- Rhodium(iii)-catalyzed asymmetric [4+1] spiroannulations of: O -pivaloyl oximes with α-diazo compounds
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Chiral RhIII catalysts can catalyze the asymmetric [4+1] spiroannulation of O-pivaloyl oximes with α-diazo homophthalimides under redox-neutral and acid/base-neutral conditions, leading to formation of chiral spirocyclic imines as a result of C-H activation and N-O cleavage. The reaction proceeded with high efficiency and features broad substrate scope, mild reaction conditions, and high to excellent enantioselectivities. This journal is
- Chang, Junbiao,Deng, Wei-Qiao,Kong, Lingheng,Li, Xingwei,Liu, Bingxian,Sun, Lincong,Wang, Fen,Zhao, Yanlian
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supporting information
p. 8268 - 8271
(2021/08/25)
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- Access to Cyanoimines Enabled by Dual Photoredox/Copper-Catalyzed Cyanation of O-Acyl Oximes
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An efficient strategy for the synthesis of pharmaceutically important and synthetically useful cyanoimines, as well as cyanamides, has been described. This strategy is enabled by dual photoredox/copper-catalyzed cyanation of O-acyl oximes or O-acyl hydroxamides. This state of the art protocol for cyanoimines and cyanamides features readily available starting materials, mild reaction conditions, good functional group tolerance, and operational simplicity. The resultant cyanoimines can be transformed into structurally diverse and functionally important N-containing heterocycles.
- Wei, Ziyan,Yu, Shouyun,Zhang, Ai Hua,Zhang, Hao
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supporting information
p. 7315 - 7320
(2020/10/02)
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- Redox-Neutral Access to Isoquinolinones via Rhodium(III)-Catalyzed Annulations of O-Pivaloyl Oximes with Ketenes
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A mild and redox-neutral [4 + 2] annulation of O-pivaloyl oximes with ketenes has been realized for synthesis of quaternary-carbon-stereocenter-containing (QCSC) isoquinolinones, where the N-OPiv not only acts as an oxidizing group but also offers coordination saturation to inhibit protonolysis. The reaction mechanism has been studied by DFT calculations.
- Yang, Xifa,Liu, Song,Yu, Songjie,Kong, Lingheng,Lan, Yu,Li, Xingwei
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supporting information
p. 2698 - 2701
(2018/05/22)
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- Scope and mechanism of a true organocatalytic beckmann rearrangement with a boronic acid/perfluoropinacol system under ambient conditions
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Catalytic activation of hydroxyl functionalities is of great interest for the production of pharmaceuticals and commodity chemicals. Here, 2-alkoxycarbonyl- and 2-phenoxycarbonyl-phenylboronic acid were identified as efficient catalysts for the direct and chemoselective activation of oxime N-OH bonds in the Beckmann rearrangement. This classical organic reaction provides a unique approach to prepare functionalized amide products that may be difficult to access using traditional amide coupling between carboxylic acids and amines. Using only 5 mol % of boronic acid catalyst and perfluoropinacol as an additive in a polar solvent mixture, the operationally simple protocol features mild conditions, a broad substrate scope, and a high functional group tolerance. A wide variety of diaryl, aryl-alkyl, heteroaryl-alkyl, and dialkyl oximes react under ambient conditions to afford high yields of amide products. Free alcohols, amides, carboxyesters, and many other functionalities are compatible with the reaction conditions. Investigations of the catalytic cycle revealed a novel boron-induced oxime transesterification providing an acyl oxime intermediate involved in a fully catalytic nonself-propagating Beckmann rearrangement mechanism. The acyl oxime intermediate was prepared independently and was subjected to the reaction conditions. It was found to be self-sufficient; it reacts rapidly, unimolecularly without the need for free oxime. A series of control experiments and 18O labeling studies support a true catalytic pathway involving an ionic transition structure with an active and essential role for the boronyl moiety in both steps of transesterification and rearrangement. According to 11B NMR spectroscopic studies, the additive perfluoropinacol provides a transient, electrophilic boronic ester that is thought to serve as an internal Lewis acid to activate the ortho-carboxyester and accelerate the initial, rate-limiting step of transesterification between the precatalyst and the oxime substrate.
- Mo, Xiaobin,Morgan, Timothy D. R.,Ang, Hwee Ting,Hall, Dennis G.
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supporting information
p. 5264 - 5271
(2018/04/24)
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- Copper-catalyzed synthesis of thiazol-2-yl ethers from oxime acetates and xanthates under redox-neutral conditions
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A novel copper-catalyzed annulation of oxime acetates and xanthates for the synthesis of thiazol-2-yl ethers with remarkable regioselectivity has been developed. Various oxime acetates, whether derived from aryl ketones or alkyl ketones, or natural product cores are suitable for this conversion. Unique dihydrothiazoles were also obtained when both reaction sites were methine. Mechanistic studies indicated that imino copper(iii) intermediates were involved. In addition, this protocol proceeded under redox-neutral conditions and did not require additives or ligands.
- Zhu, Zhongzhi,Tang, Xiaodong,Cen, Jinghe,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 3767 - 3770
(2018/04/17)
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- Iron-Catalyzed Synthesis of 2H-Imidazoles from Oxime Acetates and Vinyl Azides under Redox-Neutral Conditions
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A novel and versatile method for the synthesis of 2H-imidazoles via iron-catalyzed [3 + 2] annulation from readily available oxime acetates with vinyl azides has been developed. This denitrogenative process involved N-O/N-N bond cleavages and two C-N bond formations to furnish 2,4-substituted 2H-imidazoles. This protocol was performed under mild reaction conditions and needed no additives or ligands. Furthermore, this is a green reaction involving oxime acetate as internal oxidant, acetic acid, and nitrogen as byproducts.
- Zhu, Zhongzhi,Tang, Xiaodong,Li, Jianxiao,Li, Xianwei,Wu, Wanqing,Deng, Guohua,Jiang, Huanfeng
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supporting information
p. 1370 - 1373
(2017/03/23)
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- Easy Access to 1-Amino and 1-Carbon Substituted Isoquinolines via Cobalt-Catalyzed C - H/N - O Bond Activation
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A green atom-economical method for the synthesis of highly functionalized 1-amino and 1-carbon substituted isoquinolines from the reaction of N′-hydroxybenzimidamides and aryl ketoximes, respectively, with alkynes via pentamethylcyclopentadienylcobalt(III)-catalyzed C - H/N - O bond activation is described. The external oxidant-free annulation reaction uses the =NOH moiety in N′-hydroxybenzimidamides or N-aromatic ketone oximes as the directing group and internal oxidant. This first row transition metal-catalyzed annulation serves as an efficient alternative for the synthesis of isoquinolines, as water is the only by-product and expensive noble metals such as rhodium(III), iridium(III), palladium(II), and ruthenium(II) are not required. The reaction proceeds via C - H activation, alkyne insertion, reductive elimination, and N - O activation.
- Muralirajan, Krishnamoorthy,Kuppusamy, Ramajayam,Prakash, Sekar,Cheng, Chien-Hong
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supporting information
p. 774 - 783
(2016/03/09)
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- N-(HETERO)ARYL-PYRROLIDINE DERIVATIVES OF PYRAZOL-4-YL-PYRROLO[2,3-d]PYRIMIDINES AND PYRROL-3-YL-PYRROLO[2,3-d]PYRIMIDINES AS JANUS KINASE INHIBITORS
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The present invention relates to N-(hetero)aryl-pyrrolidine derivatives of Formula I: which are JAK inhibitors, such as selective JAK1 inhibitors, useful in the treatment of JAK-associated diseases including, for example, inflammatory and autoimmune disorders, as well as cancer.
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Page/Page column 74
(2010/12/29)
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- FARNESOID X RECEPTOR AGONISTS
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The present invention relates to famesoid X receptors (FXR, NR1 H4) FXR is a member of the nuclear receptor class of ligand-activated transcription factors More particularly, the present invention relates to compounds useful as agonists for FXR, pharmaceu
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Page/Page column 90
(2009/01/23)
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- HETEROTRICYCLIC COMPOUNDS FOR USE AS HCV INHIBITORS
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The present invention comprises tetrazoloquinine-compounds that are inhibitors of HCV. Compositions comprising the compounds in combination with a pharmaceutically acceptable carrier are also disclosed, as are methods of using the compounds and compositions to inhibit HCV infection of a cell, particular in the form of treating HCV infection in a mammal.
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Page/Page column 29
(2008/06/13)
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- Thienotriazines
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Fused tetracyclic compounds containing two thiophene rings, one pyridine ring and a triazine ring and which are useful as antiallergic agents are described herein. The compounds are prepared by the reaction of an appropriate substituted aminocarboxamine with sodium nitrite in an acid such as acetic acid.
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- Tetrazolothienopyridines
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(1H-Tetrazol-5-yl)tetrazolo[1,5-a]thienopyridines and related compounds which are useful as antiallergic agents are described herein. The compounds are prepared by the reaction of an appropriate halocyano-quinoline with ammonium chloride and an azide such as sodium azide in an inert solvent such as dimethylformamide.
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- (Tetrazolyl) thienopyridinones
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(1H-Tetrazol-5-yl)thienopyridinones and related compounds which are useful as antiallergic agents are described herein. The compounds are prepared by the reaction of an appropriate cyanoketone with ammonium chloride and an azide such as sodium azide in an inert solvent such as dimethylformamide.
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