To a solution of (3S,3aR)-2-(3-chloro-4-cyanophenyl)-3-cyclopentyl-3,3a,4,5-tetrahydro-2H-benzo[g]indazole-7-carboxylic acid, Example 15 (100 mg, 0.24 mmol) in N,N-dimethylformamide (3 mL) was added 1-hydroxybenzotriazole (48 mg, 0.36 mmol), triethylamine (0.07 mL, 0.48 mmol) and O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium tetrafluoroborate (115 mg, 0.36 mmol). The solution was stirred for fifteen minutes followed by addition of 2-aminoethanesulfonamide (44 mg, 0.36 mmol). The solution was stirred for twenty hours at ambient temperature. The reaction was partitioned between ethyl acetate and water. The organic layer was washed with water and brine and dried over magnesium sulfate. Chromatography (reverse phase, acetonitrile/water) provided (3S,3aR)-2-(3-chloro-4-cyanophenyl)-3-cyclopentyl-N-(2-sulfamoylethyl)-3,3a,4,5-tetrahydro-2H-benzo[g]indazole-7-carboxamide (yellow solid, 10 mg, 8% yield). LC/MS on 4.6×50 mm C-18 column, tR=5.80 minutes (10 to 90% acetonitrile/water over 6 minutes at 2 mL/minute with detection 254 nm, at 50° C.); ES-MS m/z 526 (M+H).
