Reaction Steps
A solution of 7-phenylheptanoic acid (92 mg, 0.447 mmol), BOP (217 mg, 0.491 mmol) and DIPEA (69 mg, 93 μL, 0.535 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-benzyl-1H-indol-3-yl)-pent-2-enoic acid methyl ester (200 mg, 0.446 mmol) and DIPEA (173 mg, 233 μL, 1.34 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 (197 mg, 85%). 1H NMR (CDCl3) δ 7.59 (1H, d, J=7.26 Hz), 6.94-7.28 (15H, m), 5.81 (1H, d, J=15.81 Hz), 5.48 (1H, d, J=8.34 Hz), 3.59 (2H, s), 5.05 (1H, m), 3.12 (1H, dd, J=6.42, 14.49 Hz), 3.04 (1H, dd, J=5.85, 14.49 Hz), 2.57 (2H, t, J=7.64 Hz), 2.07 (2H, t, J=7.67 Hz), 1.9-1.2 (8H, m). 13C NMR (CDCl3) δ 172.5, 166.5, 148.1, 142.6, 137.3, 136.6, 128.7, 128.4, 128.3, 128.2, 127.6, 126.9, 126.7, 125.6, 122.1, 120.8, 119.6, 118.8, 109.9, 109.4. 51.6, 49.9, 50.2, 36.7, 35.8, 31.2, 29.9, 29.0, 28.9, 25.4. ISMS: 523 (M+H).
