1: 99 percent / diphenyl phosphorazidate, triethylamine / dimethylformamide / 17 h / 0 - 20 °C 2: 87 percent / trifluoroacetic acid (TFA) / CH2Cl2 / 0.75 h / 0 - 20 °C 3: 96 percent / pyridine 4: 95 percent / diphenyl phosphorazidate, triethylamine / dimethylformamide / 17 h / 0 - 20 °C 5: 100 percent / trifluoroacetic acid (TFA) / CH2Cl2 6: 91 percent / pyridine / 12 h 7: H2, HCl / 10percent Pd/C / methanol View Scheme

1: 98 percent / DCC, DMAP / CHCl3 / 24.5 h / 0 - 20 °C 2: 82 percent / H2, NH3 / Raney Ni / methanol; H2O / 2.5 h / 2585.7 Torr 3: 88 percent / DCC, DMAP / CHCl3 / 12.2 h / 0 - 20 °C 4: 84 percent / H2, 0.1 N aq. HCl / 10percent Pd/C / methanol / 7.5 h / 760 Torr View Scheme

 

Multi-step reaction with 2 steps 1: 98 percent / DCC, DMAP / CHCl3 / 24.5 h / 0 - 20 °C2: 82 percent / H2, NH3 / Raney Ni / methanol; H2O / 2.5 h / 2585.7 Torr  

With  4-(N,N-dimethlyamino)pyridine; dicyclohexyl-carbodiimide in  chloroform T=0 - 20°C; 12.2 h;   

Multi-step reaction with 3 steps 1: 98 percent / DCC, DMAP / CHCl3 / 24.5 h / 0 - 20 °C2: 82 percent / H2, NH3 / Raney Ni / methanol; H2O / 2.5 h / 2585.7 Torr3: 88 percent / DCC, DMAP / CHCl3 / 12.2 h / 0 - 20 °C