99175-62-9Relevant academic research and scientific papers
Pyrazine Radical Cations as a Catalyst for the Aerobic Oxidation of Amines
Brisar, Rok,Hollmann, Dirk,Mejia, Esteban
, p. 5391 - 5398 (2017/10/06)
An efficient and green synthetic method for the preparation of N,N-disubstituted tetramethylpyrazinium radical cations was developed, which does not require any solvent or strong alkylating agents. The investigation by UV/Vis and electron paramagnetic res
Iridium-catalyzed condensation of amines and vicinal diols to substituted piperazines
Lorentz-Petersen, Linda L. R.,Nordstrom, Lars Ulrik,Madsen, Robert
, p. 6752 - 6759 (2013/01/15)
A straightforward procedure is described for the synthesis of piperazines from amines and 1,2-diols. The heterocyclization is catalyzed by [Cp*IrCl2]2 and sodium hydrogen carbonate and can be achieved with either toluene or water as solvent. The transformation does not require any stoichiometric additives and only produces water as the byproduct. The reaction can be performed between a 1,2-diamine and a 1,2-diol or by a double condensation between a primary alkylamine and a 1,2-diol. At least one substituent is required on the piperazine ring to achieve the cyclization in good yield. The mechanism is believed to involve dehydrogenation of the 1,2-diol to the α-hydroxy aldehyde, which condenses with the amine to form the α-hydroxy imine. The latter rearranges to the corresponding α-amino carbonyl compound, which then reacts with another amine followed by reduction of the resulting imine. Piperazines are prepared by [Cp*IrCl 2]2-catalyzed heterocyclization of 1,2-diols with either 1,2-diamines or primary alkylamines. The reaction is performed in toluene or water and requires no stoichiometric additive. The key step in the mechanism is believed to be the isomerization of an α-hydroxy imine to the corresponding α-amino carbonyl compound. Copyright
