A solution of 3-methoxy-4-[1-methyl-5-(2-methyl-4,4,4-trifluorobutylcarbamoyl)indol-3-ylmethyl]benzoic acid (250 mg), 4-dimethylaminopyridine (69.8 mg), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (127 mg) and 2-methylbenzenesulfonamide (95.4 mg) in methylene chloride (5 mL) was stirred under a nitrogen atmosphere for 24 hours. The mixture was diluted with methylene chloride, washed (10% (w/v) hydrochloric acid, water), and evaporated. The resulting rose-colored foam was dissolved in methylene chloride (5 mL), filtered through a 0.45 micron membrane filter, and precipitated by addition to hexane (50 mL). The solid was collected by filtration to give the title compound (189.2 mg, 57%) as a pale pink powder; mp 147°-149 ° C.
