3-(2-Chloro-phenoxy)-4-(3,3-difluoro-1-methoxycarbonyl-propylamino)-but-2-enoic acid ethyl ester 在
silica gel 、 ethyl acetate hexanes 作用下,
以
乙腈 为溶剂,
反应 3.0h,
以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的产率得到2-[4-(2-Chloro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-4,4-difluoro-butyric acid methyl ester