Imidazole → 2-Iodomethylindoline

Beteiligte Stoffe

Reaktionsschritte

To a mixture of 2-hydroxymethylindoline (7.77 g, 52.08 mmol), imidazole (8.86g, 130.2 mmol), triphenylphosphine (34.15 g, 130.2 mmol)in toluene (500 mL) was added iodine (26.44 g, 104.16 mmol) in acetonitrile (100 mL) at 0° C. The mixture was stirred for 10 min and water was added. The organic layer was separated, washed with brine, dried over magnesium sulfate, and concentrated. The residue was triturated with diethyl ether and insoluble solids were removed by filtration. The filtrate was concentrated to give crude 2-iodomethylindoline. The crude 2-iodomethylindoline was dissolved in DMF (130 mL) and KCN (4.07 g, 62.5 mmol) was added. The mixture was heated at 80° C. for 12 h and after addition of KCN (4.07 g), the heating was further continued for 5 h. The mixture was poured into saturated aqueous sodium bicarbonate and extracted with ethyl acetate. The organic layer was washed with brine, dried over magnesium sulfate, and concentrated. The residue was purified by silica gel column chromatography with 3:1 to 2:1 hexane/ethyl acetate to give 3.04 g of 2-cyanomethylindoline (37%): 1H NMR (270 MHz, CDCl3) δ7.03 (m, 2 H), 6.77 (t, 1H, J=7 Hz), 6.54 (t, 1H, J=7 Hz), 4.42 (m, 1H), 4.13 (bs, 1H), 3.07 (m, 1H), 2.81 (dt, 1H, J=16, 4 Hz), 2.22 (m, 2H).

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