Trifluoroacetic acid → N-(4-(((4-aminonaphthalen-1-yl)oxy)methyl)pyridin-2-yl)-6-ethylpyrazin-2-amine

TFA (1.485 mL, 19.09 mmol) was added to a solution of tert-butyl (4-((2-((6-ethylpyrazin-2-yl)amino)pyridin-4-yl)methoxy)naphthalen-1-yl)carbamate (Intermediate D (protected)) (360 mg, 0.763 mmol) in DCM (15 mL), and the reaction mixture stirred at room temperature for 4 h, then concentrated in vacuo. The residue was combined with sat. sodium hydrogencarbonate solution and stirred at room temperature for 16 h. The solid was filtered, washing with acetonitrile, and dried under vacuum to give the subtitle compound N-(4-(((4-aminonaphthalen-1-yl)oxy)methyl)pyridin-2-yl)-6-ethylpyrazin-2-amine as a beige solid (200 mg, 69%); Rt 2.14 min (Method 2); m/z 372 (M+H)+ (ES+); 1H NMR δ: 1.20 (3H, t), 2.64 (2H, q), 5.18-5.24 (4H, overlapping m), 6.59 (1H, d), 6.82 (1H, d), 7.03 (1H, d), 7.41-7.51 (2H, overlapping m), 7.98-8.01 (2H, m), 8.04 (1H, m), 8.22-8.29 (2H, overlapping m), 8.91 (1H, s), 10.04 (1H, s).