Direct Synthesis of Amides from Oxidative Coupling of Benzyl Alcohols or Benzylamines with N-Substituted Formamides Using a Cu-Fe-Based Heterogeneous Catalyst

Shyam Sunder R. Gupta, Akhil V. Nakhate, Gunjan P. Deshmukh, Selvakannan Periasamy, Priya S. Samudrala, Suresh K. Bhargava, Mannepalli Lakshmi Kantam

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4 Citations (Scopus)

Abstract

Here we report a highly active and recyclable Cu−Fe based heterogeneous catalytic system for the oxidative coupling of benzyl alcohols as well as benzylamines with N-substituted formamides. The Cu−Fe Metal Oxide (Cu−Fe MO) catalyst was prepared by a co-precipitation method and was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Energy-dispersive X-ray spectroscopy (EDS), Field Emission Gun-Scanning Electron Microscopy (FEG-SEM) and N2 physical adsorption techniques. The catalytic activity of the as-prepared Cu−Fe MO catalyst was evaluated towards amidation reactions and a broad spectrum of aromatic amides have been synthesized in good to moderate yields by oxidative coupling of benzyl alcohols or benzylamines bearing various substituents with N-substituted formamides. The control experiments revealed that the benzyl alcohol or benzylamine gets converted to an acyl radical and on the other side the N-substituted formamides form an aminyl radical in presence of the catalyst and tert-Butyl hydroperoxide (TBHP). Successive coupling of the in-situ generated acyl and aminyl radicals affords the desired product amide. Furthermore, the heterogeneous Cu−Fe MO catalyst recycled for four times towards the amidation of benzyl alcohol and the fidelity of the spent catalyst has been confirmed by XRD analysis.

Original languageEnglish
Pages (from-to)8436-8443
Number of pages8
JournalChemistrySelect
Volume3
Issue number29
DOIs
Publication statusPublished - 7 Aug 2018
Externally publishedYes

Keywords

  • Amidation
  • Benzyl alcohols
  • Benzylamines
  • Cu−Fe metal oxide
  • DMF

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