Reaction Steps
A solution of 7-phenylheptanoic acid (87 mg, 0.422 mmol), BOP (205 mg, 0.464 mmol) and DIPEA (65.38 mg, 88 μL, 0.506 mmol) in THF (2.5 mL) was stirred for 10 min. To this was added a solution of the trifluoroacetic acid salt of 4-amino-5-[1-(3-phenyl-allyl)-1H-indol-3-yl]-pent-2-enoic acid methyl ester (200 mg, 0.422 mmol) and DIPEA (163 mg, 220 μL, 1.27 mmol) in THF (2.5 mL). The mixture was stirred overnight at room temperature. The solvent was removed and the crude material subject to column chromatography (50% EtOAc/petroleum ether, Rf 0.66) to afford the title compound (133 mg, 55%). 1H NMR (CDCl3) δ 7.58 (1H, d, J=8.1 Hz), 7.36-7.09 (12H, m), 7.02-6.95 (2H, m), 6.45 (1H, d, J=15.78 Hz), 6.29 (1H, dt, J=5.63, 15.78 Hz), 5.82 (1H, d, J=15.69 Hz), 5.52 (1H, d, J=8.25 Hz), 5.01-5.09 (1H, m), 4.82 (2H, d, J=5.49 Hz), 3.66 (3H, s), 3.12 (1H, dd, J=6.35, 14.69 Hz), 3.04 (1H, dd, J=6.17, 14.69 Hz), 2.55 (2H, t, J=7.69 Hz), 2.07 (2H, t, J=7.64 Hz), 1.59-1.46 (4H, m), 1.25-1.23 (4H, m). 13C NMR (CDCl3) δ 172.5, 166.6, 148.1, 142.7, 136.4, 136.1, 132.5, 128.6, 128.4, 128.2, 127.9, 126.5, 125.6, 124.6, 120.8, 122.0, 119.5, 118.8, 109.8, 109.2, 51.6, 50.2, 48.3, 36.7, 35.8, 31.2, 29.9, 29.0, 28.9, 25.4. ISMS: 549 (M+H).
