1: 1) anhydrous sodium sulfite 2) dimethylformamide, thionyl chloride / 1) water, reflux, 24 h 2) benzene, reflux, 4h 2: 70 percent / Sodium azide / acetone; H2O / 12 h / Ambient temperature 3: 46 percent / 0 h / 400 °C / 3.7 - 3.8 Torr View Scheme

1: 1) anhydrous sodium sulfite 2) dimethylformamide, thionyl chloride / 1) water, reflux, 24 h 2) benzene, reflux, 4h 2: 70 percent / Sodium azide / acetone; H2O / 12 h / Ambient temperature 3: 3.8 percent / 0 h / 400 °C / 3.7 - 3.8 Torr View Scheme