Hydrogen Bromide → 5-Bromo-2,2,3,3-tetrafluorobenzofuran

HRID 1085083Notes

Reaction equation

HRID 1085083 reaction equation
N[C:2]1[CH:3]=[CH:4][C:5]2[O:9][C:8]([F:11])([F:10])[C:7]([F:13])([F:12])[C:6]=2[CH:14]=1.N([O-])=O.[Na+].[BrH:19]>O>[Br:19][C:2]1[CH:3]=[CH:4][C:5]2[O:9][C:8]([F:11])([F:10])[C:7]([F:13])([F:12])[C:6]=2[CH:14]=1

Participants

5

Reactant 3

HCID 260Hydrogen Bromide2×HCID 137849875-Benzofuranamine, 2,2,3,3-tetrafluoro-2,3-dihydro-HCID 23668193Sodium Nitrite

Product 1

HCID 142984965-Bromo-2,2,3,3-tetrafluorobenzofuran

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Conditions

Temperature
3 °C

Procedure

A stirred mixture of 5-amino-2,2,3,3-tetrafluorobenzofuran (5.0 g, 0.024 mole) and hydrobromic acid (7.3 ml of a 48% aqueous solution) and water (10 ml) was cooled to 3° C. in an ice bath. While maintaining a temperature of less than 5° C., a solution of sodium nitrite (1.7 g, 0.024 mole) in water was added. After complete addition this mixture was stirred for a brief period, then was added slowly to a stirred, refluxing mixture of cuprous bromide (6.9 g, 0.024 mole) in hydrobromic acid (10 ml of a 48% aqueous solution). After complete addition the mixture was stirred at reflux for 20 minutes, then allowed to cool to room temperature. The reaction mixture was poured into a separatory funnel and diluted with ice water. This mixture was extracted several times with diethyl ether. The extracts were combined and washed first with 100 ml of an aqueous saturated sodium chloride solution, then with two 100 ml portions of a 2N aqueous sodium hydroxide solution. The washed organic phase was dried over anhydrous magnesium sulfate and filtered. The filtrate was evaporated at atmospheric pressure, yielding 5.9 g of 5-bromo-2,2,3,3-tetrafluorobenzofuran as an oil.

Workup

  1. temperatureWhile maintaining a temperature of less than 5° C.
  2. additionAfter complete addition this mixture
  3. additionwas added slowly to a stirred
  4. temperaturerefluxing
  5. additionAfter complete addition the mixture
  6. stirringwas stirred
  7. temperatureat reflux for 20 minutes
  8. temperatureto cool to room temperature
  9. additionThe reaction mixture was poured into a separatory funnel
  10. extractionThis mixture was extracted several times with diethyl ether
  11. washwashed first with 100 ml of an aqueous saturated sodium chloride solution
  12. dry with materialThe washed organic phase was dried over anhydrous magnesium sulfate
  13. filtrationfiltered
  14. customThe filtrate was evaporated at atmospheric pressure

Sources & evidence

ORD record
ord-5b0f04e9ffc3482396eab8e871d870a2
Source dataset
uspto-grants-1991_04
Patent number
US05008277

Reaction notes

Loading…