C([O:3][C:4]([C:6]1[CH:7]=[C:8]2[C:12](=[C:13]([N+:15]([O-:17])=[O:16])[CH:14]=1)[NH:11][C:10]([C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1)=[CH:9]2)=O)C.[Li+].[BH4-].O>CO>[OH:3][CH2:4][C:6]1[CH:7]=[C:8]2[C:12](=[C:13]([N+:15]([O-:17])=[O:16])[CH:14]=1)[NH:11][C:10]([C:18]1[CH:19]=[CH:20][CH:21]=[CH:22][CH:23]=1)=[CH:9]22-Phenyl-7-nitro-1H-indole-5-carboxylic acid ethyl ester (10 g, 29 mmol) prepared in Step A of Example 28 was dissolved in methanol (100 mL), and LiBH4 (1M THF solution, 4 mL) was added thereto at 0° C. After warming to room temperature, the mixture was stirred for 3 h. A small amount of water was added to quench the reaction. Methanol was removed under reduced pressure. 1N HCl was added to the residue, which was then extracted with EtOAc, dried, and used in the next reaction without further purification.
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