88196-70-7Relevant academic research and scientific papers
Catalytic asymmetric oxidative carbonylation-induced kinetic resolution of sterically hindered benzylamines to chiral isoindolinones
Mu, Qiu-Qi,Nie, Yi-Xue,Li, Hang,Bai, Xing-Feng,Liu, Xue-Wei,Xu, Zheng,Xu, Li-Wen
supporting information, p. 1778 - 1781 (2021/02/27)
A highly enantioselective kinetic resolution of sterically hindered benzylamines has been achieved for the first time through transition-metal-catalyzed oxidative carbonylation, in which the new KR strategy offered a new approach to afford chiral isoindolinones (er up to 97?:?3) and the origin of chemoselectivity and stereoselectivity was confirmed by density functional theory (DFT) calculations.
Oxidation Under Reductive Conditions: From Benzylic Ethers to Acetals with Perfect Atom-Economy by Titanocene(III) Catalysis
Funk, Pierre,Richrath, Ruben B.,Bohle, Fabian,Grimme, Stefan,Gans?uer, Andreas
, p. 5482 - 5488 (2021/02/03)
Described here is a titanocene-catalyzed reaction for the synthesis of acetals and hemiaminals from benzylic ethers and benzylic amines, respectively, with pendant epoxides. The reaction proceeds by catalysis in single-electron steps. The oxidative addition comprises an epoxide opening. An H-atom transfer, to generate a benzylic radical, serves as a radical translocation step, and an organometallic oxygen rebound as a reductive elimination. The reaction mechanism was studied by high-level dispersion corrected hybrid functional DFT with implicit solvation. The low-energy conformational space was searched by the efficient CREST program. The stereoselectivity was deduced from the lowest lying benzylic radical structures and their conformations are controlled by hyperconjugative interactions and steric interactions between the titanocene catalyst and the aryl groups of the substrate. An interesting mechanistic aspect is that the oxidation of the benzylic center occurs under reducing conditions.
Ultra-small cobalt nanoparticles from molecularly-defined Co-salen complexes for catalytic synthesis of amines
Beller, Matthias,Chandrashekhar, Vishwas G.,Gawande, Manoj B.,Jagadeesh, Rajenahally V.,Kalevaru, Narayana V.,Kamer, Paul C. J.,Senthamarai, Thirusangumurugan,Zbo?il, Radek
, p. 2973 - 2981 (2020/03/27)
We report the synthesis of in situ generated cobalt nanoparticles from molecularly defined complexes as efficient and selective catalysts for reductive amination reactions. In the presence of ammonia and hydrogen, cobalt-salen complexes such as cobalt(ii)-N,N′-bis(salicylidene)-1,2-phenylenediamine produce ultra-small (2-4 nm) cobalt-nanoparticles embedded in a carbon-nitrogen framework. The resulting materials constitute stable, reusable and magnetically separable catalysts, which enable the synthesis of linear and branched benzylic, heterocyclic and aliphatic primary amines from carbonyl compounds and ammonia. The isolated nanoparticles also represent excellent catalysts for the synthesis of primary, secondary as well as tertiary amines including biologically relevant N-methyl amines.
General and selective synthesis of primary amines using Ni-based homogeneous catalysts
Beller, Matthias,Chandrashekhar, Vishwas G.,Jagadeesh, Rajenahally V.,Jiao, Haijun,Murugesan, Kathiravan,Wei, Zhihong
, p. 4332 - 4339 (2020/05/18)
The development of base metal catalysts for industrially relevant amination and hydrogenation reactions by applying abundant and atom economical reagents continues to be important for the cost-effective and sustainable synthesis of amines which represent highly essential chemicals. In particular, the synthesis of primary amines is of central importance because these compounds serve as key precursors and central intermediates to produce value-added fine and bulk chemicals as well as pharmaceuticals, agrochemicals and materials. Here we report a Ni-triphos complex as the first Ni-based homogeneous catalyst for both reductive amination of carbonyl compounds with ammonia and hydrogenation of nitroarenes to prepare all kinds of primary amines. Remarkably, this Ni-complex enabled the synthesis of functionalized and structurally diverse benzylic, heterocyclic and aliphatic linear and branched primary amines as well as aromatic primary amines starting from inexpensive and easily accessible carbonyl compounds (aldehydes and ketones) and nitroarenes using ammonia and molecular hydrogen. This Ni-catalyzed reductive amination methodology has been applied for the amination of more complex pharmaceuticals and steroid derivatives. Detailed DFT computations have been performed for the Ni-triphos based reductive amination reaction, and they revealed that the overall reaction has an inner-sphere mechanism with H2metathesis as the rate-determining step.
Design, synthesis and antifungal activity of threoninamide carbamate derivatives via pharmacophore model
Dong, Wei-Li,Du, Xiu-Jiang,Liu, Xing-Hai,Peng, Xing-Jie,Zhao, Rui-Qi,Zhao, Wei-Guang
, p. 682 - 691 (2020/03/19)
Thirty-six novel threoninamide carbamate derivatives were designed and synthesised using active fragment-based pharmacophore model. Antifungal activities of these compounds were tested against Oomycete fungi Phytophthora capsici in vitro and in vivo. Interestingly, compound I-1, I-2, I-3, I-6 and I-7 exhibited moderate control effect (>50%) against Pseudoperonospora cubensis in greenhouse at 6.25 μg/mL, which is better than that of control. Meanwhile most of these compounds exhibited significant inhibitory against P. capsici. The other nine fungi were also tested. More importantly, some compounds exhibited remarkably high activities against Sclerotinia sclerotiorum, P. piricola and R. solan in vitro with EC50 values of 3.74–9.76 μg/mL. It is possible that the model is reliabile and this method can be used to discover lead compounds for the development of fungicides.
Rh(III)-catalyzed synthesis of isoquinolines using the N-Cl bond of N-chloroimines as an internal oxidant
Chu, Benfa,Fang, Lili,Guo, Shan,Qi, Bing,Shi, Pengfei,Wang, Qi,Zhu, Jin
supporting information, (2020/03/10)
The Rh(III)-catalyzed coupling of N-chloroimines with alkynes for the efficient synthesis of isoquinolines is reported. This represents the first use of the N-Cl bond of N-chloroimines as an internal oxidant for construction of the isoquinoline skeleton. The synthesis features atom and step economy, a green solvent (EtOH), mild reaction conditions, and a broad substrate scope.
Chiral benzimidazole derived bis-phenyl triazoles as chiroptical sensors for iodide and chiral amines
John, Marina E.,Karnik, Anil V.
supporting information, p. 2844 - 2853 (2020/05/25)
A series of chiral 2-hydroxy ethyl/benzyl benzimidazole based aryl triazole tweezers have been prepared using click chemistry in high yields. Chiral pool strategy has been used to obtain the benzimidazole-based tweezers in very high enantiomerically enriched form. The aryl triazole tweezers, S-(?)-5a and S-(+)-8a displayed a high degree of selectivity for iodide anion over other anions, including other halides. The aryl triazole tweezers, S-(?)-5a and S-(+)-8a display significant enantio-discrimination for chiral amines. The chiral recognition studies were carried out using UV and circular dichroism (CD) spectroscopy. NMR analysis has been used for establishing the sites for ligation of the iodide anion.
Method for synthesizing chiral amine compound
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Paragraph 0064; 0071-0073; 0120-0122, (2019/10/01)
The present invention provides a method for synthesizing a chiral amine compound. The method comprises the following steps: (1) reacting a compound of formula I with t-butylsulfonamide in the presenceof a catalyst to obtain a compound having a structure represented by formula II; 2) reacting the compound of the formula II in a hydrogen atmosphere in the presence of an iridium catalyst and a ligand to obtain a compound of formula III; and (3) carrying out a t-butylsulfonyl group removal reaction on the compound of the formula III to obtain the chiral amine compound. The method constructs the structure of sulfonamide by a keto carbonylgroup, and synthesizes the chiral amine compound with the aralkylamine structure by an asymmetric catalytic hydrogenation reaction of the sulfonamide structure, the ee value is generally 80% or above, the highest ee value is 99% or above, the yield of each step reaction can reach 90% or above, and the total yield is high.
Nickel-Catalyzed Asymmetric Hydrogenation of N-Sulfonyl Imines
Li, Bowen,Chen, Jianzhong,Zhang, Zhenfeng,Gridnev, Ilya D.,Zhang, Wanbin
, p. 7329 - 7334 (2019/05/01)
An efficient nickel-catalyzed asymmetric hydrogenation of N-tBu-sulfonyl imines was developed with excellent yields and enantioselectivities using (R,R)-QuinoxP* as a chiral ligand. The use of a much lower catalyst loading (0.0095 mol %, S/C=10500) represents the highest catalytic activity for the Ni-catalyzed asymmetric hydrogenations reported so far. Mechanistic studies suggest that a coordination equilibrium exists between the nickel salt and its complex, and that excess nickel salt promotes the formation of the active Ni-complex, and therefore improved the efficiency of the hydrogenation. The catalytic cycle was also investigated by calculations to determine the origin of the enantioselectivity. An extensive network of numerous weak attractive interactions was found to exist between the catalyst and substrate in the transition state and may also contribute to the high catalytic activity.
Deracemization of sec-alcohols through sequential application of C. Albicans and Ketoreductases
Nasário, Fábio D.,Moran, Paulo J.S.,Rodrigues, José Augusto R.
, p. 772 - 779 (2019/08/26)
A biocatalytic cascade process was developed using immobilized cells of the wild type yeast Candida albicans CCT 0776 in calcium alginate beads and a commercially available ketoreductase. The aim was to promote deracemization by stereoinversion of (±)-1-arylethanols in high substrate concentration (above 100 mmol L-1) to prepare the (R)-enantiomers of the alcohols (90-99percent), with a high enantiomeric excess (83-99percent) after 2 to 19 h. The (R)-1-(3-methoxyphenyl)ethanol, with 70percent yield and 91percent ee, obtained after 5 h was used to prepare (S)-1-(3-methoxyphenyl)-ethylamine with 60percent yield and 91percent ee after two steps, a key intermediate in the synthesis of (S)-rivastigmine.
