2055-40-5Relevant academic research and scientific papers
In-situ facile synthesis novel N-doped thin graphene layer encapsulated Pd@N/C catalyst for semi-hydrogenation of alkynes
Lin, Shanshan,Liu, Jianguo,Ma, Longlong,Sun, Jiangming
, (2021/12/03)
Transition metal-catalyzed semi-hydrogenation of alkynes has become one of the most popular methods for alkene synthesis. Specifically, the noble metal Pd, Rh, and Ru-based heterogeneous catalysts have been widely studied and utilized in both academia and industry. But the supported noble metal catalysts are generally suffering from leaching or aggregation during harsh reaction conditions, which resulting low catalytic reactivity and stability. Herein, we reported the facile synthesis of nitrogen doped graphene encapsulated Pd catalyst and its application in the chemo-selective semi-hydrogenation of alkynes. The graphene layer served as “bulletproof” over the active Pd Nano metal species, which was confirmed by X-ray and TEM analysis, enhanced the catalytic stability during the reaction conditions. The optimized prepared Pd@N/C catalyst showed excellent efficiency in semi-hydrogenation of phenylacetylene and other types of alkynes with un-functionalized or functionalized substituents, including the hydrogenation sensitive functional groups (NO2, ester, and halogen).
Indene formation upon borane-induced cyclization of arylallenes, 1,1-carboboration, and retro-hydroboration
Hasenbeck, Max,Wech, Felix,Averdunk, Arthur,Becker, Jonathan,Gellrich, Urs
supporting information, p. 5518 - 5521 (2021/06/12)
We herein report the reaction of arylallenes with tris(pentafluorophenyl)borane that yields pentafluorophenyl substituted indenes. The tris(pentafluorophenyl)borane induces the cyclization of the allene and transfers a pentafluorophenyl ring in the course of this reaction. A Hammett plot analysis and DFT computations indicate a 1,1-carboboration to be the C-C bond-forming step.
Overcoming Selectivity Issues in Reversible Catalysis: A Transfer Hydrocyanation Exhibiting High Kinetic Control
Bhawal, Benjamin N.,Ehinger, Christian,Morandi, Bill,Reisenbauer, Julia C.
supporting information, p. 10914 - 10920 (2020/07/13)
Reversible catalytic reactions operate under thermodynamic control, and thus, establishing a selective catalytic system poses a considerable challenge. Herein, we report a reversible transfer hydrocyanation protocol that exhibits high selectivity for the thermodynamically less favorable branched isomer. Selectivity is achieved by exploiting the lower barrier for C-CN oxidative addition and reductive elimination at benzylic positions in the absence of a cocatalytic Lewis acid. Through the design of a novel type of HCN donor, a practical, branched-selective, HCN-free transfer hydrocyanation was realized. The synthetically useful resolution of a mixture of branched and linear nitrile isomers was also demonstrated to underline the value of reversible and selective transfer reactions. In a broader context, this work demonstrates that high kinetic selectivity can be achieved in reversible transfer reactions, thus opening new horizons for their synthetic applications.
Design, synthesis of novel 4,5-dihydroisoxazole-containing benzamide derivatives as highly potent FtsZ inhibitors capable of killing a variety of MDR Staphylococcus aureus
Song, Di,Bi, Fangchao,Zhang, Nan,Qin, Yinhui,Liu, Xingbang,Teng, Yuetai,Ma, Shutao
supporting information, (2020/09/11)
Antibiotic resistance among clinically significant bacterial pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) is becoming a prevalent threat to public health, and new antibacterial agents with novel mechanisms of action hence are in an urgent need. As a part of continuing effort to develop antibacterial agents, we rationally designed and synthesized two series of 4,5-dihydroisoxazol-5-yl and 4,5-dihydroisoxazol-3-yl-containing benzamide derivatives that targeted the bacterial cell division protein FtsZ. Evaluation of their activity against a panel of Gram-positive and -negative pathogens revealed that compound A16 possessing the 4,5-dihydroisoxazol-5-yl group showed outstanding antibacterial activity (MIC, ≤0.125–0.5 μg/mL) against various testing strains, including methicillin-resistant, penicillin-resistant and clinical isolated S. aureus strains. Besides, further mouse infection model revealed that A16 could be effective in vivo and non-toxic to Hela cells. Finally, a detailed discussion of structure-activity relationships was conducted, referring to the docking results. It is worth noting that substituting a 4,5-dihydroisoxazole ring for the isoxazole ring not only broadened the antibacterial spectrum but also resulted in a significant increase in antibacterial activity against S. aureus strains. Taken together, these results suggest a promising chemotype for the development of new FtsZ-targeting bactericidal agents.
Intermolecular Radical C(sp3)?H Amination under Iodine Catalysis
Bosnidou, Alexandra E.,Mu?iz, Kilian
supporting information, p. 7485 - 7489 (2019/04/30)
The direct amination of aliphatic C?H bonds has remained one of the most tantalizing transformations in organic chemistry. Herein, we report on a unique catalyst system, which enables the elusive intermolecular C(sp3)?H amination. This practical synthetic strategy provides access to aminated building blocks and fosters innovative multiple C?H amination within a new approach to aminated heterocycles. The synthetic utility is demonstrated by the synthesis of four relevant pharmaceuticals.
Electrosynthesis of vinyl sulfones from alkenes and sulfonyl hydrazides mediated by KI: Аn electrochemical mechanistic study
Terent'ev, Alexander O.,Mulina, Olga M.,Pirgach, Dmitry A.,Ilovaisky, Alexey I.,Syroeshkin, Mikhail A.,Kapustina, Nadezhda I.,Nikishin, Gennady I.
supporting information, p. 6871 - 6879 (2017/11/06)
A variety of vinyl sulfones were prepared from alkenes and sulfonyl hydrazides via electrochemical oxidative sulfonylation. The reaction proceeds in an experimentally convenient undivided electrochemical cell equipped with graphite and iron electrodes employing KI as a redox catalyst and a supporting electrolyte. Applying extremely high current density up to 270 mA/cm2 permits rapid synthesis in a compact reactor and with small surface area electrodes. A possible reaction mechanism was proposed with the use of cyclic voltammetry. It is the combination of anodic and cathodic processes in this reaction that makes it possible to obtain products under mild conditions with yields from moderate to high.
Copper(i)-mediated synthesis of β-hydroxysulfones from styrenes and sulfonylhydrazides: An electrochemical mechanistic study
Terent'Ev, Alexander O.,Mulina, Olga M.,Pirgach, Dmitry A.,Demchuk, Dmitry V.,Syroeshkin, Mikhail A.,Nikishin, Gennady I.
, p. 93476 - 93485 (2016/10/17)
Copper(i) halides were used as mediators in the synthesis of β-hydroxysulfones via the oxysulfonylation of styrenes using sulfonylhydrazides. The feature of the developed process lies in the combination of a copper(i) salt with oxygen - the stoichiometric oxidant. Copper(ii) species are responsible for the oxidation of sulfonylhydrazides, they are generated in small amounts in the O2/Cu(i)/Cu(ii) redox system, which is formed during the reaction. The combination of these three components enables one to obtain in the case of α-methylstyrenes only β-hydroxysulfones and in the case of α-unsubstituted styrenes, β-hydroxysulfones as the main products and β-ketosulfones as the by-products. With good yields β-hydroxysulfones were prepared by reduction of the reaction mixture containing both products β-hydroxysulfones and β-ketosulfones with NaBH4. An electrochemical study revealed that the Cu(i)/Cu(II) pair can serve as an effective mediator of β-hydroxysulfones formation via redox processes.
Bis(1-cyanovinyl acetate) Is a Linear Precursor to 3-Oxidopyrylium Ions
Wilkerson-Hill, Sidney Malik,Sawano, Shota,Sarpong, Richmond
, p. 11132 - 11144 (2016/11/28)
Herein we describe the first approach to 3-oxidopyrylium ions from a linear precursor. Heating bis(1-cyanovinyl acetate) in the presence of a trace amount of pyridinium p-toluenesulfonate results in a series of acyl group transfers and an intramolecular cyclization event to form a 3-oxidopyrylium ion that can be trapped by reaction with several dipolarophiles. When treated with dienes, the result is a sequential [5 + 2]/[4 + 2] cycloaddition reaction that provides sp3-rich products of high molecular complexity.
Highly selective Wacker reaction of styrene derivatives: A green and efficient aerobic oxidative process promoted by benzoquinone/NaNO 2/HClO4 under mild conditions
Zhang, Guofu,Xie, Xiaoqiang,Wang, Yong,Wen, Xin,Zhao, Yun,Ding, Chengrong
supporting information, p. 2947 - 2950 (2013/07/25)
A green and efficient catalytic redox system for the aerobic oxidative Wacker oxidation of styrene derivatives at room temperature using molecular oxygen as the terminal oxidant without copper chloride has been developed. The newly developed system exhibited excellent catalytic activity for the smooth transformation of terminal styrene derivatives to the desired methyl ketones with up to 96% yield and >99% selectivity. The Royal Society of Chemistry 2013.
A new and facile method for stereoselective synthesis of (E)-styryl bromides by the reduction of 1,1-dibromoalkenes using LiAlH4-EtOAc (1:1)
Horibe, Hideo,Kondo, Kazuhiro,Okuno, Hiroaki,Aoyama, Toyohiko
, p. 986 - 988 (2007/10/03)
A facile method for stereoselective synthesis of (E)-styryl bromides by the reduction of 1,1-dibromoalkenes using LiAlH4-EtOAc (1:1) is described. We believe that the present procedure is a good alternative to the Tokuda's microwave method with good stereoselectivity.
