Efficient chemical fixation of CO2 to form switchable ionic liquid to synthesize benzimidazolones under mild conditions

The construction of the C-N bond using CO2 as sustainable C1 feedback can be considered as a promising and green system for the synthesis of N-containing compounds and is receiving more and more research interest. In this work, we reported a novel pathway to synthesize benzimidazolone derivatives via the carbonylation of ophenylenediamines with CO2 under mild conditions (e.g., 50 degrees C, 0.5 MPa) in the presence of 1,5-diazabicyclo [4.3.0]non-5-ene (DBN). In this progress, the DBN, acting as superbase, could form strong intermolecular hydrogen bonds with o-phenylenediamines. The CO2 was chemically fixed to form switchable ionic liquids (SILs). Then, CH2Br2 as a dehydrant easily involved parallel attack carbamates salts to form leaving group. To the best of our knowledge, this protocol provides a sustainable technique for the production of benzimidazolones under mild conditions.

Automated summary

The synthesis of benzimidazolone derivatives via the carbonylation of ophenylenediamines with CO2 under mild conditions using DBN as a superbase and the formation of switchable ionic liquids provides a sustainable technique for the production of benzimidazolones.