[NH2:1][CH2:2][CH2:3][C:4]1[C:12]2[C:7](=[CH:8][CH:9]=[C:10]([OH:13])[CH:11]=2)[NH:6][CH:5]=1.N1C=CN=C1.[CH:19]([Si:22](Cl)([CH:26]([CH3:28])[CH3:27])[CH:23]([CH3:25])[CH3:24])([CH3:21])[CH3:20]>CN(C)C=O.C(OCC)(=O)C>[CH:19]([Si:22]([CH:26]([CH3:28])[CH3:27])([CH:23]([CH3:25])[CH3:24])[O:13][C:10]1[CH:11]=[C:12]2[C:7](=[CH:8][CH:9]=1)[NH:6][CH:5]=[C:4]2[CH2:3][CH2:2][NH2:1])([CH3:21])[CH3:20]A solution of 3-(2-amino-ethyl)-1H-indol-5-ol (3.0 g), imidazole (9.6 g), and triisopropylsilyl chloride (4.5 mL) was stirred in 20 mL N,N-dimethylformamide for 6 h. The solution was diluted with 100 mL of ethyl acetate and washed with 100 mL of sodium carbonate and 100 mL of saturated sodium chloride (3 times). The organic phase was dried over sodium sulfate and the solvent was evaporated. Silica gel chromatography (2% methyl alcohol in dichloromethane) gave 2-(5-triisopropylsilanyloxy-1H-indol-3-yl)-ethylamine (2.6 g). This compound was cyclized with formaldehyde by Procedure OO to afford 6-triisopropylsilanyloxy-2,3,4,9-tetrahydro-1H-β-carboline, which was protected with tert-butoxycarbonyl group by Procedure CC to give 6-triisopropylsilanyloxy-1,3,4,9-tetrahydro-β-carboline-2-carboxylic acid tert-butyl ester.
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