86217-82-5Relevant academic research and scientific papers
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.
The Synthesis of Primary Amines through Reductive Amination Employing an Iron Catalyst
B?umler, Christoph,Bauer, Christof,Kempe, Rhett
, p. 3110 - 3114 (2020/06/01)
The reductive amination of ketones and aldehydes by ammonia is a highly attractive method for the synthesis of primary amines. The use of catalysts, especially reusable catalysts, based on earth-abundant metals is similarly appealing. Here, the iron-catalyzed synthesis of primary amines through reductive amination was realized. A broad scope and a very good tolerance of functional groups were observed. Ketones, including purely aliphatic ones, aryl–alkyl, dialkyl, and heterocyclic, as well as aldehydes could be converted smoothly into their corresponding primary amines. In addition, the amination of pharmaceuticals, bioactive compounds, and natural products was demonstrated. Many functional groups, such as hydroxy, methoxy, dioxol, sulfonyl, and boronate ester substituents, were tolerated. The catalyst is easy to handle, selective, and reusable and ammonia dissolved in water could be employed as the nitrogen source. The key is the use of a specific Fe complex for the catalyst synthesis and an N-doped SiC material as catalyst support.
Nano-Fe3O4@SiO2-SO3H: A magnetic, reusable solid-acid catalyst for solvent-free reduction of oximes to amines with the NaBH3CN/ZrCl4 system
Sadighnia, Leila,Zeynizadeh, Behzad,Karami, Shiva,Abdollahi, Mohammad
, p. 535 - 542 (2019/01/04)
In this study, the immobilization of sulfonic acid on silica-layered magnetite was carried out by the reaction of ClSO3H with silica-layered magnetite. The prepared magnetic nanoparticles of Fe3O4@SiO2-SO3H were then characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, vibrating sample magnetometry, and transmission electron microscopy. The sulfonated nanocomposite exhibited excellent catalytic activity and reusability in the reduction of various aldoximes and ketoximes with NaBH3CN in the presence of ZrCl4. All reactions were carried out under solvent-free conditions (r.t. or 75–80°C) within 3–70 min to afford amines in high to excellent yields.
Amine Transaminase from Exophiala Xenobiotica - Crystal Structure and Engineering of a Fold IV Transaminase that Naturally Converts Biaryl Ketones
Telzerow, Aline,Paris, Juraj,H?kansson, Maria,González-Sabín, Javier,Ríos-Lombardía, Nicolás,Schürmann, Martin,Gr?ger, Harald,Morís, Francisco,Kourist, Robert,Schwab, Helmut,Steiner, Kerstin
, p. 1140 - 1148 (2019/01/21)
Amine transaminases are frequently used for the production of chiral amines starting from prochiral ketones. These amines can be applied as active pharmaceutical ingredients or drug precursors. However, there are still limitations to the use of amine transaminases when it comes to bulky ketone substrates, such as biaryl ketones. Using data mining, an (R)-selective amine transaminase from Exophiala xenobiotica was identified which naturally converts biaryl ketone substrates to the corresponding amines with up to 85% conversion and excellent enantioselectivity (>99% ee). Its protein crystal structure was obtained with a resolution of 1.52 ?, which enabled us to explain this interesting substrate acceptance. Structure-guided protein engineering resulted in a quintuple variant with increased stability. Moreover, the amino acid exchange T273S increased the activity and broadened the substrate scope, enabling conversions of various biaryl ketones with up to >99%. A preparative biotransformation of 1-(4-(pyridin-3-yl)phenyl)ethenone at 75 mM (15 g/L) resulted in 96% of isolated yield of the respective amine.
Rh(III)-Catalyzed Coupling of N-Chloroimines with α-Diazo-α-phosphonoacetates for the Synthesis of 2 H-Isoindoles
Qi, Bing,Li, Lei,Wang, Qi,Zhang, Wenjing,Fang, Lili,Zhu, Jin
supporting information, p. 6860 - 6863 (2019/09/12)
We report herein the first use of N-chloroimines as effective synthons for directed C-H functionalization. Rh(III)-catalyzed coupling of N-chloroimines with α-diazo-α-phosphonoacetates allows for efficient dechlorinative/dephosphonative access to 2H-isoindoles. Further deesterification under Ni(II) catalysis enables the complete elimination of reactivity-assisting groups and full exposure of reactivity of C3 and N2 ring atoms for attaching structurally distinct appendages.
Combination of the Suzuki–Miyaura Cross-Coupling Reaction with Engineered Transaminases
Dawood, Ayad W. H.,Bassut, Jonathan,de Souza, Rodrigo O. M. A.,Bornscheuer, Uwe T.
supporting information, p. 16009 - 16013 (2018/10/15)
The combination of enzymatic and chemical reaction steps is one important area of research in organic synthesis, preferentially as cascade reactions in one-pot to improve total conversion and achieve high operational stability. Here, the combination of the Suzuki–Miyaura reaction is described to synthesize biaryl compounds followed by a transamination reaction. Careful optimization of the reaction conditions required for the chemo- and biocatalysis reaction enabled an efficient two-step-one-pot reaction yielding the final chiral amines with excellent optical purity (>99 % ee) in up to 84 % total conversion. Key to the success was the protein engineering of the amine transaminases from Asperguillus fumigatus (4CHI-TA) where single alanine mutations increased the conversion up to 2.3-fold. Finally, the transfer to a continuous flow system after immobilization of the best 4CHI-TA variant is demonstrated.
Pd-Catalyzed Suzuki coupling reactions of aryl halides containing basic nitrogen centers with arylboronic acids in water in the absence of added base
Li, Zhao,Gelbaum, Carol,Campbell, Zachary S.,Gould, Paul C.,Fisk, Jason S.,Holden, Bruce,Jaganathan, Arvind,Whiteker, Gregory T.,Pollet, Pamela,Liotta, Charles L.
supporting information, p. 15420 - 15432 (2017/12/15)
The Pd-catalyzed Suzuki coupling reactions of a series of aryl chlorides and aryl bromides containing basic nitrogen centers with arylboronic acids in water in the absence of added base are reported. The reactions proceed either partially or entirely under acidic conditions. After surveying twenty-two phosphorus ligands, high yields of products were obtained with aryl chlorides only when a bulky ligand, 2-(di-tert-butyl-phosphino)-1-phenyl-1H-pyrrole (cataCXiumPtB) was used. In contrast, aryl bromides produced high yields of products in the absence of both added base and added ligand. In order to explore the Suzuki coupling process entirely under acidic conditions, a series of reactions were conducted in buffered acidic media using several model substrates. 4-Chlorobenzylamine, in the presence of cataCXiumPtB, produced high yields of product at buffered pH 6.0; the yields dropped off precipitously at buffered pH 5.0 and lower. The fall-off in yield was attributed to the decomposition of the Pd-ligand complex due to the protonation of the ligand in the more acidic aqueous media. In contrast, in the absence of an added ligand, 4-amino-2-chloropyridine produced quantitative yields at buffered pH 3.5 and 4.5 while 4-amino-2-bromopyridine produced quantitative yields in a series of buffered media ranging from pH 4.5 to 1.5. These substrates are only partially protonated in acidic media and can behave as active Pd ligands in the Suzuki catalytic cycle.
METHODS FOR EXTERNAL BASE-FREE SUZUKI COUPLINGS
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Paragraph 0035-0036; 0037-0039, (2017/07/14)
The present disclosure describes a method of coupling a first aromatic compound to a second aromatic compound, the method comprising: (a) preparing a reaction mixture comprising the first aromatic compound, the second aromatic compound, a catalyst and water; the reaction mixture does not contain an external base, the reaction mixture having an initial pH of from 11 to 1; the catalyst having at least one group 10 atom; the first aromatic compound having a halogen, triflate or sulfonate substituent; the second aromatic compound having a boron-containing substituent; wherein, at least one of the first aromatic compound or the second aromatic compound includes one or more heteroatom; and (b) reacting the first aromatic compound and the second aromatic compound in the reaction mixture, the reaction mixture having a final pH following reaction of the first aromatic compound and the second aromatic compound.
Design and synthesis of calindol derivatives as potent and selective calcium sensing receptor agonists
Kiefer, Lionel,Beaumard, Floriane,Gorojankina, Tatiana,Faure, Hélène,Ruat, Martial,Dodd, Robert H.
, p. 554 - 569 (2016/02/09)
We report the first comprehensive structure-activity study of calindol (4, (R)-N-[(1H-indol-2-yl)methyl]-1-(1-naphthyl)ethanamine), a positive allosteric modulator, or calcimimetic, of the calcium sensing receptor (CaSR). While replacement of the naphthyl moiety of calindol by other aromatic groups (phenyl, biphenyl) was largely detrimental to calcimimetic activity, incorporation of substituents on the 4, 5 or 7 position of the indole portion of calindol was found to provide either equipotent derivatives compared to calindol (e.g., 4-phenyl, 4-hydroxy, 5-hydroxycalindol 44, 52, 53) or, in the case of 7-nitrocalindol (51), a 6-fold more active calcimimetic displaying an EC50 of 20 nM. Unlike calindol, the more active CaSR calcimimetics were shown not to act as antagonists of the closely related GPRC6A receptor, suggesting a more selective profile for these new analogues.
Aqueous Suzuki Coupling Reactions of Basic Nitrogen-Containing Substrates in the Absence of Added Base and Ligand: Observation of High Yields under Acidic Conditions
Li, Zhao,Gelbaum, Carol,Fisk, Jason S.,Holden, Bruce,Jaganathan, Arvind,Whiteker, Gregory T.,Pollet, Pamela,Liotta, Charles L.
, p. 8520 - 8529 (2016/09/28)
A series of aqueous heterogeneous Suzuki coupling reactions of substrates containing basic nitrogen centers with phenylboronic acid in the absence of added base and ligand is presented. High yields of products were obtained by employing aryl bromides containing aliphatic 1°, 2°, and 3° amine substituents, and good to high yields were obtained by employing a variety of substituted bromopyridines. In the former series, the pH of the aqueous phase changed from basic to acidic during the course of the reaction, while in the latter series the aqueous phase was on the acidic side of the pH scale throughout the entire course of reaction. A mechanistic interpretation for these observations, which generally preserves the oxo palladium catalytic cycle widely accepted in the literature, is presented.
