in ethanol 1 h;

1: 80 percent / 60percent hydrazine hydrate / methanol / 0.33 h / Heating 2: 70 percent / ethanol / Heating 3: 76 percent / ethanol / 1 h View Scheme

1: 80 percent / Br2 / acetic acid / 1 h / Ambient temperature 2: 80 percent / 60percent hydrazine hydrate / methanol / 0.33 h / Heating 3: 70 percent / ethanol / Heating 4: 76 percent / ethanol / 1 h View Scheme

1: 70 percent / ethanol / Heating 2: 76 percent / ethanol / 1 h View Scheme