- Electrochemical Aziridination of Internal Alkenes with Primary Amines
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An electrochemical approach to prepare aziridines via an oxidative coupling between alkenes and primary alkyl amines was realized. The reaction is carried out in an electrochemical flow reactor, leading to short reaction/residence times (5 min), high yields, and broad scope. At the cathode, hydrogen is generated, which can be used in a second reactor to reduce the aziridine yielding the corresponding hydroaminated product.Aziridines are useful synthetic building blocks, widely employed for the preparation of various nitrogen-containing derivatives. As the current methods require the use of prefunctionalized amines, the development of a synthetic strategy toward aziridines that can establish the union of alkenes and amines would be of great synthetic value. Herein, we report an electrochemical approach, which realizes this concept via an oxidative coupling between alkenes and primary alkylamines. The reaction is carried out in an electrochemical flow reactor leading to short reaction/residence times (5 min), high yields, and broad scope. At the cathode, hydrogen is generated, which can be used in a second reactor to reduce the aziridine, yielding the corresponding hydroaminated product. Mechanistic investigations and DFT calculations revealed that the alkene is first anodically oxidized and subsequently reacted with the amine coupling partner.The central tenet in modern synthetic methodology is to develop new methods only using widely available organic building blocks. As a direct consequence, new activation strategies are required to cajole the coupling partners to react and, subsequently, forge new and useful chemical bonds. Using electrochemical activation, our methodology enables for the first time the direct coupling between olefins and amines to yield aziridines. Aziridines display interesting pharmacological activity and serve as valuable synthetic intermediates to prepare diverse nitrogen-containing derivatives. Interestingly, the sole byproduct generated in this process is hydrogen, which can be subsequently used to reduce the aziridine into the corresponding hydroaminated product. Hence, this electrochemical methodology can be regarded as green and sustainable from the vantage point of upgrading simple and widely available commodity chemicals.
- Bartolomeu, Aloisio de A.,Dyga, Marco,Goo?en, Lukas J.,Laudadio, Gabriele,No?l, Timothy,O?eka, Maksim,de Bruin, Bas,de Oliveira, Kleber T.,van Leest, Nicolaas P.
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p. 255 - 266
(2021/01/19)
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- Direct Reductive Amination of Carbonyl Compounds with H2 Using Heterogeneous Catalysts in Continuous Flow as an Alternative to N-Alkylation with Alkyl Halides
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A general continuous-flow procedure for direct reductive amination of secondary and primary amines with aromatic and aliphatic aldehydes as well as ketones is reported. The use of hydrogen gas and commercially available Pt/C as a heterogeneous catalyst is a key. In addition to exhibiting an excellent functional group tolerance, this method allows the fast formation of C?N bonds without production of any hazardous chemical waste. Applications to the synthesis of key intermediates toward active pharmaceutical ingredients (Donepezil and Arformoterol/Tamsulosin) are also described. (Figure presented.).
- Laroche, Benjamin,Ishitani, Haruro,Kobayashi, Shū
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supporting information
p. 4699 - 4704
(2018/12/04)
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- Use of fenoterol and fenoterol analogues in the treatment of glioblastomas and astrocytomas
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This disclosure concerns the discovery of the use of fenoterol and (R,R)- and (R,S)-fenoterol analogs for the treatment of a tumor expressing a β2-adrenergic receptor, such as a primary brain tumor, including a glioblastoma or astrocytoma expressing a β2-adrenergic receptor. In one example, the method includes administering to a subject a therapeutically effective amount of fenoterol, a specific fenoterol analog or a combination thereof to reduce one or more symptoms associated with the tumor, thereby treating the tumor in the subject.
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Page/Page column 37; 55
(2016/12/07)
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- Design, synthesis and evaluation of dual pharmacology β2- adrenoceptor agonists and PDE4 inhibitors
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A novel series of formoterol-phthalazinone hybrids were synthesised and evaluated as dual pharmacology β2-adrenoceptor agonists and PDE4 inhibitors. Most of the hybrids displayed high β2-adrenoceptor agonist and moderate PDE4 inhibitory activities. The most potent compound, (R,R)-11c, exhibited agonist (EC50 = 1.05 nM, pEC50 = 9.0) and potent PDE4B2 inhibitory activities (IC50 = 0.092 μM).
- Huang, Ling,Shan, Wenjun,Zhou, Qi,Xie, Jiaxing,Lai, Kefang,Li, Xingshu
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supporting information
p. 249 - 253
(2014/01/17)
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- PROCESSES FOR PREPARING SUBSTANTIALLY PURE ARFORMOTEROL AND ITS INTERMEDIATES
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Provided herein are improved, convenient and industrially advantageous processes for the preparation of N-[2-hydroxy-5-[(1R)-1-hydroxy-2-[[(1R)-2-(4-methoxyphenyl)-1-methylethyl]amino]ethyl]phenyl]formamide (Arformoterol) or a pharmaceutically acceptable salt thereof, in high yield and purity. Provided further herein is an improved and industrially advantageous process for the preparation of a substantially enantiomerically pure arformoterol intermediate, (R)-4-methoxy-α-methyl-N-(phenylmethyl)benzeneethanamine.
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Page/Page column 14
(2012/01/13)
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- PREPARATION OF (R,R)-FENOTEROL AND (R,R)- OR (R,S)-FENOTEROL ANALOGUES AND THEIR USE IN TREATING CONGESTIVE HEART FAILURE
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This disclosure concerns the discovery of (R,R)- and (R,S)-fenoterol analogues which are highly effective at binding β2-adrenergic receptors. Exemplary chemical structures for these analogues are provided. Also provided are pharmaceutical compositions including the disclosed (R,R)-fenoterol and fenoterol analogues, and methods of using such compounds and compositions for the treatment of cardiac disorders such as congestive heart failure and pulmonary disorders such as asthma or chronic obstructive pulmonary disease.
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Page/Page column 40
(2008/06/13)
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- Comparative molecular field analysis of the binding of the stereoisomers of fenoterol and fenoterol derivatives to the β2 adrenergic receptor
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Stereoisomers of fenoterol and six fenoterol derivatives have been synthesized and their binding affinities for the β2 adrenergic receptor (Kiβ2-AR), the subtype selectivity relative to the β1-AR (Kiβ1-AR/K iβ2-AR) and their functional activities were determined. Of the 26 compounds synthesized in the study, submicromolar binding affinities were observed for (R,R)-fenoterol, the (R,R)-isomer of the p-methoxy, and (R,R)- and (R,S)-isomers of 1-naphthyl derivatives and all of these compounds were active at submicromolar concentrations in cardiomyocyte contractility tests. The Kiβ1-AR/K iβ2-AR ratios were >40 for (R,R)-fenoterol and the (R,R)-p-methoxy and (R,S)-1-naphthyl derivatives and 14 for the (R,R)-1-napthyl derivative. The binding data was analyzed using comparative molecular field analysis (CoMFA), and the resulting model indicated that the fenoterol derivatives interacted with two separate binding sites and one steric restricted site on the pseudo-receptor and that the chirality of the second stereogenic center affected Kiβ2 and subtype selectivity.
- Jozwiak, Krzysztof,Khalid, Chakir,Tanga, Mary J.,Berzetei-Gurske, Ilona,Jimenez, Lucita,Kozocas, Joseph A.,Woo, Anthony,Zhu, Weizhong,Xiao, Rui-Ping,Abernethy, Darrell R.,Wainer, Irving W.
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p. 2903 - 2915
(2008/02/07)
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- Large-scale synthesis of enantio- and diastereomerically pure (R,R)-formoterol
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(R,R)-Formoterol (1) is a long-acting, very potent β2-agonist, which is used as a bronchodilator in the therapy of asthma and chronic bronchitis. Highly convergent synthesis of enantio- and diastereomerically pure (R,R)-formoterol fumarate is achieved by a chromatography-free process with an overall yield of 44%. Asymmetric catalytic reduction of bromoketone 4 using as catalyst oxazaborolidine derived from (1R, 2S)-1-amino-2-indanol and resolution of chiral amine 3 are the origins of chirality in this process. Further enrichment of enantio- and diastereomeric purity is accomplished by crystallizations of the isolated intermediates throughout the process to give (R,R)-formoterol (1) as the pure stereoisomer (ee, de >99.5%).
- Hett, Robert,Fang, Qun K.,Gao, Yun,Wald, Stephen A.,Senanayake, Chris H.
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- Enantio- and diastereoselective synthesis of all four stereoisomers of formoterol
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Enantioselective syntheses of all four stereoisomers of formoterol are accomplished using asymmetric catalytic borane reductions with chiral oxazaborolidines as reducing agents.
- Hett, Robert,Fang, Qun Kevin,Gao, Yun,Hong, Yaping,Butler, Hal T.,Nie, Xiaoyi,Wald, Stephen A.
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p. 1125 - 1128
(2007/10/03)
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