Synthesis
2.1A. General procedure for the synthesis of 5-bromo-1,3-dihydrobenzimidazol-2-one: 4.29 g (26.46 mmol) of N,N'-carbonyldiimidazole (CDI) was added to 95 mL of N,N-dimethylformamide (DMF) solution containing 4.5 g (24.05 mmol) of 4-bromobenzene-1,2-diamine. The reaction mixture was stirred at 80 °C for 5 hours. After completion of the reaction, the mixture was poured into water and the precipitate formed was filtered out. The precipitate was washed three times with water and subsequently dried in a circulating air dryer at 60 °C. Yield: 4.6 g (90% of theoretical yield); Molecular formula: C7H5BrN2O (M = 213.03); Calculated value: molecular ion peak (M + H)+: 213/215; Measured value: molecular ion peak (M + H)+: 213/215; Rf-value: 0.5 (silica gel, dichloromethane/methanol = 10:1).
References
[1] Journal of Medicinal Chemistry, 2016, vol. 59, # 15, p. 7188 - 7211
[2] Patent: US2005/267115, 2005, A1. Location in patent: Page/Page column 35
[3] Patent: WO2005/103029, 2005, A1. Location in patent: Page/Page column 75
[4] Journal of Medicinal Chemistry, 2006, vol. 49, # 12, p. 3719 - 3742
[5] Patent: WO2011/130628, 2011, A1. Location in patent: Page/Page column 231
