m-Chloroperbenzoic acid → 2-(1-Chloro-2,2,2-trifluoroethyl)-2-(trifluoromethyl)-5-hydroxy-1,3-benzodioxole

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Reaction Steps

50 g of 2-(1-chloro-2,2,2-trifluoroethyl)-2-(trifluoromethyl)-5-formyl-1,3-benzodioxole were dissolved 500 ml of methylene chloride, and 53 g of 70% strength by weight m-chloroperbenzoic acid were added. The mixture was stirred under reflux for 6 hours. It was then cooled, and the precipitate which had separated out was filtered off. The filtrate was washed with 5% strength by weight aqueous sodium hydrogen sulphide solution and with saturated aqueous sodiumbicarbonate solution and concentrated on a rotary evaporator. The residue which remained was dissolved in 300 ml of diethyl ether, and 100 ml of 1N sodium hydroxide solution were added at room temperature. When the reaction had ended, the phases were separated and the organic phase was washed with saturated aqueous ammonium chloride solution, dried with magnesium sulphate and subjected to fractional distillation in vacuo. The yield was 26 g (=54% of theory), and the boiling point was 95° C. under 0.07 mbar. 19F-NMR: -68.6 and -81.6 ppm. 1H-NMR: 4.70 ppm.

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