4-Amino-3-nitrobenzonitrile → 3,4-Diaminobenzonitrile

Participants

Reaction Steps

A solution of 4-amino-3-nitrobenzonitrile (20 mmol) in MeOH (300 mL) in the presence of 5% of Pd/C (1 g) was treated with hydrogen at room temperature for 16 hours. The reaction mixture was filtered and concentrated to give 3,4-diaminobenzonitrile (2.4 g, 90% of yield), which was directly treated with formic acid (20 mL) under reflux for 4 hours. After removal of the excess formic acid, the residue was dissolved in EtOAc, washed with 10% sodium bicarbonate and brine, and dried over MgSO4. Concentration gave 5-cyanobenzimidazole (2.2 g, 85%). 1H NMR (CD3OD) δ8.39 (s, 1H), 8.05 (s, 1H), 7.76 (d, J=8.4 Hz, 1H), 7.59 (dd, J=8.4 Hz, J=1.1 Hz, 1H); MS: 144 (M+H)+.

Provenance & Evidence