1.1: sodium hydroxide / tetrahydrofuran; water / 0.5 h / 0 °C 1.2: 48 h / 20 °C 1.3: 3 - 4 h 2.1: 2-chloro-1-methyl-pyridinium iodide; triethylamine / dichloromethane / 48 h / 20 °C / Inert atmosphere View Scheme

1: trans-(R)-4-(1-aminoethyl)cyclohexanecarboxylic acid With sodium hydroxide in tetrahydrofuran; water T=0°C; 0.5 h; 2: di-tert-butyl dicarbonate in tetrahydrofuran; water T=20°C; 48 h; 3: With hydrogenchloride in water 3 - 4 h;