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Direct Synthesis of Amides from Oxidative Coupling of Benzyl Alcohols or Benzylamines with N ‐Substituted Formamides Using a Cu‐Fe‐Based Heterogeneous Catalyst
Author(s) -
Gupta Shyam Sunder R.,
Nakhate Akhil V.,
Deshmukh Gunjan P.,
Periasamy Selvakannan,
Samudrala Priya S.,
Bhargava Suresh K.,
Lakshmi Kantam Mannepalli
Publication year - 2018
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201801297
Subject(s) - formamides , benzyl alcohol , catalysis , chemistry , amide , oxidative coupling of methane , x ray photoelectron spectroscopy , benzaldehyde , organic chemistry , inorganic chemistry , chemical engineering , engineering
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 N 2 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.