Synthesis
The general procedure for the synthesis of 5-fluoro-1H-benzo[d]imidazol-2(3H)-ones from carbon dioxide and 4-fluoro-1,2-benzenediamine was as follows: 4-fluoro-1,2-benzenediamine (1 mmol), Catalyst I (0.15 mmol), and N-methylpyrrolidone (NMP, 1 mL) were added in a Schlenk tube and placed in a magnetic stirrer. Carbon dioxide (1 atm) was passed into the reaction system via a balloon and the reaction mixture was subsequently stirred at 140 °C for 24 hours. The reaction progress was monitored periodically by GC, LC, GC-MS or NMR. For the reaction under high pressure conditions, the reaction was carried out by placing the reactants in a Teflon vessel and then in a stainless steel autoclave and passing carbon dioxide up to 20 atm.
References
[1] Angewandte Chemie - International Edition, 2012, vol. 51, # 27, p. 6700 - 6703
[2] Chemistry - An Asian Journal, 2016, vol. 11, # 19, p. 2735 - 2740
[3] ACS Catalysis, 2013, vol. 3, # 9, p. 2076 - 2082
[4] Catalysis Today, 2014, vol. 226, p. 160 - 166
