C[Si]([N-][Si](C)(C)C)(C)C.[K+].[C:11]1(C)C=CC=CC=1.[N+:18]([C:21]1[CH:29]=[C:28]2[C:24]([CH2:25][CH2:26][NH:27]2)=[CH:23][CH:22]=1)([O-:20])=[O:19].IC>O1CCCC1.CO>[CH3:11][N:27]1[C:28]2[C:24](=[CH:23][CH:22]=[C:21]([N+:18]([O-:20])=[O:19])[CH:29]=2)[CH2:25][CH2:26]1
Potassium bis(trimethylsilyl)amide (67 ml of a 0.5M toluene solution) was added slowly to a stirred solution of 6-nitroindoline (5.0 g) in anhydrous tetrahydrofuran (200 ml) at -78° C. under a nitrogen atmosphere. Iodomethane (2.09 ml) was added then the reaction mixture was allowed to warm to room temperature then stirred overnight. Methanol (5 ml) was added then the solution was evaporated to dryness. The residue was dissolved in diethyl ether (300 ml), washed with water, saturated brine then dried (magnesium sulphate) and evaporated to dryness. The crude product was purified by column chromatography on silica using 10% ethyl acetate/petroleum ether (60-80)→30% ethyl acetate/petroleum ether (60-80) and the product crystallised from diethyl ether/petroleum ether (60-80) to afford 0.9 g.
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