[BH4-].[Na+].[Cl:3][C:4]1[CH:5]=[C:6]([CH:25]=[CH:26][C:27]=1[Cl:28])[CH2:7][N:8]1[C:16]2[C:11](=[CH:12][C:13]([N+:17]([O-])=O)=[CH:14][CH:15]=2)[CH:10]=[C:9]1[C:20]([O:22][CH2:23][CH3:24])=[O:21].[OH-].[Na+]>C(O)C>[NH2:17][C:13]1[CH:12]=[C:11]2[C:16](=[CH:15][CH:14]=1)[N:8]([CH2:7][C:6]1[CH:25]=[CH:26][C:27]([Cl:28])=[C:4]([Cl:3])[CH:5]=1)[C:9]([C:20]([O:22][CH2:23][CH3:24])=[O:21])=[CH:10]2Sodium borohydride (1.19 g) in ethanol was added dropwise to ethyl N-(3,4-dichlorobenzyl)-5-nitroindole-2-carboxylate (12.4 g) and stannous chloride dihydrate (35.6 g) in ethanol at 60° C. and reaction stirred for 5 hours. The mixture was then cooled, made basic with 2N sodium hydroxide and extracted with ethyl acetate. Combined organic extracts were dried (MgSO4) and concentrated to give an oil which crystallised upon trituration with i-hexane. Filtration yielded the desired end product as a pale brown solid (1.18 g, 10%); NMR δ (CDCl3) 1.32 (t, 3H), 4.26 (q, 2H), 6.69 (s, 2H), 6.78-7.35 (m, 7H); M/z (−) 363 (M+), 274, 267, 265, 151, 121, 102.
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