Practical carbocatalysis by graphene oxide nanosheets in aqueous medium towards the synthesis of diversified dibenzo[1,4]diazepine scaffolds

GO nanosheets are found to be an efficient recyclable carbocatalyst for the construction of diversified dibenzo[1,4]diazepine nuclei starting from o -phenylenediamine, various aldehyde/ketone and 1,3-diketo compounds in aqueous medium. This new metal free synthetic protocol also facilitated the formation of coumarine and quinolinone fused novel dibenzo[1,4]diazepines and provided an excellent yield of the corresponding products. In addition, when a substrate contains both the aldehyde and ketone functionality, the reacton offers dibenzo[1,4]diazepines resulting from the chemoselective aldehyde adduct. Metal free green protocol in aqueous medium. Use of GO nanosheets as exclusive heterogeneous catalyst. Almost intact catalytic activity upto the 5th run. Mild reaction conditions preserve sensitive structural moeities.