Fast condensation of cyclohexanone with 2-aminobenzonitrile at room temperature catalysed by an N-heterocyclic carbene

A fast condensation of cyclohexanone with 2-aminobenzonitrile catalysed by N-heterocyclic carbene 1,3-dipropylimidazole-2-ylidene (NHC-PPIm) at room temperature was discovered. NHC-PPIm was prepared via concentration of a 1,3-dipropylimidazolium hydroxide aqueous solution and showed excellent catalytic activity in the condensation reaction for the synthesis of quinazolinone. A possible catalytic mechanism was proposed based on the umpolung of cyclohexanone.

► Synthesis of quinazolinone via condensation of cyclohexanone with 2-aminobenzonitrile.
► An NHC was produced via concentration of a [PPIm][OH] aqueous solution.
► The NHC showed high catalytic activity in the condensation reaction.
► A possible catalytic mechanism was proposed based on the umpolung of cyclohexanone.