To a solution of 5-(3-(6-(isopropylamino)pyrazin-2-yl)-1-tosyl-1H-indol-5-yl)-1,2,4-thiadiazol-3-amine (0.5 g, 0.99 mmol) in 1,4-dioxane (5 mL) was added 10% aq NaOH (2.5 mL) and the reaction was heated at 100° C. for 2 hr. The mixture was cooled to RT and was treated with ice cold water to give off white precipitate. The precipitate was filtered and washed with ice cold water and further purified by preparative HPLC (eluent: 10-70% MeCN:MeOH (1:1) in water with 0.01% TFA) to give 5-(3-(6-(isopropylamino)pyrazin-2-yl)-1-tosyl-1H-indol-5-yl)-N-(4-methoxybenzyl)-1,2,4-thiadiazol-3-amine (70 mg, 20%). MS (ESI, pos. ion) m/z: 352.1 (M+1); 1H-NMR (400 MHz, DMSO-d6): δ 11.96 (s, 1H), 9.05 (d, J=1.2 Hz, 1H), 8.27 (m, 2H), 7.78 (d, J=8.4 Hz, 1H), 7.67 (m, 2H), 7.59 (d, J=8.4 Hz, 1H), 7.20 (m, 1H), 4.61 (m, 1H), 1.32 (d, J=6.4 Hz, 6H).
