495-18-1Relevant articles and documents
Boronic Acid-Catalyzed, Highly Enantioselective Aza-Michael Additions of Hydroxamic Acid to Quinone Imine Ketals
Hashimoto, Takuya,Gálvez, Alberto Osuna,Maruoka, Keiji
, p. 16016 - 16019 (2015)
Boronic acid is one of the most versatile organic molecules in chemistry. Its uses include organic reactions, molecular recognition, assembly, and even medicine. While boronic acid catalysis, which utilizes an inherent catalytic property, has become an important research objective, it still lags far behind other boronic acid chemistries. Here, we report our discovery of a new boronic acid catalysis that enables the aza-Michael addition of hydroxamic acid to quinone imine ketals. By using 3-borono-BINOL as a chiral boronic acid catalyst, this reaction could be implemented in a highly enantioselective manner, paving the way to densely functionalized cyclohexanes.
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Goldenberg,Spoerri
, p. 1327,1328 (1958)
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Synthesis, structure and magnetic properties of phenylhydroxamate-based coordination clusters
Tirfoin, Rmi,Chamoreau, Lise-Marie,Li, Yanling,Fleury, Benoit,Lisnard, Laurent,Journaux, Yves
, p. 16805 - 16817 (2014)
The strategic recombination of preformed coordination clusters in the presence of polymodal bridging ligands has successfully led to the characterisation of five new compounds of structural and magnetic interest. Indeed using the dinuclear complex [M2(H2O)(piv)4(Hpiv)4] (M = Co, Ni; Hpiv = pivalic acid) as starting material and reacting it with phenylhydroxamic acid (H2pha) has yielded the four tetrametallic coordination clusters [Co4(Hpha)2(piv)6(Hpiv)4] (1), [Ni4(Hpha)2(piv)6(Hpiv)2(DMF)2] (2), [Co4(Hpha)2(piv)6(EtOH)2(H2O)2] (3), [Ni4(Hpha)2(piv)6(EtOH)2(H2O)2] (4) and the hexanuclear complex [Co6(Hpha)4(piv)8(EtOH)2]·EtOH (5). All the compounds have been structurally characterised revealing a particular binding mode for the hydroxamate ligand. The study of their magnetic properties has been performed and the modelling of these properties has been done using the appropriate hamiltonians for each compound. The experimental data and their modelling show non-zero spin ground states for compounds 4 and 5.
Fast and Cysteine-Specific Modification of Peptides, Proteins and Bacteriophage Using Chlorooximes
Chen, Fa-Jie,Zheng, Mengmeng,Nobile, Vincent,Gao, Jianmin
, (2022/03/15)
This work reports a novel chlorooxime mediated modification of native peptides and proteins under physiologic conditions. This method features fast reaction kinetics (apparent k2=306±4 M?1s?1 for GSH) and exquisite selectivity for cysteine residues. This cysteine conjugation reaction can be carried out with just single-digit micromolar concentrations of the labeling reagent. The conjugates show high stability towards acid, base, and external thiol nucleophiles. A nitrile oxide species generated in situ is likely involved as the key intermediate. Furthermore, a bis-chlorooxime reagent is synthesized to enable facile Cys-Cys stapling in native peptides and proteins. This highly efficient cysteine conjugation and stapling was further implemented on bacteriophage to construct chemically modified phage libraries.
P(III)-Assisted Electrochemical Access to Ureas via in situ Generation of Isocyanates from Hydroxamic Acids
Meng, Haiwen,Sun, Kunhui,Xu, Zhimin,Tian, Lifang,Wang, Yahui
supporting information, p. 1768 - 1772 (2021/03/26)
An external oxidant-free protocol for the generation of isocyanates from hydroxamic acids assisted by trivalent phosphine under mild electrochemical conditions was reported. The process started with the anodic oxidation of hydroxamic acids, followed by reacting with phosphine to form corresponding alkoxyphosphoniums and subsequent rearrangement with the release of tri-substituted phosphine oxide as the driving force to give isocyanates, which were trapped by N-based nucleophiles to produce various ureas. This method provides a broadly applicable procedure to access isocyanate intermediates under mild electrochemical conditions.
Direct synthesis of benzoxazinones via Cp*Co(III)-catalyzed C–H activation and annulation of sulfoxonium ylides with dioxazolones
Yu, Yongqi,Xia, Zhen,Wu, Qianlong,Liu, Da,Yu, Lin,Xiao, Yuanjiu,Tan, Ze,Deng, Wei,Zhu, Gangguo
supporting information, p. 1263 - 1266 (2020/10/08)
A highly novel and direct synthesis of benzoxazinones was developed via Cp*Co(III)-catalyzed C–H activation and [3 + 3] annulation between sulfoxonium ylides and dioxazolones. The reaction is conducted under base-free conditions and tolerates various functional groups. Starting from diverse readily available sulfoxonium ylides and dioxazolones, a variety of benzoxazinones could be synthesized in one step in 32%-75% yields.