Phosphorus pentachloride → 5-Acetylamino-7,8-difluoro-1-tetralone

HRID 2257876Notes

Reaction equation

HRID 2257876 reaction equation
[C:1]([NH:4][C:5]1[CH:10]=[C:9]([F:11])[C:8]([F:12])=[CH:7][C:6]=1[CH2:13][CH2:14][CH2:15][C:16]([OH:18])=O)(=[O:3])[CH3:2].P(Cl)(Cl)(Cl)(Cl)Cl>ClCCl>[C:1]([NH:4][C:5]1[CH:10]=[C:9]([F:11])[C:8]([F:12])=[C:7]2[C:6]=1[CH2:13][CH2:14][CH2:15][C:16]2=[O:18])(=[O:3])[CH3:2]

Participants

4

Reactant 2

HCID 24819Phosphorus pentachlorideHCID 105872254-(2-Acetylamino-4,5-difluorophenyl)butanoic acid

Product 1

HCID 224495485-Acetylamino-7,8-difluoro-1-tetralone

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

The compound obtained in (4) above (9.07 gm) was dissolved into 450 ml of dichloromethane. To the mixture was added 7.71 gm of phosphorous pentachloride while stirring at room temperature. After stirring for a further 1 hour, the reaction mixture was concentrated and dichloromethane was added to the residue. Dichloromethane was evaporated again and 500 ml of 1,2-dichloroethane and 9.88 gm of anhydrous aluminum chloride were added to the residue. The mixture was stirred for 1 hour at 70° C. and gently heated under reflux for 15 hours. The reaction product was poured into ice-cold water, extracted with chloroform, washed with saturated brine, and dried over anhydrous sodium sulfate. The solvent was evaporated and the residue was subjected to silica gel column chromatography using chloroform-methanol (50:1) as an eluant to obtain fractions containing the target compound. The fractions were concentrated to obtain 2.31 gm of the title compound.

Workup

  1. stirringAfter stirring for a further 1 hour
  2. concentrationthe reaction mixture was concentrated
  3. additiondichloromethane was added to the residue
  4. customDichloromethane was evaporated again
  5. addition500 ml of 1,2-dichloroethane and 9.88 gm of anhydrous aluminum chloride were added to the residue
  6. stirringThe mixture was stirred for 1 hour at 70° C.
  7. temperaturegently heated
  8. temperatureunder reflux for 15 hours
  9. additionThe reaction product was poured into ice-cold water
  10. extractionextracted with chloroform
  11. washwashed with saturated brine
  12. dry with materialdried over anhydrous sodium sulfate
  13. customThe solvent was evaporated
  14. customto obtain fractions
  15. additioncontaining the target compound
  16. concentrationThe fractions were concentrated

Sources & evidence

ORD record
ord-7d2ca3cc22064a5ca09688af3b487704
Source dataset
uspto-grants-1997_08
Patent number
US05658920

Reaction notes

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