2-Acetyl-5-chlorothiophene → 2-Chloro-5-glyoxyloylthiophene

HRID 2260109Notes

Reaction equation

HRID 2260109 reaction equation
[Se]=[O:2].[C:3]([C:6]1[S:7][C:8]([Cl:11])=[CH:9][CH:10]=1)(=[O:5])[CH3:4]>O1CCOCC1.O>[Cl:11][C:8]1[S:7][C:6]([C:3](=[O:5])[CH:4]=[O:2])=[CH:10][CH:9]=1

Participants

5

Reactant 2

HCID 805722-Acetyl-5-chlorothiopheneHCID 167175Oxyselenide

Product 1

HCID 187887102-Chloro-5-glyoxyloylthiophene

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 312751,4-DioxaneSolvent

Procedure

Selenium oxide (6.88%) is heated to dissolve in 100 ml aqueous dioxane (95:5 dioxane: H2O). The 2-acetyl-5-chlorothiophene (5.00 g) is added to the mixture. The resulting mixture is refluxed overnight, then cooled. The precipitated selenium metal is filtered after solvent removal a brown thick oil results which solidifies on standing. The solid is heated to dissolve in 400 ml hot water, filtered and allowed to cool to room temperature. The precipitate is collected by filtration, washed with fresh H2O and dried to obtain a light brown flake. The second crop is obtained by extracting the mother liquid with ethylacetate, separated, dried (MgSO4) and concentrated in vacuo to give a light yellow solid which upon treatment with HPLC gives 2-chloro-5-glyoxyloylthiophene, which is used directly in the next step.

Workup

  1. temperatureThe resulting mixture is refluxed overnight
  2. temperaturecooled
  3. filtrationThe precipitated selenium metal is filtered
  4. customafter solvent removal a brown thick oil
  5. customresults which
  6. temperatureThe solid is heated
  7. filtrationfiltered
  8. filtrationThe precipitate is collected by filtration
  9. washwashed with fresh H2O
  10. customdried
  11. customto obtain a light brown flake
  12. customThe second crop is obtained
  13. extractionby extracting the mother liquid with ethylacetate
  14. customseparated
  15. dry with materialdried (MgSO4)
  16. concentrationconcentrated in vacuo
  17. customto give a light yellow solid which upon treatment with HPLC

Sources & evidence

ORD record
ord-4a2faf2158644582909d71686186b48b
Source dataset
uspto-grants-1995_12
Patent number
US05476851

Reaction notes

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