Reaction #65845

Reaction equation

pyrocatechol

triethylamine

2,3-dichloro-1,1,1,4,4,4-hexafluorobut-2-ene

→

2-(1-Chloro-2,2,2-trifluoroethyl)-2-trifluoromethyl-1,3-benzodioxole

Solvents

acetonitrile

Conditions

Workup

1. 1
   workup.DISTILLATION1200 ml of the solvent were then distilled off under vacuum
2. 2
   ExtractionThe product was extracted with diethyl ether
3. 3
   Washthe organic phase was washed twice with 10% by Weight aqueous sodium hydroxide solution and once with water
4. 4
   DryingAfter drying over magnesium sulphate
5. 5
   Concentrationthe solution was concentrated
6. 6
   workup.DISTILLATIONsubjected to fractional distillation under vacuum

Procedure

110 g of pyrocatechol were dissolved in 1500 ml of acetonitrile, and 200 g of triethylamine were added. 235 g of 2,3-dichloro-1,1,1,4,4,4-hexafluorobut-2-ene were added dropwise to the mixture at 75° C. The reaction mixture was subsequently stirred for 2 hours at 75° C. 1200 ml of the solvent were then distilled off under vacuum and the residue was taken up in 1500 ml of water. The product was extracted with diethyl ether and the organic phase was washed twice with 10% by Weight aqueous sodium hydroxide solution and once with water. After drying over magnesium sulphate, the solution was concentrated and subjected to fractional distillation under vacuum. The yield was 258 g (=84% of theory). The boiling point was 63° C. at 12 mbar. The NMR spectra showed the following characteristic absorptions: 19F NMR: -66.8 and -79.7 ppm. 1H NMR: 4.71 ppm.

Source