1: With hydrogenchloride in water T=0°C; 2: With sodium hydroxide in water pH=6 - 7;

1: in water 1 h; Industry scale; 2: With sodium hydroxide in water T=20°C; pH=8.4;

1: (-)-methyl (1S,2S,3R,4R)-3-[(1S)-1-(acetylamino)-2-ethylbutyl]-4-amino-2-hydroxycyclopentanecarboxylate hydrochloride With sodium hydroxide in N,N-dimethyl-formamide T=0°C; 2 h; 2: chloroformamidine hydrochloride in N,N-dimethyl-formamide T=0 - 20°C; 24.5 h; 3: With sodium hydroxide in water; N,N-dimethyl-formamide pH=8.3 - 8.5;

1.1: hydroxylamine hydrochloride; sodium hydroxide / toluene; water / 1 h / 15 - 25 °C 1.2: 10 - 25 °C 2.1: triethylamine / toluene 3.1: sodium tetrahydroborate; NiII chloride hexahydrate / methanol / -10 - -5 °C 3.2: 0 °C 3.3: pH 9 4.1: sodium hydroxide; water / tetrahydrofuran; methanol / 20 °C 5.1: hydrogenchloride / water / 0 °C 5.2: pH 6 - 7 View Scheme

1.1: hydrogenchloride / 5 h / 20 °C / |Reflux 2.1: sodium carbonate / hexane; water / 8 h / 20 °C 3.1: sodium hypochlorite / dichloromethane / 22 h / -10 - 20 °C 4.1: NiII chloride hexahydrate; sodium hydroxide; sodium tetrahydroborate / methanol / 2 h / -5 - 0 °C / |Inert atmosphere 4.2: 16 h / 20 °C 5.1: triethylamine / dichloromethane / 6 h / 20 °C 6.1: hydrogenchloride / diethyl ether / 14 h / 20 °C 7.1: sodium hydroxide / N,N-dimethyl-formamide / 2 h / 0 °C 7.2: 24.5 h / 0 - 20 °C 7.3: pH 8.3 - 8.5 View Scheme

1.1: sodium carbonate / hexane; water / 8 h / 20 °C 2.1: sodium hypochlorite / dichloromethane / 22 h / -10 - 20 °C 3.1: NiII chloride hexahydrate; sodium hydroxide; sodium tetrahydroborate / methanol / 2 h / -5 - 0 °C / |Inert atmosphere 3.2: 16 h / 20 °C 4.1: triethylamine / dichloromethane / 6 h / 20 °C 5.1: hydrogenchloride / diethyl ether / 14 h / 20 °C 6.1: sodium hydroxide / N,N-dimethyl-formamide / 2 h / 0 °C 6.2: 24.5 h / 0 - 20 °C 6.3: pH 8.3 - 8.5 View Scheme

1.1: sodium hypochlorite / dichloromethane / 22 h / -10 - 20 °C 2.1: NiII chloride hexahydrate; sodium hydroxide; sodium tetrahydroborate / methanol / 2 h / -5 - 0 °C / |Inert atmosphere 2.2: 16 h / 20 °C 3.1: triethylamine / dichloromethane / 6 h / 20 °C 4.1: hydrogenchloride / diethyl ether / 14 h / 20 °C 5.1: sodium hydroxide / N,N-dimethyl-formamide / 2 h / 0 °C 5.2: 24.5 h / 0 - 20 °C 5.3: pH 8.3 - 8.5 View Scheme