[H-].[Na+].[CH2:3]([O:5][C:6](=[O:22])[CH:7]([O:11][C:12]1[CH:20]=[CH:19][CH:18]=[C:17]2[C:13]=1[CH:14]=[C:15]([CH3:21])[NH:16]2)[CH:8]([CH3:10])[CH3:9])[CH3:4].[Br:23][CH:24](Br)[CH2:25][CH2:26][CH2:27][CH2:28][CH2:29][CH2:30][CH2:31][CH2:32][CH2:33][CH2:34][CH3:35]>CN(C=O)C.C(OCC)(=O)C>[CH2:3]([O:5][C:6](=[O:22])[CH:7]([O:11][C:12]1[CH:20]=[CH:19][CH:18]=[C:17]2[C:13]=1[CH:14]=[C:15]([CH3:21])[N:16]2[CH2:35][CH2:34][CH2:33][CH2:32][CH2:31][CH2:30][CH2:29][CH2:28][CH2:27][CH2:26][CH2:25][CH2:24][Br:23])[CH:8]([CH3:9])[CH3:10])[CH3:4]To a mixture of NaH (60% in mineral oil, 0.42 g, 10 mmole) in anhydrous DMF (20 mL), 3-methyl-2-(2-methyl-1H-indol-4-yloxy)-butyric acid ethyl ester (2) (1.88 g, 7.0 mmole) and dibromododecane (2.30 g, 7.0 mmole) were added. The mixture was stirred at room temperature for 18 h. The reaction was diluted with ethyl acetate (50 mL) and washed with water (3×30 mL). The organic layer was separated, dried over sodium sulphate and concentrated. The residue was purified by column chromatography (10:1 Hex:EtOAc) to afford intermediate (3) Yield: intermediate (3) 1.32 g, 35%, by-product (4) 1.56 g, 31%.
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