3-(2-Chloro-phenoxy)-4-(3,3-difluoro-1-methoxycarbonyl-propylamino)-but-2-enoic acid ethyl ester → 2-[4-(2-Chloro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-4,4-difluoro-butyric acid methyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 3-(2-chloro-phenoxy)-4-(3,3-difluoro-1-methoxycarbonyl-propylamino)-but-2-enoic acid ethyl ester (1.19 g, 3.04 mmol) in acetonitrile (4 mL) was placed in a sealed microwave reaction tube and heated in a microwave reactor at 180° C. for 3 h. The mixture was then cooled to room temperature and concentrated in vacuo with silica gel (3 g). Purification by Biotage flash chromatography (Aspire 40 g column, 16% ethyl acetate/hexanes to 50% ethyl acetate/hexanes) afforded 2-[4-(2-chloro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-4,4-difluoro-butyric acid methyl ester (794 mg, 40% over two steps) as an amber oil: HR-ES-MS m/z calculated for C15H14NO4ClF2 [M+H]+ 346.0652, observed 346.0651.

Provenance & Evidence