835-18-7Relevant academic research and scientific papers
Chiral-Directing-Group-Assisted Rhodium(III)-Catalyzed Asymmetric Addition of Inert Arene C?H Bond to Aldimines with Subsequent Intramolecular Cyclization
Cai, Xuhong,Chen, Wenkun,Nie, Ruifang,Wang, Jun
, p. 16611 - 16615 (2021/10/19)
By using a chiral directing group, an asymmetric rhodium(III)-catalyzed C?H bond addition to aldimines followed by intramolecular cyclization to form chiral isoindolinones has been achieved (up to 68 % yield, up to 93 % ee). A three-component variant that resembles Mannich reaction was also realized (41 % yield, 83 % ee). Product elaborations and preliminary mechanistic studies were described.
Tropylium-promoted Ritter reactions
Doan, Son H.,Hussein, Mohanad A.,Nguyen, Thanh Vinh
supporting information, p. 8901 - 8904 (2021/09/10)
The Ritter reaction used to be one of the most powerful synthetic tools to functionalize alcohols and nitriles, providing valuableN-alkyl amide products. However, this reaction has not been frequently used in modern organic synthesis due to its employment of strongly acidic and harsh reaction conditions, which often lead to complicated side reactions. Herein, we report the development of a new method using salts of the tropylium ion to promote the Ritter reaction. This method works well on a range of alcohol and nitrile substrates, giving the corresponding products in good to excellent yields. This reaction protocol is amenable to microwave and continuous flow reactors, offering an attractive opportunity for further applications in organic synthesis.
Palladium-catalyzed dehydrogenative C-H cyclization for isoindolinone synthesis
Abe, Masahiro,Inamoto, Kiyofumi,Kimachi, Tetsutaro,Tanaka, Saki,Ueta, Kaho
, p. 26988 - 26991 (2021/08/17)
In this paper Pd-catalyzed intramolecular dehydrogenative C(sp3)-H amidation for the synthesis of isoindolinones is described. This method features the use of a Pd/C catalyst and the addition of a stoichiometric amount of oxidant is not necessary. A mechanistic study suggested the possible formation of H2gas during the reaction.
Highly Robust Iron Catalyst System for Intramolecular C(sp3)?H Amidation Leading to γ-Lactams
Kweon, Jeonguk,Chang, Sukbok
supporting information, p. 2909 - 2914 (2020/12/11)
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.
COMPOUND HAVING BET INHIBITORY ACTIVITY AND PREPARATION METHOD AND USE THEREFOR
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Paragraph 0200-0201, (2020/12/22)
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.
Tuning Triplet Energy Transfer of Hydroxamates as the Nitrene Precursor for Intramolecular C(sp3)-H Amidation
Chang, Sukbok,Jung, Hoimin,Keum, Hyeyun,Kweon, Jeonguk
supporting information, p. 5811 - 5818 (2020/04/10)
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.
Synthesis of Lactams via Ir-Catalyzed C-H Amidation Involving Ir-Nitrene Intermediates
Li, Xiaoxun,Liu, Jitian,Tang, Weiping,Wang, Shuojin,Ye, Wenjing,Zheng, Junrong
, (2020/03/19)
x-membered lactams were synthesized via either an amidation of sp3 C-H bonds or an electrophilic substitution of arenes via Ir-nitrene intermediates. With the employment of a readily available iridium catalyst in dichloromethane or hexafluoro-2-propanol, a wide range of lactams were synthesized in good to excellent yields with high selectivity.
Strategic Approach to the Metamorphosis of γ-Lactones to NH γ-Lactams via Reductive Cleavage and C-H Amidation
Jung, Hoi-Yun,Chang, Sukbok,Hong, Sungwoo
, p. 7099 - 7103 (2019/09/07)
A new approach has elaborated on the conversion of γ-lactones to the corresponding NH γ-lactams that can serve as γ-lactone bioisosteres. This approach consists of reductive C-O cleavage and an Ir-catalyzed C-H amidation, offering a powerful synthetic tool for accessing a wide range of valuable NH γ-lactam building blocks starting from γ-lactones. The synthetic utility was further demonstrated by the late-stage transformation of complex bioactive molecules and the asymmetric transformation.
Harnessing Secondary Coordination Sphere Interactions That Enable the Selective Amidation of Benzylic C-H Bonds
Jung, Hoimin,Schrader, Malte,Kim, Dongwook,Baik, Mu-Hyun,Park, Yoonsu,Chang, Sukbok
supporting information, p. 15356 - 15366 (2019/10/22)
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.
Palladium-Catalyzed Direct C-H Carbonylation of Free Primary Benzylamines: A Synthesis of Benzolactams
Zhang, Chunhui,Ding, Yongzheng,Gao, Yuzhen,Li, Shangda,Li, Gang
supporting information, p. 2595 - 2598 (2018/05/22)
A protocol for palladium-catalyzed C-H carbonylation of readily available free primary benzylamines using NH2 as the chelating group under an atmospheric pressure of CO has been achieved, providing a general, atom- and step-economic approach to
