Synthesis
Example 138: General procedure for the synthesis of 5,6-dichloro-1H-benzo[d]imidazol-2-amine from 4,5-dichloro-1,2-benzenediamine and cyanogen bromide: Cyanogen bromide (0.063 g, 0.6 mmol) was added to a mixture of acetonitrile (10 mL) and water (0.81 g, 0.562 mmol) of 4,5-dichlorobenzene-1,2-diamine (0.81 g, 0.562 mmol) at 0 °C. (2 mL) in a mixed solution of acetonitrile (10 mL) and water (2 mL). The reaction mixture was gradually warmed to room temperature with continuous stirring for 14 hours. Subsequently, saturated aqueous sodium bicarbonate solution (50 mL) was added to the reaction mixture and shaken thoroughly. The resulting solid was collected by filtration, washed with water and dried under reduced pressure to afford 5,6-dichloro-1H-benzo[d]imidazol-2-amine 0.43 g in 50% yield. Mass spectrometry (EI) analysis showed a molecular ion peak (MH+) of 203.
References
[1] Journal of Medicinal Chemistry, 1995, vol. 38, # 20, p. 4098 - 4105
[2] Journal of Medicinal Chemistry, 1998, vol. 41, # 8, p. 1252 - 1262
[3] Bioorganic and medicinal chemistry letters, 2002, vol. 12, # 16, p. 2221 - 2224
[4] Patent: WO2008/42282, 2008, A2. Location in patent: Page/Page column 208
[5] Angewandte Chemie - International Edition, 2012, vol. 51, # 41, p. 10364 - 10367
