Tetrahydrofuran → 4-tert-Butoxycarbonylamino-5-(1-trityl-1H-imidazol-4-yl)-pent-2-enoic acid ethyl ester

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Reaction Steps

Ethyl (triphenylphosphoranylidene)acetate (1.52 g, 4.37 mmol) and [1-formyl-2-(1-trityl-1H-imidazol-4-yl)-ethyl]-carbamic acid tert-butyl ester (2.1 g, 4.38 mmol) in THF (35 mL) were stirred overnight under argon. The solvent was removed, Et2O added and the solution filtered. The filtrate was concentrated and the residue subject to column chromatography (silica gel, 25% EA/PE, Rf 0.65 50% EA/PE) to afford the title compound (1.6 g, 67%). ESMS 552 (M+H+) Mpt . 1H NMR (300 MHz, CDCl3) δ 1.28 (3H, t, J=7.5), 1.34 (9H, s), 3.01-3.05 (2H, m), 4.19 (2H, q, J=7.05), 4.47-4.57 (1H, m), 6.01 (1H, dd, J=1.5, 15.9), 6.46 (1H, d, J=9.3), 6.86 (1H, s), 6.89 (1H, dd, J=5.1, 15.9), 7.07-7.11 (5H, m), 7.21-7.3 (2H, m), 7.4-7.44 (8H, m), 8.11 (1H, s). 13C NMR (300 MHz, CDCl3) δ 166.14, 155.87, 139.86, 135.20, 132.21, 129.49, 129.70, 129.01, 128.18, 122.33, 121.19, 79.74, 78.78, 60.76, 52.09, 30.12, 28.35, 14.32.

Provenance & Evidence