Benzenesulfonyl chloride → benzenesulphonic acid 2-(1-benzenesulphonyl-5-methoxy-1H-indol-3-yl)ethyl ester

Participants

Reaction Steps

To a stirred two-phase mixture of 5-methoxytryptophol (0.150 g, 0.785 mmol) and tetrabutylammonium hydrogen sulphate (27 mg, 0.0785 mmol) in 50% aqueous NaOH (3 ml) and dichloromethane (30 ml) was added benzenesulphonyl chloride (0.25 ml, 1.96 mmol) dropwise over 5 min. The mixture was stirred for 20 min, more benzenesulphonyl chloride 0.10 ml, 0.784 mmol) was added dropwise, and the mixture was stirred for a further hour. The organic layer was washed with brine, dried (Na2SO4) and evaporated in vacuo. The residue was purified by flash chromatography (silica gel, 50-100% EtOAc/hexane) to afford 0.095 g (37%) of 2-(1-benzenesulphonyl-5-methoxy-1H-indol-3-yl)ethanol and 0.191 g (52%) of the title compound; δH (360 MHz, d6-DMSO) 2.98 (2H, t, J 6.1 Hz), 3.71 (3H, s), 4.30 (2H, t, J=6.2 Hz), 6.92 (1H, dd, J=8.9, 2.5 Hz), 6.95 (1H, d, J=2.2 Hz), 7.47 (2H, t, J=7.8 Hz), 7.53-7.59 (3H, m), 7.63-7.67 (4H, m), 7.77 (1H, d, J=8.9 Hz), 7.89 (2H, m); m/z (ES+) 510 (M+K)+, 494 (M+Na)+, 489 (M+NH4)+, 472 (M+H)+.

Provenance & Evidence