[H-].[H-].[H-].[H-].[Li+].[Al+3].C(OC(C1NC2C(C=1)=C([N+]([O-])=O)C=CC=2)=O)C.C(O[C:27]([C:29]1[NH:30][C:31]2[C:36]([CH:37]=1)=[CH:35][CH:34]=[C:33]([N+:38]([O-])=O)[CH:32]=2)=O)C.[OH-].[Na+]>C1COCC1.O>[CH3:27][C:29]1[NH:30][C:31]2[C:36]([CH:37]=1)=[CH:35][CH:34]=[C:33]([NH2:38])[CH:32]=2
To a suspension of LiAlH4 (7.8 g, 0.21 mol) in THF (300 mL) was added dropwise a mixture of 4-nitro-1H-indole-2-carboxylic acid ethyl ester and 6-nitro-1H-indole-2-carboxylic acid ethyl ester (B-4-b) (6 g, 25.7 mmol) in THF (50 mL) at 0° C. under N2. The mixture was heated at reflux overnight and then cooled to 0° C. H2O (7.8 mL) and 10% NaOH (7.8 mL) were added to the mixture at 0° C. The insoluble solid was removed via filtration. The filtrate was dried over Na2SO4, filtered and concentrated under reduced pressure. The crude residue was purified by column chromatography to afford 2-methyl-1H-indol-6-ylamine (B-4) (0.3 g, 8%). 1H NMR (CDCl3) δ 7.57 (br s, 1 H), 7.27 (d,J=8.8 Hz, 1 H), 6.62 (s, 1 H), 6.51-6.53 (m, 1 H), 6.07 (s, 1 H), 3.59-3.25 (br s, 2 H), 2.37 (s, 3H); ESI-MS 147.2 m/z (MH+).
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