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., while stirring, and the mixture was subsequently stirred at room temperature until the evolution of gas had ended. It was then poured onto 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 bicarbonate solution, dried with magnesium sulphate and freed from readily volatile constituents on a rotary evaporator. 133 g of product were obtained (=72% of theory), and the melting point was 55° to 57° C. 19F-NMR: -60.8 and -86.5 ppm. 1H-NMR: 3.13 ppm.

Provenance & Evidence