Synthesis of 5-Aminobenzimidazolone-2 from 5-Nitrobenzimidazolone-2 with Catalyst Raney Ni

5-Aminobenzimidazolone-2 was prepared from 5-nitrobenzimidazolone-2 by hydrogenation under pressure with catalyst Raney Ni.The appropriate reaction conditions were as follows.The solvent was ethanol and the volume was 120 mL per mol nitro compound.The reaction temperature ranged from 90 ℃to 95℃.The pressure ranged from 2 MPa to 3 MPa.Amount of the catalyst was 4%～5%(based on the nitro compound).The Raney Ni was recycled for four times.Aminobenzimidazolone-2 was produced in 90% yield and of 99.0% purity.