A solution of methyl [(2S)-1-(biphenyl-4-ylcarbonyl)-4-oxopyrrolidin-2-yl]acetate (43 mg, 0.13 mmol), hydroxylamine methyl ether hydrochloride (32 mg, 0.38 mmol) and triethylamine (53 μl, 0.38 mmol) in chloroforme (3 ml) was stirred at 70° C. for 5 days. The reaction mixture was diluted with dichloromethane and washed with HCl 1N. The organic phase was dried (MgSO4) and concentrated to afford methyl [(2S,4EZ)-1-(biphenyl-4-yl-carbonyl)--4-(methoxyimino)pyrrolidin-2-yl]acetate (40 mg). Yield: 62%. HPLC purity: 94%
