4-Formylbenzoic acid → 3-[2-(Benzofuran-2-ylmethoxycarbonylamino)-2-(1-phenyl-ethylcarbamoyl)-propyl]-indole-1-carboxylic acid 4-formylbenzoyloxymethyl ester

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Reaction Steps

Compound 7 (1.7 g, 2.5 mmol) and the silver salt of 4-carboxybenzaldehyde (1.29 g, 5.0 mmol) in dry toluene (50 mL) was refluxed for 30 minutes to give a yellow suspension. The solid was removed by filtration through celite, and the solid cake was washed with toluene. The filtrate was concentrated to give a syrup, which was purified by silica gel column eluting with CHCl3 to give compound 19 as a white foam (1.41 g, 80%).

Provenance & Evidence