1: hydrazine hydrate / N,N-dimethyl-formamide / 20 h / 0 °C / Inert atmosphere 2: acetic anhydride; acetic acid / 120 h / 23 °C / Inert atmosphere 3: water / Raney nickel / methanol / 23 °C 4: hydrazine hydrate / N,N-dimethyl-formamide / 18 h / 23 °C / Inert atmosphere View Scheme

1: hydrazine hydrate / N,N-dimethyl-formamide / 20 h / 0 °C / Inert atmosphere 2: acetic anhydride; acetic acid / 120 h / 23 °C / Inert atmosphere 3: water / Raney nickel / methanol / 23 °C 4: hydrazine hydrate / N,N-dimethyl-formamide / 18 h / 23 °C / Inert atmosphere 5: lithium hexamethyldisilazane / N,N-dimethyl-formamide; tetrahydrofuran / 1.58 h / 20 °C / Inert atmosphere 6: toluene-4-sulfonic acid / tetrahydrofuran; methanol / 1 h / 0 - 5 °C View Scheme