Lithium Hydroxide → [Rac]-2-ethoxy-3-[4-(5-methyl-2-phenyl-oxazol-4-ylmethoxy)-benzofuran-7-yl]-propionic acid

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Reaction Steps

Potassium carbonate (37 mg, 300 μmol, 1.4 eq.) and potassium iodide (4 mg, 30 μmol, 0.1 eq.) were added to a solution of [rac]-2-ethoxy-3-(4-hydroxy-benzofuran-7-yl)-propionic acid methyl ester (50 mg, 189 μmol) and 4-chloromethyl-5-methyl-2-phenyl-oxazole (39 mg, 189 μmol, 1 eq.) in N,N-dimethylformamide (0.5 ml). The mixture was shaken at 80° C. for 12 h, filtered off and the filtrate evaporated in vacuo to give [rac]-2-ethoxy-3-[4-(5-methyl-2-phenyl-oxazol-4-ylmethoxy)-benzofuran-7-yl]-propionic acid methyl ester. Crude [rac]-2-ethoxy-3-[4-(5-methyl-2-phenyl-oxazol-4-ylmethoxy)-benzofuran-7-yl]-propionic acid methyl ester was dissolved in a 2:1:1 mixture of THF/ethanol/water. Lithium hydroxide (40 mg, 945 μmol, 5 eq.) was added and the solution was shaken at ambient temperature for 12 h. Acidification with 25% aqueous hydrochloric acid and evaporation of the solvent in vacuo were followed by purification through a preparative HPLC column to give the title compound (28 mg, 66 μmol, 35%) as white solid.

Provenance & Evidence