Sulfuric Acid → 1,2-Difluoro-3-nitrobenzene

HRID 558939Notes

Reaction equation

HRID 558939 reaction equation
[F:1][C:2]1[C:8]([F:9])=[CH:7][CH:6]=[CH:5][C:3]=1N.[N:10]([O-:12])=[O:11].[Na+].S(=O)(=O)(O)O>F[B-](F)(F)F.[H+].O.[Cu]>[F:1][C:2]1[CH:3]=[CH:5][CH:6]=[C:7]([N+:10]([O-:12])=[O:11])[C:8]=1[F:9]

Participants

7

Reactant 3

HCID 1118Sulfuric AcidHCID 782782,3-DifluoroanilineHCID 23668193Sodium Nitrite2×

Product 1

HCID 813351,2-Difluoro-3-nitrobenzene

Reagents, catalysts & solvents 3

HCID 23978CopperCatalystHCID 962WaterSolventHCID 28118Tetrafluoroboric acidSolvent

Procedure

To a solution of 2,3-difluoroaniline (5.0 g, 38 mmol) in aqueous tetrafluoroboric acid (48%, 18 ml) was added sodium nitrite (3.9 g, 57 mmol) over 20 min while cooling in an ice/salt bath. After 1 h the mixture was filtered and washed successively with aqueous tetrafluoroboric acid and a mixture of acetone/diethyl ether (40:60). The precipitate was added to a mixture of copper (8.0 g, 121 mmol) and sodium nitrite (39 g, 570 mmol) in water (90 ml) over 20 min. After 1 h the mixture was acidified with concentrated sulphuric acid, extracted with ethyl acetate and evaporated in vacuo. The residue was purified by flash chromatography on silica (eluant EtOAc:pet. ether 20:80); yield 1.4 g (25%).

Workup

  1. temperaturewhile cooling in an ice/salt bath
  2. filtrationAfter 1 h the mixture was filtered
  3. washwashed successively with aqueous tetrafluoroboric acid
  4. additiona mixture of acetone/diethyl ether (40:60)
  5. extractionextracted with ethyl acetate
  6. customevaporated in vacuo
  7. customThe residue was purified by flash chromatography on silica (eluant EtOAc:pet. ether 20:80)

Sources & evidence

ORD record
ord-2992c3579d9141b0bc7e8de0b7d674c8
Source dataset
uspto-grants-2011_11
Patent number
US08063038B2

Reaction notes

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