hydrazine hydrate in ethanol 0.5 h; Heating;

1: pyridine 2: 85 percent / MnO2 / CHCl3 / 3 h / Heating 3: 95 percent / 2N aq. HCl / ethanol / 3 h / Heating 4: 80 percent / MnO2 / tetrahydrofuran / 50 h / Ambient temperature View Scheme

bromine; acetic acid T=60 - 70°C; 3 h;

selenium(IV) oxide in ethanol 1 h; Heating;