GENERAL METHOD: NaOH (2.4 g, 0.06 mol) was dissolved in water (100 mL) and stirred under cooling in an ice bath. To this solution was added ethyl 2-(2-aminothiazol-4-yl)-2-(trans)-hydroxyiminoacetate or ethyl 2-(2-aminothiazol-4-yl)-2-(cis)-hydroxyiminoacetate (10.76 g, 0.05 mol). The reaction mixture was stirred at 15-20°C for 2-3 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure. The residual solid was dissolved in water (100 mL), decolorized by the addition of Norit (1.0 g) and filtered. Glacial acetic acid was slowly added dropwise to the filtrate under stirring until the pH reached neutral. The resulting precipitate was collected by filtration, washed with water and finally the product was purified by two ethanol recrystallizations.
