Reduced graphene oxide supported copper oxide nanocomposites: An efficient heterogeneous and reusable catalyst for the synthesis of ynones, 1,3‐diynes and 1,5‐benzodiazepines in one‐pot under sustainable reaction conditions

Abstract

A greener and efficient method for the synthesis of ynones and 1,3‐diynes using copper oxide nanoparticles (CuONPs) doped reduced graphene oxide (CuO@rGO) catalyst under palladium, ligand and solvent free conditions have been developed. The catalyst was subsequently utilized for the synthesis of biologically active 1,5‐benzodiazepines in one pot via sequential addition of acyl chlorides, terminal alkynes and o‐phenylenediamines. The methodology initially involves in situ formation of ynones which react with o‐phenylenediamines in presence of ethanol to afford a wide variety of benzodiazepines. Mild reaction conditions, good to an excellent yield of the products, cheap and recyclable catalyst make this methodology environmentally benign and sustainable.