Chlorosulfonic acid → HCID 46739849, compound

Participants

Reaction Steps

1,3-Dihydro-indol-2-one 64a (13.3 g, 100 mmol) was added slowly with chlorosulfuric acid (26.6 ml, 400 mmol) in an ice-water bath. Upon completion of the addition, the reaction mixture was stirred for 1 hour in an ice-water bath, for another 1 hour at room temperature, and heated to 68° C. for 1 hour. The reaction mixture was cooled down to room temperature, added slowly with water (400 ml), stirred and yellow precipitates were formed. After standing for 1 hour at room temperature, the filter cake was washed with water (20 ml×4) and dried to obtain the title compound 5-chlorosulfonyl-indol-2-one 64b (15.0 g, yield 65%) as a yellow solid.

Provenance & Evidence