Trifluoroacetic acid → [3-Chloro-4-(pyridin-2-ylmethoxy)-phenyl]-(5,6,7,8-tetrahydro-9-thia-1,3,7-triaza-fluoren-4-yl)amine

To a 4-[3-Chloro-4-(pyridin-2-ylmethoxy)-phenylamino]-5,8-dihydro-6H-9-thia-1,3,7-triaza-fluorene-7-carboxylic acid tert-butyl ester (3.6 g, 6.87 mmol) in DCM (45 mL) solution was added TFA (5.2 mL, 68.7 mmol, 10 equiv). The reaction mixture was stirred at rt for 8 h. The solution mixture was concentrated in vacuo. To the residue was added sat. NaHCO3 solution and stirred at rt for 1.5 h. The mixture was then filtered and washed with water. The damp solid was placed in a vacuum oven and dried for overnight to yield a yellow solid (2.0 g, 67%). 1H NMR (DMSO-d6) δ 9.41 (broad s, 2H), 8.71 (d, J=5.0 Hz, 1H), 8.40 (s, 1H), 8.11 (t, 1H), 7.75 (m, 2H), 7.57 (m, 1H), 7.53 (dd, J=2.7, 9.0 Hz, 1H), 7.25 (d, J=9.4 Hz, 1H), 5.35 (s, 2H), 4.48 (m, 2H), 3.49 (m, 2H), 3.41 (m, 2H); LCMS RT=2.11 min, [M+Na]+=446.1.