lithium azide; ammonium chloride in N,N-dimethyl-formamide T=110°C; 18 h;

silica gel; trifluoroacetic acid in methanol; chloroform

1: 36 percent / trimethylsilyl trifluoromethanesulfonate / acetonitrile / 4 h / Heating 2: 22 percent / NH3 / methanol / 15 h / 23 °C View Scheme

1: 85 percent / pyridine / 0.5 h / 100 °C 2: 75 percent / (diethylamido)sulfur trifluoride / CH2Cl2 / 0.25 h / -78 °C 3: 65 percent / NaN3 / dimethylformamide; H2O / 48 h / Heating 4: 55 percent / 80percent aq. AcOH / 2 h / Heating View Scheme

1: 1.) mercuric bromide, cadmium carbonate, 2.) methanol / 1.) toluene, reflux, 24 h, 2.) H2O, 30 min 2: 1.) 2 M BCl3, 2.) CH3OH / 1.) CH2Cl2, -78 deg C, 5 h, 2.) CH2Cl2, from -78 deg C to RT, 1 h 3: 9 percent / 2-chloro-1,1,2-trifluorotriethylamine / dimethylformamide / 0.5 h / 70 °C 4: 42 percent / LiN3, NH4Cl / dimethylformamide / 18 h / 110 °C View Scheme

1: 5 h / Heating 2: SnCl4 / 1,2-dichloro-ethane / 5 h / Ambient temperature 3: NH3 / methanol / 12 h / Ambient temperature View Scheme

1: 36 percent / trimethylsilyl trifluoromethanesulfonate / acetonitrile / 4 h / Heating 2: 22 percent / NH3 / methanol / 15 h / 23 °C View Scheme