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

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Reaction Steps

110 g of pyrocatechol were dissolved in 1500 ml of acetonitrile, and the solution was treated with 200 g of triethylamine. The mixture was treated dropwise at 75° C. with 235 g of 2,3-dichloro-1,1,1,4,4,4-hexafluoro-2-butene. Stirring was continued for 2 hours at 75° C. 1200 ml of the solvent were subsequently distilled off in vacuo, and the residue was taken up in 1500 ml of water. The product was extracted using diethyl ether, and the organic phase was washed twice using 10% strength by weight aqueous sodium hydroxide solution and once with water. After drying with magnesium sulphate, the organic phase was concentrated and subjected to fractional distillation in vacuo. 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.

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