- Catalytic Asymmetric Synthesis of Morpholines. Using Mechanistic Insights to Realize the Enantioselective Synthesis of Piperazines
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An efficient and practical catalytic approach for the enantioselective synthesis of 3-substituted morpholines through a tandem sequential one-pot reaction employing both hydroamination and asymmetric transfer hydrogenation reactions is described. Starting from ether-containing aminoalkyne substrates, a commercially available bis(amidate)bis(amido)Ti catalyst is utilized to yield a cyclic imine that is subsequently reduced using the Noyori-Ikariya catalyst, RuCl [(S,S)-Ts-DPEN] (η6-p-cymene), to afford chiral 3-substituted morpholines in good yield and enantiomeric excesses of >95%. A wide range of functional groups is tolerated. Substrate scope investigations suggest that hydrogen-bonding interactions between the oxygen in the backbone of the ether-containing substrate and the [(S,S)-Ts-DPEN] ligand of the Ru catalyst are crucial for obtaining high ee's. This insight led to a mechanistic proposal that predicts the observed absolute stereochemistry. Most importantly, this mechanistic insight allowed for the extension of this strategy to include N as an alternative hydrogen bond acceptor that could be incorporated into the substrate. Thus, the catalytic, enantioselective synthesis of 3-substituted piperazines is also demonstrated.
- Lau, Ying Yin,Zhai, Huimin,Schafer, Laurel L.
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p. 8696 - 8709
(2016/10/14)
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- Diastereoselective synthesis of tetrasubstituted propargylamines via hydroamination and metalation of 1-alkynes and their enantioselective conversion to trisubstituted chiral allenes
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Reaction of cyclic secondary amines with 1-alkynes and copper(I) chloride at 110-120 °C gives the corresponding alkynylcopper complex, which adds to the iminium ion intermediate formed in situ by hydroamination of 1-alkynes to give the corresponding propargylamine derivatives in up to 94% yield and 99% regioselectivity. The diastereomerically pure chiral propargylamines were obtained in 23-89% yield using optically active 2-benzyl morpholine and N-methyl camphanyl piperazine. These chiral propargylamines are readily converted to the corresponding trisubstitued chiral allenes in 71-89% yields with up to 99% ee upon reaction with ZnBr2 at 120 °C. The results are discussed considering mechanisms involving diastereoselective addition of alkynylcopper complex formed in situ to iminium ions formed in situ regioselectively to produce the corresponding propargylamines, which in turn give the chiral allenes with very high enantioselectivity via an intramolecular 1,5-hydrogen shift in the presence of zinc bromide.
- Periasamy, Mariappan,Reddy, Polimera Obula,Satyanarayana, Iddum,Mohan, Lakavathu,Edukondalu, Athukuri
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p. 987 - 999
(2016/02/18)
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- Combined Imine Reductase and Amine Oxidase Catalyzed Deracemization of Nitrogen Heterocycles
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A novel amine oxidase (AO)/imine reductase (IRED) system was developed for the deracemization of racemic amines. By combining (R)-6-hydroxy-d-nicotine oxidase (6-HDNO) with an (R)-IRED, a panel of racemic 2-substituted piperidines and pyrrolidines were deracemized to yield the (S)-amines in high yields and enantiomeric excess values. Other N-heterocycles were deracemized with monoamine oxidase (MAO-N) or 6-HDNO in combination with ammonia borane, which allowed comparison of the two enzyme deracemization approaches with that involving a chemical reducing agent.
- Heath, Rachel S.,Pontini, Marta,Hussain, Shahed,Turner, Nicholas J.
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p. 117 - 120
(2016/01/26)
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- Stereoelectronic basis for the kinetic resolution of n-heterocycles with chiral acylating reagents
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The kinetic resolution of N-heterocycles with chiral acylating agents reveals a previously unrecognized stereoelectronic effect in amine acylation. Combined with a new achiral hydroxamate, this effect makes possible the resolution of various N-heterocycles by using easily prepared reagents. A transition-state model to rationalize the stereochemical outcome of this kinetic resolution is also proposed.
- Hsieh, Sheng-Ying,Wanner, Benedikt,Wheeler, Philip,Beauchemin, Andre M.,Rovis, Tomislav,Bode, Jeffrey W.
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supporting information
p. 7228 - 7231
(2014/06/23)
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- Amine-promoted asymmetric (4+2) annulations for the enantioselective synthesis of tetrahydropyridines: A traceless and recoverable auxiliary strategy
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Gone, without a trace: The in situ reaction of 2-(acetoxymethyl)buta-2,3- dienoate and a secondary amine produces a 2-methylene-3-oxobutanoate equivalent that can be used in asymmetric [4+2] annulations with N-tosylimines to provide tetrahydropyridines in
- Hu, Pengfei,Hu, Jian,Jiao, Jiajun,Tong, Xiaofeng
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p. 5319 - 5322
(2013/06/05)
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- KINETIC RESOLUTION OF CHIRAL AMINES
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The present invention refers to a method for the kinetic resolution of a chiral primary or secondary amine by treating the amine with a chiral, hydroxamic acid derived reagent of the formula (I). These chiral reagents are particularly useful for the kinetic resolution of cyclic amines and may be generated in situ in the presence of an N-heterocyclic carbene, thus allowing for a catalytic reaction.
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Page/Page column 128
(2013/03/26)
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- Expanded substrate scope and catalyst optimization for the catalytic kinetic resolution of N-heterocycles
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The scope, reactivity, and selectivity of the chiral hydroxamic acid-catalyzed kinetic resolution of chiral amines are improved by a new catalyst structure and a more environmentally friendly reaction protocol. In addition to increasing selectivity across all substrates, these conditions make possible the resolution of N-heterocycles containing lactams or other basic functional groups that can inhibit the catalyst.
- Hsieh, Sheng-Ying,Binanzer, Michael,Kreituss, Imants,Bode, Jeffrey W.
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supporting information
p. 8892 - 8894
(2012/11/07)
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- Catalytic kinetic resolution of cyclic secondary amines
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The catalytic resolution of racemic cyclic amines has been achieved by an enantioselective amidation reaction featuring an achiral N-heterocyclic carbene catalyst and a new chiral hydroxamic acid cocatalyst working in concert. The reactions proceed at room temperature, do not generate nonvolatile byproducts, and provide enantioenriched amines by aqueous extraction.
- Binanzer, Michael,Hsieh, Sheng-Ying,Bode, Jeffrey W.
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supporting information; experimental part
p. 19698 - 19701
(2012/01/13)
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- Synthesis of enantiopure 3-substituted morpholines
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Enantiopure 3-substituted morpholines were assembled through ring-opening of a N-2-benzothiazolesulfonyl (Bts) activated aziridine with organocuprates followed by a ring annulation reaction with a vinylsulfonium salt under microwave conditions. Deprotecti
- Bornholdt, Jan,Felding, Jakob,Kristensen, Jesper Langgaard
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supporting information; experimental part
p. 7454 - 7457
(2011/01/04)
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- 4-(1,3-Thiazol-2-yl)morpholine derivatives as inhibitors of phosphoinositide 3-kinase
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4-(1,3-Thiazol-2-yl)morpholine derivatives have been identified as potent and selective inhibitors of phosphoinositide 3-kinase. The SAR data of selected examples are presented and the in vivo profiling of compound 18 is shown to demonstrate the utility of this class of compounds in xenograft models of tumor growth.
- Alexander, Rikki,Balasundaram, Ahrani,Batchelor, Mark,Brookings, Daniel,Crepy, Karen,Crabbe, Tom,Deltent, Marie-France,Driessens, Frank,Gill, Andrew,Harris, Sue,Hutchinson, Gillian,Kulisa, Claire,Merriman, Mark,Mistry, Prakash,Parton, Ted,Turner, James,Whitcombe, Ian,Wright, Sara
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scheme or table
p. 4316 - 4320
(2009/04/06)
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- FUSED THIAZOLE DERIVATIVES AS KINASE INHIBITORS
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A series of 5,6-dihydro-l,3-benzothiazol-7(4H)-one derivatives, and analogues thereof, which are substituted in the 2-position by an optionally substituted morpholin-4-yl moiety, being selective inhibitors of PD kinase enzymes, are accordingly of b.enefit in medicine, for example in the treatment of inflammatory, autoimmune, cardiovascular, neurodegenerative, metabolic, oncological, nociceptive or ophthalmic conditions.
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Page/Page column 51-52
(2008/06/13)
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- 4-OXO-4,7-DIHYDROTHIENO[2,3-b]PYRIDINE-5-CARBOXAMIDES AS ANTIVIRAL AGENTS
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The present invention provides a compound of a formula (I) as described herein, which are useful as antiviral agents, in particular, as agents againts viruses of the herpes family.
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- A synthesis of (S)-3-(phenylmethyl)morpholine from (S)-phenylalanol
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A preparation of (S)-3-(phenylmethyl)morpholine from (S)-phenylated is described.
- Shawe, Thomas T.,Koenig Jr., George J.,Ross, Andrew A.
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p. 1777 - 1782
(2007/10/03)
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