1: diethyl ether / Ambient temperature 2: 65 percent / 70 percent HClO4, acetic anhydride / 2 h / 60 °C 3: 68 percent / acetonitrile / Ambient temperature View Scheme

1: diethyl ether / Ambient temperature 2: 65 percent / 70 percent HClO4, acetic anhydride / 2 h / 60 °C 3: 22 percent / N2H4*H2O (80percent) / Ambient temperature View Scheme

1: diethyl ether / Ambient temperature 2: 65 percent / 70 percent HClO4, acetic anhydride / 2 h / 60 °C 3: 50 percent / NaN3 / acetonitrile / 24 h / Ambient temperature View Scheme

1: diethyl ether / Ambient temperature 2: 65 percent / 70 percent HClO4, acetic anhydride / 2 h / 60 °C 3: 33 percent / I2, aq. NH3 / acetonitrile / Ambient temperature; other ring expansion reaction with NaN3 View Scheme

1: diethyl ether / Ambient temperature 2: 65 percent / 70 percent HClO4, acetic anhydride / 2 h / 60 °C 3: 21 percent / aq. NH3 (28percent) / Ambient temperature View Scheme