[F:1][C:2]1[CH:17]=[C:16]([N+:18]([O-])=O)[CH:15]=[CH:14][C:3]=1[O:4][C:5]1[C:10]2=[CH:11][CH:12]=[CH:13][N:9]2[N:8]=[CH:7][N:6]=1.[Cl-].[NH4+]>O1CCCC1.CO.[Zn]>[F:1][C:2]1[CH:17]=[C:16]([NH2:18])[CH:15]=[CH:14][C:3]=1[O:4][C:5]1[C:10]2=[CH:11][CH:12]=[CH:13][N:9]2[N:8]=[CH:7][N:6]=1To a solution of 4-(2-fluoro-4-nitrophenoxy)pyrrolo[2,1-f][1,2,4]triazine (4.25 g, 15.5 mmol) in 40 mL of tetrahydrofuran and 60 mL of methanol at 0° C. was added zinc dust (3.04 g, 46.5 mmol, <10 micron) followed by ammonium chloride (2.49 g, 46.5 mmol). The mixture was stirred at room temperature overnight. Additional zinc dust (6.08 g, 93 mmol) and ammonium chloride (5.0 g, 93 mmol) were added and the reaction was allowed to stir at room temperature for 4 h. The heterogeneous mixture was filtered through a thin pad of Celite ® with methanol and the filtrate was concentrated in vacuo. Purification by flash chromatography on silica gel (SiO2, EtOAc/Hexane 1:1) gave the title compound (3.5 g, 92%) as a yellow foam. 1H NMR (CDCl3) δ 7.92 (s, 1H), 7.70 (dd, 1H, J=2.5, 1.6 Hz), 6.98 (t, 1H, J=8.5 Hz), 6.92 (dd, 1H, J=4.4, 1.4 Hz), 6.77 (m, 1H), 6.42 (m, 2H), 3.71 (br s, 2H); MS(ESI+) m/z 245.2 (M+H)+.
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