Diisopropylethylamine → 3-(2,6-Dichloro-phenyl)-2-[4-(2,6-difluoro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-propionic acid methyl ester

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Reaction Conditions

Reaction Steps

In a flask was placed 2-amino-3-(2,6-dichloro-phenyl)-propionic acid methyl ester hydrochloride salt (313 mg, 1.10 mmol), acetonitrile (5 mL) and N,N-diisopropylethylamine (200 μL, 1.23 mmol). This mixture was stirred at 60° C. for 1 h and then cooled to 25° C. The mixture was then treated with N,N-diisopropylethylamine (200 μL, 1.23 mmol) and heated at 80° C. and a solution of 4-bromo-3-(2,6-difluoro-phenoxy)-but-2-enoic acid ethyl ester (prepared as in Example 36, 321 mg, 1.00 mmol) in acetonitrile (1 mL) was added slowly. The mixture was heated at 100° C. for 16 h and then placed in a sealed microwave tube and heated at 140° C. for 1 h in the microwave. The mixture was then concentrated in vacuo with silica gel (2 g). Purification by Biotage flash chromatography (40S column, 10% ethyl acetate/hexanes to 100% ethyl acetate) afforded 3-(2,6-dichloro-phenyl)-2-[4-(2,6-difluoro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-propionic acid methyl ester (58 mg, 12%) as a gold oil: HR-ES-MS m/z calculated for C20H15NO4Cl2F2 [M+H]+ 442.0419, observed 442.0420.

Provenance & Evidence