1: (R)-alanine With lithium aluminium tetrahydride in tetrahydrofuran 12 h; Heating / reflux; 2: With sodium hydroxide; water in tetrahydrofuran T=0 - 20°C; 0.166667 h; 3: di-tert-butyl dicarbonate in tetrahydrofuran; dichloromethane; water T=60°C; 6 h;