1-ethylsulfonylpyrrolidine

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Under an N2 atmosphere, 68.8 ml (0.11 mol) of a 1.6N solution of n-butyllithium in hexane are added dropwise at -78° C. to 16.3 (0.1 mol) of 1-ethylsulfonylpyrrolidine in 150 ml of absolute tetrahydrofuran. After 6 hours at -78° C., 26.0 g (0.4 mol) of sulfur dioxide are passed in at the same temperature, the mixture is subsequently allowed to come to room temperature, and stirring is continued for 14 hours. Evaporation of the reaction solution gives a crude sulfinate which is dissolved in 300 ml of water without purification. 18.0 g (0.22 mol) of sodium acetate in 20 ml of water and 12.4 g (0.11 mol) of hydroxylamine-O-sulfonic acid in 10 ml of water are added in succession, and the mixture is stirred for 7 hours at room temperature. The water phase is extracted using ethyl acetate, and the organic phase is dried and evaporated. For purification, the crude product obtained in this manner is taken up in 200 ml of 2N sodium hydroxide solution, the water phase is washed 3 times using 100 ml portions of diethyl ether, and the water phase is acidified with hydrochloric acid to pH 2 and extracted using ethyl acetate. After the organic phase has been dried and evaporated, 12.8 g (53% of theory) of 1-pyrrolidinosulfonylethanesulfonamide of melting point 78°-80° C. remain. to come to room temperature is continued for 14 hours Evaporation of the reaction solution gives a crude sulfinate which the mixture is stirred for 7 hours at room temperature The water phase is extracted the organic phase is dried evaporated For purification