To a solution of benzo[b]thiophene-2-sulfonic acid (2-aminophenyl)-amide (1 mmol, prepared as in Example 1) in DCM (2 mL) and pyridine (2 mL), 2-methoxy-5-methylbenzenesulfonyl chloride (1.1 mmol) was added at RT and the reaction mixture was then allowed to stir at RT overnight. The reaction mixture was then diluted with DCM (10 mL). The organic phase was washed with 10% aqueous HCl (10 mL), water (10 mL) and brine (10 mL). The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum. The residue obtained was purified by flash column chromatography eluting with DCM/EtOAc to obtain 390 mg of benzo[b]thiophene-2-sulfonic acid [2-(2-methoxy-5-methylbenzenesulfonylamino)phenyl]-amide. LC: Tr 1.25 min; MS: 489.1 (M+1)+.
