Aniline → 4'-Amino-2,5-difluorobenzophenone

HRID 865761Notes

Reaction equation

HRID 865761 reaction equation
[F:1][C:2]1[CH:10]=[CH:9][C:8]([F:11])=[CH:7][C:3]=1[C:4]([OH:6])=O.[NH2:12][C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1>>[NH2:12][C:13]1[CH:18]=[CH:17][C:16]([C:4](=[O:6])[C:3]2[CH:7]=[C:8]([F:11])[CH:9]=[CH:10][C:2]=2[F:1])=[CH:15][CH:14]=1

Participants

3

Reactant 2

HCID 6115AnilineHCID 763392,5-Difluorobenzoic acid

Product 1

HCID 104897964'-Amino-2,5-difluorobenzophenoneYield 209.6%

Procedure

To stirred 90° C. polyphosphoric acid (125 g) was added 2,5-difluoro-benzoic acid (10.0 g, 6.32 mmol) and aniline (5.87 g 6.3 mmol) and the bath temperature raised to 180°-190° C. and held there for 1 hour. The heating bath was removed and the stirred mixture (sublimate above the solution) was treated cautiously with 50 mL of water. The mixture was stirred at 140°-155° C. for 1 hour, the heating bath removed, 45 mL of 3N HCl added, the mixture poured into 650 mL of water and filtered through a pad of Celite. The filtrate was basified with 15% sodium hydroxide and the mixture filtered through a pad of Celite. The Celite pad was washed well with methylene chloride, the methylene chloride dried (MgSO4), filtered and the solvent removed in vacuo. Purification by flash column chromatography (methylene chloride) followed by recrystallization twice from 50% ethanol (80 mL) yielded the aniline as a yellow solid (3.08 g, 21%); mp 101°-103° C. 1H-NMR (300 MHz, CDCl3): 4.27 (s, 2H, NH2) 6.63-6.67 (m, 2H, aromatic) 7.09-7.19 (m, 3H, aromatic) 7.68-7.71 (m, 2H, aromatic). MS (CI, CH4): 234 (M+1).

Workup

  1. temperaturethe bath temperature raised to 180°-190° C.
  2. customThe heating bath was removed
  3. additionthe stirred mixture (sublimate above the solution) was treated cautiously with 50 mL of water
  4. customthe heating bath removed
  5. addition45 mL of 3N HCl added
  6. additionthe mixture poured into 650 mL of water
  7. filtrationfiltered through a pad of Celite
  8. filtrationthe mixture filtered through a pad of Celite
  9. washThe Celite pad was washed well with methylene chloride
  10. dry with materialthe methylene chloride dried (MgSO4)
  11. filtrationfiltered
  12. customthe solvent removed in vacuo
  13. customPurification by flash column chromatography (methylene chloride)
  14. customfollowed by recrystallization twice from 50% ethanol (80 mL)

Sources & evidence

ORD record
ord-ffe44ee2b2254950bdd1cd28755a6289
Source dataset
uspto-grants-1996_10
Patent number
US05567735

Reaction notes

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