1: NaBH4, BF3*Et2O / tetrahydrofuran / 1.) 0 deg C, 7 h, 2.) room temperature, 50 h 2: aq. H2SO4 / 0.42 h 3: formic acid, water / 3 h / Heating View Scheme

1: NaBH4, BF3*Et2O / tetrahydrofuran / 1.) 0 deg C, 7 h, 2.) room temperature, 50 h 2: aq. H2SO4 / 0.42 h View Scheme

1: NaBH4, BF3*Et2O / tetrahydrofuran / 1.) 0 deg C, 7 h, 2.) room temperature, 50 h 2: aq. H2SO4 / 0.42 h 3: formic acid, water / 3 h / Heating 4: 70 percent / ClCOOCH2CCl3 / benzene / 2 h / Heating 5: 41 percent / dimethylformamide / 3 h / 80 °C 6: 1.25 g / H2NNH2*H2O / methanol / 5 h / 60 °C View Scheme