No abstract

An environmentally friendly, inexpensive, carbocatalyst, graphene oxide (GO) promoted efficient, metal‐free transamidation of various carboxamides with aliphatic, cyclic, and aromatic amines is demonstrated. The protocol is equally applicable to phthalimide, urea, and thioamide determining its adaptability. The oxygenated functionalities such as carbonyl (−C=O), epoxy (−O−), carboxyl (−COOH) and hydroxyl (−OH), present on graphene oxide surface impart acidic properties to the catalyst. The graphene oxide being heterogeneous in nature, work efficiently under solvent‐free reaction conditions providing desired products in good to excellent yields. The one‐pot synthesis of 2,3‐Dihydro‐5H‐benzo[b]‐1,4‐thiazepin‐4‐one moiety by GO catalyzed Aza Michael addition followed by intramolecular transamidation is also described. A plausible reaction mechanistic pathway involving H‐bonding is discussed. The graphene oxide can be recycled and reused up to five cycles without much loss in catalytic activity.magnified image

Herein, a highly efficient, metal‐free, carbocatalyst, graphene oxide (GO) has been screened for the direct amidation of carboxylic acids with amines. The present catalytic system accessed a broad range of substrates to afford amides in excellent yields. A plausible reaction mechanism involving H‐bonding with the reactants is described. Furthermore, the GO can be recycled and reused up to five cycles without substantial loss in catalytic activity.

Sodium sulfate–hydrogen peroxide–sodium chloride adduct: selective protocols for anilines and sulfides oxidation.

No abstract