- O -Phenylenediamine: A privileged pharmacophore of ferrostatins for radical-trapping reactivity in blocking ferroptosis
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Ferroptosis is a non-apoptotic, iron dependent form of regulated cell death that is characterized by the accumulation of lipid hydroperoxides. It has drawn considerable attention owing to its putative involvement in diverse neurodegenerative diseases. Ferrostatins are the first identified inhibitors of ferroptosis and they inhibit ferroptosis by efficiently scavenging free radicals in lipid bilayers. However, their further medicinal application has been limited due to the deficient knowledge of the lipid peroxyl radical-trapping mechanism. In this study, experimental and theoretical methods were performed to illustrate the possible lipid hydroperoxide inhibition mechanism of ferrostatins. The results show that an ortho-amine (-NH) moiety from ferrostatins can simultaneously interact with lipid radicals, and then form a planar seven-membered ring in the transition state, and finally present greater reactivity. NBO analysis shows that the formed planar seven-membered ring forces ortho-amines into better alignment with the aromatic π-system. It significantly increases the magnitudes of amine conjugation and improves spin delocalization in the transition state. Additionally, a classical H-bond type interaction was discovered between a radical and an o-NH group as another transition state stabilizing effect. This type of radical-trapping mechanism is novel and has not been found in diphenylamine or traditional polyphenol antioxidants. It can be said that o-phenylenediamine is a privileged pharmacophore for the design and development of ferroptosis inhibitors.
- Sheng, Xie-Huang,Cui, Cheng-Cheng,Shan, Chao,Li, Yu-Zhen,Sheng, Duo-Hong,Sun, Bin,Chen, De-Zhan
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p. 3952 - 3960
(2018/06/11)
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- Palladium-Catalyzed Synthesis of N-Cyclohexyl Anilines from Phenols with Hydrazine or Hydroxylamine via N-N/O Cleavage
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Direct access to amines from biomass-based phenols via deoxygenative transformation remains greatly challenging in organic synthesis. Herein, we present a palladium-catalyzed deoxygenative amination of phenols (and their benzyl ether) with hydrazine as nitrogen source. The hydroxylamine/formic acid can be substituted for hydrazine in some cases. This deoxyamination features the involvement of a complex C?O bond and N?N/O bond-cleavage process and allows for the construction of N-substituted cyclohexyl anilines from an array of phenols by finely controlling the reaction conditions in moderate to good yields. (Figure presented.).
- Li, Jiang-Sheng,Qiu, Zihang,Li, Chao-Jun
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p. 3648 - 3653
(2017/09/13)
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- N-Alkylation of amines with phenols over highly active heterogeneous palladium hydride catalysts
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Phenols are directly converted to secondary amines in considerable yield via hydrogenation and amination tandem reaction over Al2O3 supported palladium hydride (PdHx) bi-functional catalyst. Note that this system proceeds efficiently with mild conditions under H2 atmosphere, which was difficult to achieve in previous reports. The catalyst and the mechanism of reaction are both studied. Furthermore, various secondary amines can be formed in good yields under this conversion system.
- Yan, Long,Liu, Xin-Xin,Fu, Yao
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p. 109702 - 109705
(2016/11/30)
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- Preparation of aryl-alkylamines via electrophilic amination of functionalized arylazo tosylates with alkylzinc reagents
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A new electrophilic amination reaction of functionalized arylazo tosylates with alkylzinc halides or dialkylzinc reagents in THF leads to the corresponding hydrazines. A facile cleavage of the N-N bond is achieved using Raney nickel in refluxing ethanol, leading to substituted secondary aryl-alkylamines in 45-79% yield.
- Sinha, Pradipta,Kofink, Christiane C.,Knochel, Paul
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p. 3741 - 3744
(2007/10/03)
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