5-(4-Methylpiperazin-1-yl)-indole (215 mg, 1 mmol), benzenesulfonylchloride (265 mg, 1.5 mmol) and Aliquat 336 (10 mg) were dissolved in DCM (10 mL). Aqueous NaOH (20%, 2 mL) was added and the mixture was stirred vigorously for 6 h. The organic layer was separated, dried and concentrated to give the crude as an oil that was purified on a silica column using DCM and MeOH as eluent. The pure fractions were concentrated to give an oil (260 mg, 0.66 mmol) 1H NMR (CDCl3) δ 2.35 (3 H, s), 2.59 (4 H, t, J=5), 3.18 (4 H, t, J=5), 6.57 (1 H, d, J=4), 6.98–7.03 (2 H, m), 7.38–7.54 (4 H, m), 7.82–7.90 (3 H, m); MS (posES-FIA) 355.1345 M+; Purity (HPLC chromsil C18) >98%.
