Chlorosulfonic acid → 173669-61-9

Participants

Reaction Conditions

Reaction Steps

ClSO3H (400 g, 3.45 mol) was cooled to 0° C. and 1-methylindoline (35 g, 263.16 mmol) was added dropwise with stirring, maintaining the temperature at 0° C. The resulting solution was then warmed to room temperature and stirred for 20 hours. The reaction mixture was added carefully then dropwise to 3 L of iced water and the resulting solution was extracted using dichloromethane (3×400 mL). The organic layers were combined, dried (Na2SO4) and concentrated. The resulting residue was purified by column chromatography using a 1:30 ethyl acetate/petroleum ether solvent system. The collected fractions were combined and concentrated to give 4.2 g (7%) of 1-methylindoline-6-sulfonyl chloride as a brown solid. 1H NMR (CDCl3) δ 7.34 (d, 1H), 7.20 (d, 1H), 6.95 (s, 1H), 3.52 (t, 2H), 3.08 (t, 2H), 2.86 (s, 3H).

Provenance & Evidence