The product from Example 3, 5-(5,6-difluoro-1H-indol-2-yl)-2-methoxy-phenylamine (0.548 g, 2.0 mmol), was mixed with 3-nitrobenzenesulfonyl chloride (0.466 g, 2.0 mmol) and pyridine (9 mL) was added, and the reaction mixture was heated briefly to 50° C. and then allowed to stand overnight at room temperature. Water (15 mL) was added and the mixture allowed to stand 1.5 hours at room temperature. The mixture was partitioned between water (200 mL) and ethyl acetate (200 mL), and the organic layer was washed with 1N HCl (100 mL), water (100 mL), and brine (100 mL), dried (magnesium sulfate), filtered, and concentrated to a yellow solid. The solid was triturated with hexanes/ethyl acetate, 1/1, dried in vacuo, taken up in tetrahydrofuran, concentrated to dryness, triturated with hexanes/ethyl acetate, 4/1, v/v and was collected by filtration (0.488 g), mp 228-230° C.
