Trifluoroacetic acid → 1-(2-(1,2,3,6-tetrahydropyridin-4-yl)-4-(trifluoromethyl)phenyl)-N-(thiazol-2-yl)isoquinoline-6-sulfonamide

Tert-butyl 4-(2-(6-(N-(2,4-dimethoxybenzyl)-N-(thiazol-2-yl)sulfamoyl)isoquinolin-1-yl)-5-(trifluoromethyl)phenyl)-5,6-dihydropyridine-1(2H)-carboxylate (0.073 g, 0.095 mmol) was dissolved in 1 mL of DCM and TFA (0.073 ml, 0.948 mmol) was added. The reaction was stirred overnight at room temperature. The solution was concentrated and concentrated from DCM two more times. The resulting yellow solid was triturated with diethyl ether and stirred for 15 minutes. The solution was filtered and the solids were washed with diethyl ether. The material was dissolved in methanol and loaded onto an SCX ion exchange column (pre-wetted with methanol) (Biotage AB, Uppsala, SE). The column was washed several times with methanol, then the product was liberated with 2.0 M ammonia/methanol solution. The filtrate was concentrated to afford 1-(2-(1,2,3,6-tetrahydropyridin-4-yl)-4-(trifluoromethyl)phenyl)-N-(thiazol-2-yl)isoquinoline-6-sulfonamide as a light yellow solid. 1H NMR (400 MHz, DMSO-d6) δ=8.60 (d, J=5.7 Hz, 1H), 8.44 (d, J=1.5 Hz, 1H), 8.05 (d, J=5.4 Hz, 1H), 7.93-7.79 (m, 2H), 7.72 (s, 1H), 7.61 (dd, J=8.4, 16.3 Hz, 2H), 6.96 (d, J=3.9 Hz, 1H), 6.52 (d, J=3.9 Hz, 1H), 5.49 (br. s., 1H), 3.24 (br. s., 2H), 2.72 (t, J=5.8 Hz, 2H), 2.04 (br. s., 2H). m/z (ESI) 517.2 (M+H)+.