1: 41 percent / triethylamine / dimethylformamide / 15 h / Ambient temperature 2: 32 percent / Zn powder / acetic acid / 1.5 h / Heating 3: 84 percent / 40percent aq. methylamine / 1 h / 100 °C 4: 48 percent / NaNO2 / acetic acid / 15 h 5: 39 percent / NH3 / ethanol / 60 h / 140 °C View Scheme

1: 41 percent / triethylamine / dimethylformamide / 15 h / Ambient temperature 2: 32 percent / Zn powder / acetic acid / 1.5 h / Heating 3: 84 percent / 40percent aq. methylamine / 1 h / 100 °C 4: 48 percent / NaNO2 / acetic acid / 15 h View Scheme