1,2-Dibromoethane → 2,2,3,3,5,6-Hexafluoro-2,3-dihydro-1,4-dioxine

HRID 1494496Notes

Reaction equation

HRID 1494496 reaction equation
BrCCBr.Cl[C:6]1([F:18])[C:11](Cl)([F:12])[O:10][C:9]([F:15])([F:14])[C:8]([F:17])([F:16])[O:7]1>CN(C=O)C.[Zn]>[F:15][C:9]1([F:14])[C:8]([F:16])([F:17])[O:7][C:6]([F:18])=[C:11]([F:12])[O:10]1

Participants

5

Reactant 2

HCID 78391,2-DibromoethaneHCID 14912591HCID 14912591, compound

Product 1

HCID 149125932,2,3,3,5,6-Hexafluoro-2,3-dihydro-1,4-dioxineYield 45.1%

Reagents, catalysts & solvents 2

HCID 23994ZincCatalystHCID 6228DimethylformamideSolvent

Procedure

A suspension of 39.2 g (0.60 mol) of zinc dust in 300 mL of dry DMF was stirred under N2 while 5 mL of 1,2-dibromoethane was added. Then a small portion of 74.0 g (0.28 mol) of dichloride 5 was added, and the mixture was stirred and heated. When an exothermic reaction started (about 75° C.), the rest of 5 was added dropwise at a rate sufficient to maintain 110°-120° C. in the pot while product was collected in a -80° C. trap. When the addition was completed, the mixture was heated to reflux to drive out the last of the product. Fractionation of the crude volatile product gave 24.5 g (45%) of pure perfluoro-2,3-dihydro-1,4-dioxin (7), bp 18°-19.5° C. IR (gas): 1845 cm-1 (w, C=C).

Workup

  1. additionwas added
  2. temperatureheated
  3. customWhen an exothermic reaction
  4. custom(about 75° C.)
  5. additionthe rest of 5 was added dropwise at a rate sufficient
  6. temperatureto maintain 110°-120° C. in the pot while product
  7. customwas collected in a -80° C. trap
  8. additionWhen the addition
  9. temperaturethe mixture was heated
  10. temperatureto reflux

Sources & evidence

ORD record
ord-f3c44ad1eee7419ab86e07103a521c1b
Source dataset
uspto-grants-1991_06
Patent number
US05026801

Reaction notes

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