1: 62 percent / triethylamine / benzene / 10 h / Heating 2: 70 percent / hydrazine hydrate / Raney nickel / methanol / 4 h / Ambient temperature 3: 69 percent / CHCl3 / Ambient temperature 4: 60 percent / acetic anhydride / 7.5 h / Heating View Scheme

1: 62 percent / triethylamine / benzene / 10 h / Heating 2: 70 percent / hydrazine hydrate / Raney nickel / methanol / 4 h / Ambient temperature 3: 69 percent / CHCl3 / Ambient temperature 4: 60 percent / acetic anhydride / 7.5 h / Heating View Scheme

acetic anhydride 7.5 h; Heating;