated with 5 g charcoal and filtered. The solid which crystallized on cooling was collected by filtration to yield 25.4 g (88%) of 5-fluoro-4-thiouracil, m.p. 269°-272° C.

Workup

  1. temperaturewas heated
  2. temperatureunder reflux for 3 hr
  3. filtrationThe hot reaction mixture was filtered
  4. concentrationconcentrated in vacuo
  5. dissolutionThe residue was dissolved in 650 mL water
  6. temperatureheated with 5 g charcoal
  7. filtrationfiltered
  8. customThe solid which crystallized
  9. temperatureon cooling
  10. filtrationwas collected by filtration

Sources & evidence

ORD record
ord-d25a265ec5c54c46b50db7f3e2c72be2
Source dataset
uspto-grants-1986_04
Patent number
US04581357

Reaction notes

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