495-18-1Relevant academic research and scientific papers
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.
Hydroxamate represents a versatile zinc binding group for the development of new carbonic anhydrase inhibitors
Di Fiore, Anna,Maresca, Alfonso,Supuran, Claudiu T.,De Simone, Giuseppina
, p. 8838 - 8840 (2012)
Hydroxamates (R-CONHOH) have been scarcely investigated as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors (CAIs). An inhibition/structural study of PhCONHOH is reported against all human isoforms. Comparing aliphatic (R = Me and CF3) and aromatic (R = Ph) hydroxamates as CAIs, we prove that CONHOH is a versatile zinc binding group. Depending on the nature of the R moiety, it can adopt different coordination modes to the catalytic ion within the CA active site.
Large Stereoelectronic Effect in 1,3-Dehydrohalogenation to form a 1,3-Dipole
Hegarty, Anthony F.,Mullane, Maria
, p. 229 - 230 (1984)
The E-hydroximidoyl chloride (5), prepared on photoisomerisation of (1) to (2) and by subsequent hydrolysis, is shown to lose HCl to give benzonitrile oxide 6*107 fold slower than the Z-isomer (3).
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.
Suicide nucleophilic attack: Reactions of benzohydroxamate anion with bis(2,4-dinitrophenyl) phosphate
Orth, Elisa S.,Da Silva, Pedro L. F.,Mello, Renata S.,Bunton, Clifford A.,Milagre, Humberto M. S.,Eberlin, Marcos N.,Fiedler, Haidi D.,Nome, Faruk
, p. 5011 - 5016 (2009)
(Chemical Equation Presented) The reaction between the benzohydroxamate anion (BHO-) and bis(2,4-dinitrophenyl)phosphate (BDNPP) has been examined kinetically, and the products were characterized by mass and NMR spectroscopy. The nucleophilic attack of BHO- follows two reaction paths: (i) at phosphorus, giving an unstable intermediate that undergoes a Lossen rearrangement to phenyl isocyanate, aniline, diphenylurea, and O-phenylcarbamyl benzohydroxamate; and (ii) on the aromatic carbon, giving an intermediate that was detected but slowly decomposes to aniline and 2,4-dinitrophenol. Thus, the benzohydroxamate anion can be considered a self-destructive molecular scissor since it reacts and loses its nucleophilic ability.
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.
Photochemical Activation of Aromatic Aldehydes: Synthesis of Amides, Hydroxamic Acids and Esters
Nikitas, Nikolaos F.,Apostolopoulou, Mary K.,Skolia, Elpida,Tsoukaki, Anna,Kokotos, Christoforos G.
supporting information, p. 7915 - 7922 (2021/05/03)
A cheap, facile and metal-free photochemical protocol for the activation of aromatic aldehydes has been developed. Utilizing thioxanthen-9-one as the photocatalyst and cheap household lamps as the light source, a variety of aromatic aldehydes have been activated and subsequently converted in a one-pot reaction into amides, hydroxamic acids and esters in good to high yields. The applicability of this method was highlighted in the synthesis of Moclobemide, a drug against depression and social anxiety. Extended and detailed mechanistic studies have been conducted, in order to determine a plausible mechanism for the reaction.
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.
Alternating Current Electrolysis as Efficient Tool for the Direct Electrochemical Oxidation of Hydroxamic Acids for Acyl Nitroso Diels–Alder Reactions
F?hrmann, Jan,Hilt, Gerhard
supporting information, p. 20313 - 20317 (2021/08/12)
The acyl nitroso Diels–Alder reaction of 1,3-dienes with electrochemically oxidised hydroxamic acids is described. By using alternating current electrolysis, their typical electro-induced decomposition could be suppressed in favour of the 1,2-oxazine cycloaddition products. The reaction was optimised using Design of Experiments (DoE) and a sensitivity test was conducted. A mixture of triethylamine/hexafluoroisopropanol served as supporting electrolyte in dichloromethane, thus giving products of high purity after evaporation of the volatiles without further purification. The optimised reaction conditions were applied to various 1,3-dienes and hydroxamic acids, giving up to 96 % isolated yield.
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.
