Water → 2-(pyridin-2-yl)-1H-indol-5-amine

Reaction equation

[N+:1]([C:4]1[CH:5]=[C:6]2[C:10](=[CH:11][CH:12]=1)[NH:9][C:8]([C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][N:14]=1)=[CH:7]2)([O-])=O.Cl[Sn]Cl.O>CCO>[N:14]1[CH:15]=[CH:16][CH:17]=[CH:18][C:13]=1[C:8]1[NH:9][C:10]2[C:6]([CH:7]=1)=[CH:5][C:4]([NH2:1])=[CH:12][CH:11]=2

Participants

Procedure

To a solution of 5-nitro-2-(pyridin-2-yl)-1H-indole (700 mg, 2.9 mmol) in EtOH (20 mL) was added SnCl2 (2.6 g, 12 mmol). The mixture was heated at reflux for 10 h. Water was added and the mixture was extracted with EtOAc (50 mL×3). The combined organic layers were washed with brine, dried over anhydrous Na2SO4 and concentrated in vacuum. The residue was purified by chromatography on silica gel (5-10% ethyl acetate/petroleum ether) to afford 2-(pyridin-2-yl)-1H-indol-5-amine (120 mg, 20%). 1H NMR (400 MHz, CDCl3) δ 9.33 (brs, 1H), 8.55 (dd, J=1.2, 3.6 Hz, 1H), 7.76-7.67 (m, 2H), 7.23 (d, J=6.4 Hz, 1H), 7.16-7.12 (m, 1H), 6.94 (d, J=2.0 Hz, 1H), 6.84 (d, J=2.4 Hz, 1H), 6.71-6.69 (dd, J=2.0, 8.4 Hz, 1H).