6724-71-6Relevant academic research and scientific papers
Catalytic C-N Bond-Forming Reactions Enabled by Proton-Coupled Electron Transfer Activation of Amide N-H Bonds
Nguyen, Lucas Q.,Knowles, Robert R.
, p. 2894 - 2903 (2016)
Over the past three years, our group has become interested in the ability of proton-coupled electron transfer (PCET) to facilitate direct homolytic bond activations of common organic functional groups that are challenging substrates for conventional hydro
Flow synthesis of N-alkyl-5-methyl-2-pyrrolidones over Ni2P/SiO2 catalyst
Bukhtiyarova, Galina A.,Nuzhdin, Alexey L.,Shamanaev, Ivan V.,Wang, Yazhou
, (2021/09/20)
N-alkyl-5-methyl-2-pyrrolidones are an attractive alternative to the common solvent N-methyl-2-pyrrolidone (NMP) and can be used as starting materials for synthesis of various valuable chemicals. Reductive amination of alkyl levulinates derived from biomass feedstock is a promising method for production of these compounds. In the present work, N-alkyl-5-methyl-2-pyrrolidones were obtained in excellent yields by reductive amination of ethyl levulinate with alkylamines over SiO2-supported nickel phosphide in a flow reactor using molecular hydrogen as a reducing agent. At the same time, aromatic amines and 1-nitropropane give a lower yield of the corresponding pyrrolidones. The influence of the solvent nature, temperature, pressure, hydrogen and liquid flow rates on the catalyst performance was studied.
Extended Hydrogen Bond Networks for Effective Proton-Coupled Electron Transfer (PCET) Reactions: The Unexpected Role of Thiophenol and Its Acidic Channel in Photocatalytic Hydroamidations
Berg, Nele,Bergwinkl, Sebastian,Nuernberger, Patrick,Horinek, Dominik,Gschwind, Ruth M.
supporting information, p. 724 - 735 (2021/02/01)
Preorganization and aggregation in photoredox catalysis can significantly affect reactivities or selectivities but are often neglected in synthetic and mechanistic studies, since the averaging effect of flexible ensembles can effectively hide the key activation signatures. In addition, aggregation effects are often overlooked due to highly diluted samples used in many UV studies. One prominent example is Knowles's acceleration effect of thiophenol in proton-coupled electron transfer mediated hydroamidations, for which mainly radical properties were discussed. Here, cooperative reactivity enhancements of thiophenol/disulfide mixtures reveal the importance of H-bond networks. For the first time an in-depth NMR spectroscopic aggregation and H-bond analysis of donor and acceptor combined with MD simulations was performed revealing that thiophenol acts also as an acid. The formed phosphate-H+-phosphate dimers provide an extended H-bond network with amides allowing a productive regeneration of the photocatalyst to become effective. The radical and acidic properties of PhSH were substituted by Ph2S2 and phosphoric acid. This provides a handle for optimization of radical and ionic channels and yields accelerations up to 1 order of magnitude under synthetic conditions. Reaction profiles with different light intensities unveil photogenerated amidyl radical reservoirs lasting over minutes, substantiating the positive effect of the H-bond network prior to radical cyclization. We expect the presented concepts of effective activation via H-bond networks and the reactivity improvement via the separation of ionic and radical channels to be generally applicable in photoredox catalysis. In addition, this study shows that control of aggregates and ensembles will be a key to future photocatalysis.
One-pot synthesis of pyrrolidones from levulinic acid and amines/nitroarenes/nitriles over the Ir-PVP catalyst
Chaudhari, Chandan,Nagaoka, Katsutoshi,Nishida, Yoshihide,Sato, Katsutoshi,Shiraishi, Masaya
supporting information, p. 7760 - 7764 (2020/11/27)
The synthesis of pyrrolidones via reductive amination of levulinic acid with aniline was examined over polypyrrolidone-stabilized metal nanoparticle catalysts. Among them, Ir metal was the most effective and applicable for the reductive amination of levulinic acid with nitroarenes/nitriles. Importantly, this catalyst was used for the one-pot synthesis of the anti-inflammatory drug indoprofen from 2-formylbenzoic acid and 2-(4-nitrophenyl)propanoic acid.
Reductive amination of levulinic acid to N-substituted pyrrolidones over RuCl3 metal ion anchored in ionic liquid immobilized on graphene oxide
Raut, Amol B.,Shende, Vaishali S.,Sasaki, Takehiko,Bhanage, Bhalchandra M.
, p. 206 - 214 (2020/02/15)
Reductive amination of biomass derived Levulinic acid (LA) for the synthesis of N-substituted pyrrolidones is one of the highly attractive routes for biomass valorization. The supported homogeneous metal precursor into the solid surface is an important context in the field of catalysis because these types of catalysts provide the heterogeneous nature and meet the needs of recyclability. Herein, we have reported a synthesis of catalyst with ruthenium ion supported on ionic liquid immobilized into graphene oxide (Ru?GOIL) and its application for reductive amination reaction. Synthesized catalyst is characterized using different analytical techniques such as FT-IR, XRD, XPS, TGA, FEG-SEM, TEM and EXAFS analysis. The prepared Ru?GOIL found to be highly effective for reductive amination of LA and under these optimized conditions various N-substituted pyrrolidones derivatives were synthesized in excellent yield (78–93%). Ru?GOIL catalyst demonstrated great catalytic performance for reductive amination reaction of LA giving good turnover frequency (TOF = 62 h?1) value in comparison with other catalysts. The Ru?GOIL catalyst was recycled for six reaction runs with slight drop-in activity after 4th cycle. Practical applicability of the developed catalyst was successfully demonstrated by direct transformation of biomass waste (rice husk and wheat straw) derived LA to N-substituted pyrrolidones.
Investigation towards the reductive amination of levulinic acid by B(C6F5)3/hydrosilane system
He, Jianghua,Wang, Tianlong,Xu, Hai,Zhang, Yuetao
, (2020/08/11)
The selective transformation of the renewable biomass resources into the highly value-added platform chemicals is essentially important for sustainable chemistry. Here we report a simple and highly efficient strategy for the synthesis of N-heterocyclic co
Ambient reductive synthesis of N-heterocyclic compounds over cellulose-derived carbon supported Pt nanocatalyst under H2atmosphere
Wu, Yunyan,Wu, Yunyan,Zhao, Yanfei,Zhao, Yanfei,Wang, Huan,Wang, Huan,Zhang, Fengtao,Zhang, Fengtao,Li, Ruipeng,Li, Ruipeng,Xiang, Junfeng,Wang, Zhenpeng,Han, Buxing,Liu, Zhimin
, p. 3820 - 3826 (2020/07/06)
N-heterocyclic compounds are important chemicals, and their reductive synthesis using H2 under mild conditions is attractive but challenging. Herein, we report chemoselective hydrogenation of 2-nitroacylbenzenes to 2,1-benzisoxazoles under ambient conditions for the first time, wihch is achieved over cellulose-derived carbon (c-C) supported Pt nanocatalyst (Pt/c-C), and a series of 2,1-benzisoxazoles can be obtained in excellent yields. Pt/c-C also shows high performance for ambient reductive amination of levulinic acid with H2, accessing various pyrrolidones in excellent yields. The systematic studies indicated that the c-C support played multiple roles in catalysis with enhancing electron density of the Pt nanoparticles and activating reactant molecules. Especially, the O-containing groups on the c-C surface provided the c-C support with both acid and base features, thus endowing Pt/c-C with high performances. This work provides an accessible and highly efficient catalyst for reductive synthesis of N-heterocycles using H2 under ambient conditions, which may have promising applications.
Reductive amination of ethyl levulinate to pyrrolidones over AuPd nanoparticles at ambient hydrogen pressure
Muzzio, Michelle,Yu, Chao,Lin, Honghong,Yom, Typher,Boga, Dilek A.,Xi, Zheng,Li, Na,Yin, Zhouyang,Li, Junrui,Dunn, Joshua A.,Sun, Shouheng
, p. 1895 - 1899 (2019/04/29)
Herein, we describe a AuPd catalyst for selective and solventless conversion of ethyl levulinate (EL) and amines to pyrrolidones under ambient pressure. The optimized Au66Pd34 nanoparticle catalyst was stable and reusable over 10 runs. AuPd catalysis was extended to reductive amination of levulinic acid and 4-acetylbutyric acid, providing a green chemistry approach under milder conditions not only to pyrrolidones, but also to piperidines, both of which are important scaffolds in designing polymers, natural products and pharmaceuticals.
A Facile Direct Route to N-(Un)substituted Lactams by Cycloamination of Oxocarboxylic Acids without External Hydrogen
Li, Hu,Wu, Hongguo,Zhang, Heng,Su, Yaqiong,Yang, Song,Hensen, Emiel J. M.
, p. 3778 - 3784 (2019/08/07)
Lactams are privileged in bioactive natural products and pharmaceutical agents and widely featured in functional materials. This study presents a novel versatile approach to the direct synthesis of lactams from oxocarboxylic acids without catalyst or external hydrogen. The method involves the in situ release of formic acid from formamides induced by water to facilitate efficient cycloamination. Water also suppresses the formation of byproducts. This unconventional pathway is elucidated by a combination of model experiments and density functional theory calculations, whereby cyclic imines (5-methyl-3,4-dihydro-2-pyrrolone and its tautomeric structures) are found to be favorable intermediates toward lactam formation, in contrast to the conventional approach encompassing cascade reductive amination and cyclization. This sustainable and simple protocol is broadly applicable for the efficient production of various N-unsubstituted and N-substituted lactams.
Iron-Catalysed Switchable Synthesis of Pyrrolidines vs Pyrrolidinones by Reductive Amination of Levulinic Acid Derivatives via Hydrosilylation
Wei, Duo,Netkaew, Chakkrit,Darcel, Christophe
supporting information, p. 1781 - 1786 (2019/02/26)
A selective production of pyrrolidines vs pyrrolidinones via hydrosilylation of levulinic acid and levulinates by switching of the iron complex catalyst is presented herein. The reactions proceeded efficiently with various anilines and alkylamines under both visible light irradiation and thermal conditions with 43 examples in isolated yields up to 93%. Noticeably, under similar conditions, cyclic amines such as piperidines and azepanes were efficiently synthesized with yields up to 92%, by reaction of anilines with 1,5- or 1,6-keto acids, respectively. Similarly, N-arylinsolidoline compounds can be prepared from 2-formylbenzoic acid in 57–93% yields. (Figure presented.).
