29897-82-3Relevant articles and documents
Using a two-step hydride transfer to achieve 1,4-reduction in the catalytic hydrogenation of an Acyl pyridinium cation
Shaw, Anthony P.,Ryland, Bradford L.,Franklin, Mary J.,Norton, Jack R.,Chen, Judy Y.-C.,Hall, Michelle Lynn
, p. 9668 - 9674 (2008)
(Chemical Equation Presented) The stoichiometric reduction of N-carbophenoxypyridinium tetraphenylborate (6) by CpRu(P-P)H (Cp = η5-cyclopentadienyl; P-P = dppe, 1,2-bis(diphenylphosphino) ethane, or dppf, 1,1′-bis(diphenylphosphino)ferrocene), and Cp*Ru(P-P)H (Cp* = η5-pentamethylcyclopentadienyl; P-P = dppe) gives mixtures of 1,2- and 1,4-dihydropyridines. The stoichiometric reduction of 6 by Cp*Ru(dppf)H (5) gives only the 1,4-dihydropyridine, and 5 catalyzes the exclusive formation of the 1,4-dihydropyridine from 6, H 2, and 2,2,6,6-tetramethylpiperidine. In the stoichiometric reductions, the ratio of 1,4 to 1,2 product increases as the Ru hydrides become better one-electron reductants, suggesting that the 1,4 product arises from a two-step (e-/H?) hydride transfer. Calculations at the UB3LYP/6-311++G(3df,3pd)//UB3LYP/6-31G* level support this hypothesis, indicating that the spin density in the N-carbophenoxypyridinium radical (13) resides primarily at C4, while the positive charge in 6 resides primarily at C2 and C6. The isomeric dihydropyridines thus result from the operation of different mechanisms: the 1,2 product from a single-step H- transfer and the 1,4 product from a two-step (e-/H?) transfer.
Continuous flow heterogeneous catalytic reductive aminations under aqueous micellar conditions enabled by an oscillatory plug flow reactor
?tv?s, Sándor B.,Buchholcz, Balázs,Darvas, Ferenc,Kappe, C. Oliver,Novák, Zoltán,Sipos, Gellért,Wernik, Michaela
supporting information, p. 5625 - 5632 (2021/08/16)
Despite the fact that continuous flow processing exhibits well-established technical advances, aqueous micellar chemistry, a field that has proven extremely useful in shifting organic synthesis to sustainable water-based media, has mostly been explored under conventional batch-based conditions. This is particularly because of the fact that the reliable handling of slurries and suspensions in flow has been considered as a significant technical challenge. Herein, we demonstrate that the strategic application of an oscillatory plug flow reactor enables heterogeneous catalytic reductive aminations in aqueous micellar media enhancing mass transport and facilitating process simplicity, stability and scalability. The micellar flow process enabled a broad range of substrates, including amino acid derivatives, to be successfully transformed under reasonably mild conditions utilizing only very low amounts of Pd/C as a readily available heterogeneous catalyst. The preparative capabilities of the process along with the recyclability of the heterogenous catalyst and the aqueous reaction media were also demonstrated. This journal is
Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
Bera, Jitendra K.,Pandey, Pragati
, p. 9204 - 9207 (2021/09/20)
A terminal [Ni-OH] complex1, supported by triflamide-functionalized NHC ligands, catalyzes the hydrosilylative reduction of a range of primary amides into primary amines in good to excellent yields under base-free conditions with key functional group tolerance. Catalyst1is also effective for the reduction of a variety of tertiary and secondary amides. In contrast to literature reports, the reactivity of1towards amide reduction follows an inverse trend,i.e., 1° amide > 3° amide > 2° amide. The reaction does not follow a usual dehydration pathway.
Nickel?Copper bimetallic mesoporous nanoparticles: As an efficient heterogeneous catalyst for N-alkylation of amines with alcohols
Nasresfahani, Zahra,Kassaee, Mohamad Z.
, (2020/10/30)
A bimetallic catalyst (Ni/Cu-MCM-41) is prepared via co-condensation method. The latter is characterized by Fourier transform infrared (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), diffuse reflectance spectroscopy (DRS), and nitrogen adsorption–desorption analysis. Catalytic performance of Ni/Cu-MCM-41 is probed in N-alkylation of amines with alcohols through a hydrogen autotransfer process. Noteworthy, this catalytic system appears very efficient for synthesis of a range of secondary and tertiary amines in good to excellent isolated yields. Moreover, the catalyst is successfully recovered and reused four times without notable decrease in its activity.
