CN([CH2:4][C:5]1[C:9]2[CH:10]=[CH:11][CH:12]=[C:13]([O:14][CH2:15][C:16]3[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=3)[C:8]=2[NH:7][CH:6]=1)C.[OH-].[Na+].[N+:24]([CH:27]([CH3:29])[CH3:28])([O-:26])=[O:25]>CCOCC>[CH3:28][C:27]([N+:24]([O-:26])=[O:25])([CH3:29])[CH2:4][C:5]1[C:9]2[C:8](=[C:13]([O:14][CH2:15][C:16]3[CH:17]=[CH:18][CH:19]=[CH:20][CH:21]=3)[CH:12]=[CH:11][CH:10]=2)[NH:7][CH:6]=1A mixture of 7-benzyloxy gramine (1.99 g, 7.10 mmol), solid NaOH (298 mg, 7.22 mmol) and 2-nitropropane (4.5 mL, 50 mmol) is heated to reflux. After 10 minutes at reflux, a thick slurry developed which is difficult to stir. Gas evolution is observed, and an additional 1 mL of 2-nitropropane is added to loosen the mixture. After 29 hours, the mixture is allowed to cool to ambient temperature. Ether (30 mL) is added and the mixture is filtered. The filtrate is treated with 10% acetic acid (6 mL), the layers are separated and the organic layer is rinsed with water (2×25 mL). The organic layer is dried (Na2SO4) and concentrated to give 2.12 g of 3-(2-methyl-2-nitropropyl)-7-(benzyloxy)indole (92%). MS (ES+) m/z 325.
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