2-{[6-Methoxy-1-(phenylsulfonyl)-1H-indol-5-yl]oxy}ethanamine (Intermediate 32, 2.0 g, 5.8 mmol) in DCM (100 mL) was treated with triethylamine (2.4 mL, 17 mmol) and 4-dimethylaminopyridine (0.35 g, 2.9 mmol). The solution was cooled to 0° C. and acetyl chloride (0.82 mL, 12 mmol) was added. The mixture was stirred at room temperature for 1 hour, washed with aqueous saturated NaHCO3 (20 mL) and 1 M HCl (2×20 mL). The organic phase was dried (MgSO4) and concentrated in vacuo to give the title compound (1.2 g). MS m/z 389 [M+H]+.
