1: 76 percent / bromine / CH2Cl2 / 2.5 h / -78 °C 2: 94 percent / 1,5-diazabicyclo<5.4.0>undec-5-ene (DBU) / tetrahydrofuran / 24 h / 1) ice bath 2) room temperature 3: 51 percent / anhydrous hydrazine / CH2Cl2 / 24 h / Ambient temperature 4: 92 percent / NaN3 / various solvent(s) / 0.75 h View Scheme