[N+:1]([C:4]1[C:12]2[C:7](=[CH:8][C:9]([Cl:14])=[CH:10][C:11]=2[Cl:13])[NH:6][C:5]=1[C:15]([O:17][CH2:18][CH3:19])=[O:16])([O-])=O.[Sn](Cl)Cl.C(=O)([O-])[O-].[K+].[K+].C(=O)=O>C(O)C.O.C(OCC)(=O)C>[NH2:1][C:4]1[C:12]2[C:7](=[CH:8][C:9]([Cl:14])=[CH:10][C:11]=2[Cl:13])[NH:6][C:5]=1[C:15]([O:17][CH2:18][CH3:19])=[O:16]Dissolve 3-nitro-2-carbethoxy-4,6-dichloroindole (38.1 g) in ethanol (1 L) and add tin (II) chloride dehydrate (163 g). Warm to between 65° and 65° C. for 4 to 5 hours. Cool to room temperature and pour into a mixture of ethyl acetate (3 L) and water (2 L). Add solid potassium carbonate and stir occasionally until the carbon dioxide evolution ceases. Filter throught Celite and separate the organic phase of the filtrate. Dry (MgSO4) and evaporate the solvent in vacuo to give the title compound as an off-yellow solid (33.5 g, 97.6%).
Loading…
