Sulfuric Acid → Tert-butyl 3,5-difluorobenzoate

HRID 1243279Notes

Reaction equation

HRID 1243279 reaction equation
[F:1][C:2]1[CH:3]=[C:4]([CH:8]=[C:9]([F:11])[CH:10]=1)[C:5]([OH:7])=[O:6].S(=O)(=O)(O)O.[CH2:17]=[C:18]([CH3:20])[CH3:19]>C(Cl)Cl.O1CCOCC1>[C:18]([O:6][C:5](=[O:7])[C:4]1[CH:3]=[C:2]([F:1])[CH:10]=[C:9]([F:11])[CH:8]=1)([CH3:20])([CH3:19])[CH3:17]

Participants

6

Reactant 3

HCID 1118Sulfuric AcidHCID 8255IsobutyleneHCID 1012653,5-Difluorobenzoic acid

Product 1

HCID 21925017Tert-butyl 3,5-difluorobenzoateYield 81%

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 312751,4-DioxaneSolvent

Procedure

3,5-Difluorobenzoic acid (25 g, 0.158 mol) was dissolved in DCM (150 mL) and dioxane (50 mL). The mixture was transferred into a stainless steel autoclave. Concentrated sulfuric acid (3.6 mL) was added, followed by isobutene (100 mL). The mixture was kept in the autoclave for 5 days. Excess isobutene and the solvents were removed under reduced pressure, the mixture diluted with EtOAc and washed with water, saturated aqueous sodium hydrogen carbonate and brine. Drying and evaporation gave a dark-yellow oil, which was purified by kugelrohr distillation (80–100° C., 1.0 mbar) to give tert-butyl-3,5-difluorobenzoate (27.51, g, 81% ) as a colorless solid.

Workup

  1. customExcess isobutene and the solvents were removed under reduced pressure
  2. additionthe mixture diluted with EtOAc
  3. washwashed with water, saturated aqueous sodium hydrogen carbonate and brine
  4. customDrying
  5. customevaporation
  6. customgave a dark-yellow oil, which
  7. distillationwas purified by kugelrohr distillation (80–100° C., 1.0 mbar)

Sources & evidence

ORD record
ord-29e9ecda590e4ac59c8fab8a1c360fb2
Source dataset
uspto-grants-2006_10
Patent number
US07119073B2

Reaction notes

Loading…