234449-90-2Relevant academic research and scientific papers
Zirconium Oxide-Catalyzed Direct Amidation of Unactivated Esters under Continuous-Flow Conditions
Rashed, Md. Nurnobi,Masuda, Koichiro,Ichitsuka, Tomohiro,Koumura, Nagatoshi,Sato, Kazuhiko,Kobayashi, Shū
, p. 2529 - 2535 (2021/02/01)
A sustainable and environmentally benign direct amidation reaction of unactivated esters with amines has been developed in a continuous-flow system. A commercially available amorphous zirconium oxide was found to be an efficient catalyst for this reaction. While the typical amidation of esters with amines requires a stoichiometric amount of a promoter or metal activator, the present continuous-flow method enabled the direct amidation reaction under additive-free conditions with an extensive diversity towards various functional groups. High yields of the products were obtained with a nearly equimolar proportion of starting materials to reduce byproduct formation, which renders this process applicable for use in a sequential-flow system. (Figure presented.).
A facile, one-pot procedure for the conversion of aromatic aldehydes to esters, as well as thioesters and amides, via acyl hydrazide intermediates
Maruani, Antoine,Lee, Maximillian T. W.,Watkins, George,Akhbar, Ahmed R.,Baggs, Henry,Shamsabadi, André,Richards, Daniel A.,Chudasama, Vijay
, p. 3372 - 3376 (2016/01/16)
Herein we present an efficient method for the synthesis of esters from aromatic aldehydes via readily accessible acyl hydrazides. The developed reaction protocol is shown to be tolerant of a range of aromatic aldehydes, bearing various functionalities, as well as being amenable to the synthesis of thioesters and amides.
Direct amide synthesis from equimolar amounts of carboxylic acid and amine catalyzed by mesoporous silica SBA-15
Tamura, Mizuki,Murase, Daisuke,Komura, Kenichi
supporting information, p. 769 - 776 (2015/03/14)
Direct amide synthesis from equimolar amounts of carboxylic acid and amine using mesoporous silica as a versatile heterogeneous catalyst is reported.
Mechanistic investigation of the ruthenium-N-heterocyclic-carbene-catalyzed amidation of amines with alcohols
Makarov, Ilya S.,Fristrup, Peter,Madsen, Robert
supporting information, p. 15683 - 15692 (2013/01/16)
The mechanism of the ruthenium-N-heterocyclic-carbene-catalyzed formation of amides from alcohols and amines was investigated by experimental techniques (Hammett studies, kinetic isotope effects) and by a computational study with dispersion-corrected density functional theory (DFT/M06). The Hammett study indicated that a small positive charge builds-up at the benzylic position in the transition state of the turnover-limiting step. The kinetic isotope effect was determined to be 2.29(±0.15), which suggests that the breakage of the C-H bond is not the rate-limiting step, but that it is one of several slow steps in the catalytic cycle. Rapid scrambling of hydrogen and deuterium at the α position of the alcohol was observed with deuterium-labeled substrates, which implies that the catalytically active species is a ruthenium dihydride. The experimental results were supported by the characterization of a plausible catalytic cycle by using DFT/M06. Both cis-dihydride and trans-dihydride intermediates were considered, but when the theoretical turnover frequencies (TOFs) were derived directly from the calculated DFT/M06 energies, we found that only the trans-dihydride pathway was in agreement with the experimentally determined TOFs. On the right pathway: Experimental and theoretical investigations indicate that the Ru-catalyzed amidation of amines with alcohols (see scheme) proceeds by alcohol coordination, β-hydride elimination, nucleophilic attack, and β-hydride elimination to the amide. Copyright
