Abstract
Here we report Ni-nanoparticles as reusable catalysts for reductive N-alkylation of amides. These Ni-nanoparticles based catalysts have been prepared by the template synthesis of tartaric acid and 2-methyl imidazole ligated Ni-complex on SiO2 and subsequent pyrolysis under argon. Applying optimal Ni-nanostructured catalyst, N-alkylation of aromatic and heterocyclic primary amides with different aldehydes in presence of molecular hydrogen was performed to access structurally diverse N-alkylated amides in good to excellent yields. In addition, the applicability of this N-alkylation protocol has been demonstrated for the selective functionalization of primary amide group in Levetiracetam drug.
Reductive N-alkylation of amides with aldehydes is performed using silica supported graphitic shell encapsulated Ni-nanoparticles in presence of molecular hydrogen. [Display omitted]
•The preparation of 3d-metal based core-shell nanoparticles-based catalysts for the synthesis and functionalization of essential compounds is of central importance and attracts interest.•Immobilization and subsequent pyrosis of Ni-tartaric acid and 2-methylimidazole on SiO2 produced graphitic shell encapsulated Ni-nanoparticles, which found to be excellent catalysts for reductive N-alkylation of primary amides.•Applying these catalysts, aromatic and heterocyclic primary amides were selectively N-alkylated with aldehydes to produce N-alkylated amides in good to excellent yields.