Chlorosulfonic acid → 5-Chlorosulphonyl-2-(2,2,2-trifluoroethyl)-2-trifluoromethyl-1,3-benzodioxole

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Reaction Steps

136 g of 2-(2,2,2-trifluoroethyl)-2-trifluoromethyl-1,3-benzodioxole were dissolved in 125 ml of chloroform. 175 g of chlorosulphonic acid were added dropwise at 0° C., with stirring, and the reaction mixture was subsequently stirred at room temperature until the evolution of gas had ended. It was then poured into 750 g of ice-water, the phases were separated and the aqueous phase was extracted with chloroform. The combined organic phases were washed with ice-water and sodium hydrogencarbonate solution and dried over magnesium sulphate and the readily volatile components were removed on a rotary evaporator to give 133 g of product (=72% of theory). The melting point was 55° to 57° C. 19F NMR: -60.8 and -86.5 ppm. 1H NMR: 3.13 ppm.

Provenance & Evidence