Chlorosulfonic acid → 1-acetyl-5-bromo-2,3-dihydro-1H-indole-6-sulfonyl chloride

Participants

Reaction Conditions

Reaction Steps

Under N2 atmosphere, 25.00 mL chlorosulfonic acid was cooled in an ice bath, and under stirring 5.00 g 1-acetyl-5-bromoindoline was added portionwise. Stirring was continued for 20 min. after which the ice bath was removed and the mixture was heated to 70° C. After cooling to room temperature, the mixture was cautiously poured into ice water and extracted twice with DCM. The combined organic layers were dried over MgSO4 and evaporated to dryness to give 6.57 g (93%) of a beige solid. 1H NMR (400 MHz, DMSO-d6) δ 2.16 (s, 3H), 3.15 (t, J=8.58 Hz, 2H), 4.11 (t, J=8.58 Hz, 2H), 7.37 (s, 1H), 8.66 (s, 1H).

Provenance & Evidence