Oxidized Carbon Black as Catalyst for the Enamine Formation in Solvent-Free Conditions: A Green Strategy to Build the Benzodiazepine Scaffold

Oxidized carbon black efficiently catalyzed addition of amines to 1,3-dicarbonyl compounds under solvent-free conditions at room temperature. This methodology is eco-friendly and cheap, with a very easy work up and the possibility to recover and recycle the catalyst. Finally, the elaborated methodology can be conveniently exploited for the synthesis of 1,5-benzodiazepine.