- Highly Robust Iron Catalyst System for Intramolecular C(sp3)?H Amidation Leading to γ-Lactams
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Disclosed here is the use of an iron catalyst system for an intramolecular C?H amidation toward γ-lactam synthesis from dioxazolone precursors. (Phthalocyanine)FeIIICl was found to catalyze this cyclization with extremely high turnover numbers of up to 47 000 under mild and aerobic conditions. On the basis of experimental and computational mechanistic studies, the reaction is suggested to proceed by a stepwise radical pathway involving fast hydrogen atom abstraction followed by radical rebound. A plausible origin for the high turnover numbers along with air-compatibility is also rationalized.
- Kweon, Jeonguk,Chang, Sukbok
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supporting information
p. 2909 - 2914
(2020/12/11)
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- Tuning Triplet Energy Transfer of Hydroxamates as the Nitrene Precursor for Intramolecular C(sp3)-H Amidation
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Reported herein is the design of a photosensitization strategy to generate triplet nitrenes and its applicability for the intramolecular C-H amidation reactions. Substrate optimization by tuning physical organic parameters according to the proposed energy transfer pathway led us to identify hydroxamates as a convenient nitrene precursor. While more classical nitrene sources, representatively organic azides, were ineffective under the current photosensitization conditions, hydroxamates, which are readily available from alcohols or carboxylic acids, are highly efficient in accessing synthetically valuable 2-oxazolidinones and γ-lactams by visible light. Mechanism studies supported our working hypothesis that the energy transfer path is mainly operative.
- Chang, Sukbok,Jung, Hoimin,Keum, Hyeyun,Kweon, Jeonguk
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supporting information
p. 5811 - 5818
(2020/04/10)
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- COMPOUND HAVING BET INHIBITORY ACTIVITY AND PREPARATION METHOD AND USE THEREFOR
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The invention relates to the field of pharmaceutical chemistry. Specifically, the present invention relates to a series of BET (bromodomain and extra-terminal domain) inhibitors having a novel structure, particularly inhibitors targeting BRD4 (Bromodomain-containing protein 4), and a preparation method and use therefor. The structure thereof is shown in the following general formula (I). Said compounds or a stereoisomer, racemate, geometric isomer, tautomer, prodrug, hydrate, solvate, or crystal form thereof, or a pharmaceutically acceptable salt thereof, and the pharmaceutical compsosition thereof can be used for the treatment and/or prevention of related diseases mediated by bromodomain proteins.
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Paragraph 0157; 0160-0161
(2020/12/22)
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- Harnessing Secondary Coordination Sphere Interactions That Enable the Selective Amidation of Benzylic C-H Bonds
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Engineering site-selectivity is highly desirable especially in C-H functionalization reactions. We report a new catalyst platform that is highly selective for the amidation of benzylic C-H bonds controlled by π-πinteractions in the secondary coordination sphere. Mechanistic understanding of the previously developed iridium catalysts that showed poor regioselectivity gave rise to the recognition that the π-cloud of an aromatic fragment on the substrate can act as a formal directing group through an attractive noncovalent interaction with the bidentate ligand of the catalyst. On the basis of this mechanism-driven strategy, we developed a cationic (ν5-C5H5)Ru(II) catalyst with a neutral polypyridyl ligand to obtain record-setting benzylic selectivity in an intramolecular C-H lactamization in the presence of tertiary C-H bonds at the same distance. Experimental and computational techniques were integrated to identify the origin of this unprecedented benzylic selectivity, and robust linear free energy relationship between solvent polarity index and the measured site-selectivity was found to clearly corroborate that the solvophobic effect drives the selectivity. Generality of the reaction scope and applicability toward versatile γ-lactam synthesis were demonstrated.
- Jung, Hoimin,Schrader, Malte,Kim, Dongwook,Baik, Mu-Hyun,Park, Yoonsu,Chang, Sukbok
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supporting information
p. 15356 - 15366
(2019/10/22)
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- Method for synthesizing lactam derivative without catalyst
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The invention discloses a simple synthesis method for a lactam derivative. The method comprises the step that with formamide as an amine source and a hydrogen donor (hydrolyzed to produce formic acid)and keto acid as raw materials, the lactam derivative is easily synthesized through a cycloamination reaction without a solvent or a catalyst. Compared with previous reports, the time required for the reaction is greatly shortened, the selectivity is remarkably improved, the conversion rate of the keto acid derivative is 99%, and the yield of the lactam derivative can reach 70-94%.
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Paragraph 0022-0025
(2019/07/10)
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- Synthetic Utility of N-Benzoyloxyamides as an Alternative Precursor of Acylnitrenoids for γ-Lactam Formation
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Described herein is the development of a new entry of acylnitrenoid precursors for γ-lactam synthesis via an intramolecular C-H amidation reaction. Upon Ir catalysis, N-benzoyloxyamides serve as efficient substrates to afford 5-membered amides. Mechanistic studies revealed that the generation of a putative Ir-carbonylnitrenoid via N-O bond cleavage is facilitated by the chelation of countercations. This protocol offers a convenient and step-economic route to γ-lactams starting from the corresponding carboxylic acids.
- Huh, Soohee,Hong, Seung Youn,Chang, Sukbok
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supporting information
p. 2808 - 2812
(2019/04/17)
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- A Facile Direct Route to N-(Un)substituted Lactams by Cycloamination of Oxocarboxylic Acids without External Hydrogen
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Lactams are privileged in bioactive natural products and pharmaceutical agents and widely featured in functional materials. This study presents a novel versatile approach to the direct synthesis of lactams from oxocarboxylic acids without catalyst or external hydrogen. The method involves the in situ release of formic acid from formamides induced by water to facilitate efficient cycloamination. Water also suppresses the formation of byproducts. This unconventional pathway is elucidated by a combination of model experiments and density functional theory calculations, whereby cyclic imines (5-methyl-3,4-dihydro-2-pyrrolone and its tautomeric structures) are found to be favorable intermediates toward lactam formation, in contrast to the conventional approach encompassing cascade reductive amination and cyclization. This sustainable and simple protocol is broadly applicable for the efficient production of various N-unsubstituted and N-substituted lactams.
- Li, Hu,Wu, Hongguo,Zhang, Heng,Su, Yaqiong,Yang, Song,Hensen, Emiel J. M.
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p. 3778 - 3784
(2019/08/07)
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- Electroreductive coupling of aromatic ketones, aldehydes, and aldimines with α,β-unsaturated esters: Synthesis of 5-aryl substituted γ-butyrolactones and lactams
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The electroreductive intermolecular coupling of aromatic ketones and aldehydes with α,β-unsaturated esters in the presence of TMSCl gave the adducts as γ-trimethylsiloxy esters. The detrimethylsilylation of the adducts with TBAF afforded 5-aryl substituted γ-butyrolactones. The electroreductive coupling of N-(4-methoxyphenyl)-1-arylmethaneimines with methyl acrylate in the presence of TMSCl gave the adducts as methyl 4-aryl-4-((4-methoxyphenyl)amino)butanoates. The adducts were transformed to 5-aryl-γ-butyrolactams by cyclization with NaH and subsequent oxidation with CAN. (±)-Norcotinine was prepared from nicotinaldehyde by this method. The electroreductive coupling of aromatic ketones and aldimines with acrylonitrile in the presence of TMSCl gave 4-aryl-4-(trimethylsiloxy)butanenitriles and 4-aryl-4-((4-methoxyphenyl)amino)butanenitriles, respectively.
- Kise, Naoki,Hamada, Yusuke,Sakurai, Toshihiko
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p. 1143 - 1156
(2017/02/18)
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- Fused triazole derivatives as gamma secretase modulators
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The present invention provides fused bicyclic triazole derivatives of Formula (I) useful as gamma secretase modulators (GSM), for the treatment of Alzheimer's disease and related diseases.
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- FUSED TRIAZOLE DERIVATIVES AS GAMMA SECRETASE MODULATORS
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The present invention provides fused bicyclic triazole derivatives of Formula (I) useful as gamma secretase modulators (GSM), for the treatment of Alzheimer's disease and related diseases.
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