3-Chlorobenzoic Acid → 3-(4-Methylbenzene-1-sulfonyl)-6-oxa-3-azabicyclo[3.1.0]hexane

Participants

Reaction Conditions

Reaction Steps

334.5 g (1.5 mol) of 1-(toluene-4-sulphonyl)-pyrroline are dissolved in 1.5 l of dichloromethane at room temperature and treated in the course of 15 minutes with a suspension of 408 g (about 1.65-1.77 mol) of 70-75% strength m-chloroperbenzoic acid in 900 ml of dichloromethane (cools during preparation). The mixture is heated under reflux for 16 hours (test for peroxide with KI/starch paper still indicates peroxide content), the suspension is cooled to 5° C., and the precipitated m-chlorobenzoic acid is, filtered off with suction and washed with 300 ml of dichloromethane (peroxide test with precipitate: negative; precipitate discarded). The filtrate is washed twice with 300 ml of 10% strength sodium sulphite solution in each case to destroy excess peroxide (test for peroxide is now negative), extracted with 300 ml of saturated sodium bicarbonate solution, washed with water, dried using sodium sulphate and concentrated to about a quarter of the volume. Test for peroxide again: negative. The mixture is concentrated and the solid residue is stirred with 400 ml of isopropanol with ice-cooling, and the precipitate is filtered off with suction and dried in vacuo at 70° C.

Provenance & Evidence