Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl ester → 5-[(5-fluoro-3-iodo-1H-indole-2-carbonyl)-amino]-pent-2-enoic acid ethyl ester

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Reaction Steps

To a solution of 5-fluoro-3-iodo-1H-indole-2-carboxylic acid (3-oxo-propyl)-amide, prepared as in reference 13, (5.86 g, 16.3 mmol) in THF (200 mL) is added (carbethoxymethylene) triphenylphosphorane (18 g, 51.7 mmol) at 0° C. The reaction is stirred at room temperature overnight. It is washed with saturated NH4Cl (200 mL) and extracted with Et2O (200 mL×2). The combined organic layers are washed with brine and dried. It is concentrated and purified by silica gel column chromatography and eluted with EtOAc-Hexanes to give 5-[(5-fluoro-3-iodo-1H-indole-2-carbonyl)-amino]-pent-2-enoic acid ethyl ester as the trans isomer; 1H NMR (DMSO-d6) δ 1.25 (t, 3H, J=6.8 Hz), 2.52 (t, 2H, J=6.8 Hz), 3.48 (q, 2H, J=5.6 Hz), 4.10 (q, 2H, 6.8 Hz), 5.96 (d, 1H, J=15.6 Hz), 6.96 (dt, 1H, J1=5.8 Hz, J2=15.6 Hz), 7.06-7.18 (m, 2H), 7.46 (dd, 1H, J1=4.0 Hz, J2=8.8 Hz), 8.11 (t, 1H, J=6.4 Hz), 12.10 (s, 1H); m/z [M++1] 431.0.

Provenance & Evidence