[CH3:1][N:2]1[C:10]2[C:5](=[CH:6][C:7]([O:11][CH2:12][C:13]3[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=3)=[CH:8][CH:9]=2)[C:4]([O:19][CH:20]([CH3:22])[CH3:21])=[C:3]1[C:23]([O:25]C(C)(C)C)=[O:24].[OH-].[Na+].O>COCCO>[CH3:1][N:2]1[C:10]2[C:5](=[CH:6][C:7]([O:11][CH2:12][C:13]3[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=3)=[CH:8][CH:9]=2)[C:4]([O:19][CH:20]([CH3:22])[CH3:21])=[C:3]1[C:23]([OH:25])=[O:24]A suspension of 1,1-dimethylethyl 1-methyl-3(1-methylethoxy)-5-(phenylmethoxy)-1H-indole-2-carboxylate (5.6 g, 14 mmol) in 80 mL of 2-methoxyethanol is treated with a solution of 50% aqueous sodium hydroxide (5.0 g, 63 mmol) followed by the addition of 15 mL of water. The mixture is stirred at reflux for 3 hours, then cooled and added to 700 mL of water. The mixture is heated on a hot plate until nearly one phase and filtered hot. The warm filtrate is immediately treated with 50 mL of 4.0N HCl. After cooling to room temperature, followed by 1 hour in an ice bath, the precipitated solid is filtered and washed with 25% methanol in water to give 4.2 g (88%) of product suitable for further synthesis. A sample recrystallized from ethyl acetate-hexane has mp 136° C.-dec.
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