boron tribromide in dichloromethane 48 h; Ambient temperature;

molecular sieve in N,N-dimethyl-formamide Heating;

1: 69 percent / molecular sieves / dimethylformamide / Heating 2: 91 percent / dimethylformamide / 5 h / Heating 3: 64 percent / 98percent hydrazine / ethanol / 0.25 h / Heating 4: BBr3 / CH2Cl2 / 48 h / Ambient temperature View Scheme

1: 69 percent / molecular sieves / dimethylformamide / Heating 2: 91 percent / dimethylformamide / 5 h / Heating 3: 64 percent / 98percent hydrazine / ethanol / 0.25 h / Heating View Scheme

1: 69 percent / molecular sieves / dimethylformamide / Heating 2: 91 percent / dimethylformamide / 5 h / Heating 3: 64 percent / 98percent hydrazine / ethanol / 0.25 h / Heating 4: 17 percent / 25percent aq. NaOH / ethanol / 5 h / Heating 5: BBr3 / CH2Cl2 / 48 h / Ambient temperature View Scheme

1: 69 percent / molecular sieves / dimethylformamide / Heating 2: 91 percent / dimethylformamide / 5 h / Heating 3: 64 percent / 98percent hydrazine / ethanol / 0.25 h / Heating 4: 17 percent / 25percent aq. NaOH / ethanol / 5 h / Heating View Scheme

1: 69 percent / molecular sieves / dimethylformamide / Heating 2: 92 percent / cuprous chloride / dimethylformamide / 5 h / Heating 3: 67.8 percent / 98percent hydrazine / ethanol / 0.25 h / Heating 4: BBr3 / CH2Cl2 / 48 h / Ambient temperature View Scheme

1: 69 percent / molecular sieves / dimethylformamide / Heating 2: 92 percent / cuprous chloride / dimethylformamide / 5 h / Heating 3: 67.8 percent / 98percent hydrazine / ethanol / 0.25 h / Heating View Scheme

1: 69 percent / molecular sieves / dimethylformamide / Heating 2: 92 percent / cuprous chloride / dimethylformamide / 5 h / Heating View Scheme