Sulfuric Acid → 4-Bromo-1-fluoro-2-iodobenzene

HRID 2232678Notes

Reaction equation

HRID 2232678 reaction equation
N([O-])=O.[Na+].[Br:5][C:6]1[CH:7]=[CH:8][C:9]([F:13])=[C:10]([CH:12]=1)N.S(=O)(=O)(O)O.S([O-])([O-])(=O)=O.BrC1C=CC(F)=C([N+]#N)C=1.BrC1C=CC(F)=C([N+]#N)C=1.[I-:44].[K+]>O>[Br:5][C:6]1[CH:7]=[CH:8][C:9]([F:13])=[C:10]([I:44])[CH:12]=1

Participants

7

Reactant 5

HCID 1118Sulfuric Acid2×HCID 4875Potassium IodideHCID 27694075-Bromo-2-fluoroanilineHCID 23668193Sodium NitriteHCID 85562710HCID 85562710, compound

Product 1

HCID 27827504-Bromo-1-fluoro-2-iodobenzeneYield 65%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent3×

Conditions

Temperature
22 °C

Procedure

A solution of sodium nitrite (1.71 g) in water (4 cm3) was added dropwise to a stirred mixture of 5-bromo-2fluoroaniline (4.5 g), water (15 cm3), ice (15 g) and concentrated sulphuric acid (1.8 cm3) at a temperature maintained at 0°-5° C. The reaction mixture was stirred for 30 minutes, and further concentrated sulphuric acid (0.4 cm3) added. The resultant solution, containing 5-bromo-2-fluorobenzenediazonium sulphate, was then added dropwise to a solution of potassium iodide (4.23 g) in water (10 cm3) at a temperature of 5°-6° C.; vigorous effervescence was observed during the addition. When the addition was complete, the reaction mixture was allowed to warm to the ambient temperature (22° C.) and was then extracted twice with diethyl ether. The combined extracts were washed successively with brine and sodium thiosulphate solutions, dried over anhydrous magnesium sulphate, filtered and concentrated by evaporation of the solvent under reduced pressure. The residual oil was purified by flash column chromatography, using a silica gel support and eluting with petroleum ether (boiling range 40°-60° C.) containing 4% by volume diethyl ether, to give 4-bromo-1-fluoro-2-iodobenzene (4.63 g) as a colourless oil.

Workup

  1. temperaturemaintained at 0°-5° C
  2. additionvigorous effervescence was observed during the addition
  3. additionWhen the addition
  4. extractionwas then extracted twice with diethyl ether
  5. washThe combined extracts were washed successively with brine and sodium thiosulphate solutions
  6. dry with materialdried over anhydrous magnesium sulphate
  7. filtrationfiltered
  8. concentrationconcentrated by evaporation of the solvent under reduced pressure
  9. customThe residual oil was purified by flash column chromatography
  10. washeluting with petroleum ether (boiling range 40°-60° C.)
  11. additioncontaining 4% by volume diethyl ether

Sources & evidence

ORD record
ord-cfbc8cc919eb4f65a3c4a7242bf8c0ca
Source dataset
uspto-grants-1988_11
Patent number
US04788349

Reaction notes

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