20614-54-4Relevant academic research and scientific papers
Antioxidant activity of chalcones: The chemiluminescence determination of the reactivity and the quantum chemical calculation of the energies and structures of reagents and intermediates
Vasil'ev,Kancheva,Fedorova,Batovska,Trofimov
, p. 507 - 515 (2010)
Six antioxidants from the class of chalcones (ArOH), compounds from which flavonoids are obtained in nature, were studied. The antiradical activity of chalcones and a number of related compounds was determined by a chemiluminescence method using the scavenging of peroxide radicals ROO ? + ArOH → ROOH + OAr? (with the rate constant k 7) in a model reaction of diphenylmethane (RH) oxidation. The structures and energies of the reagents and intermediates were determined by semiempirical quantum chemical (PM3, PM6) calculations. 3,4-Dihydroxychalcone and caffeic acid, which have a catechol structure, that is, two neighboring OH groups in phenyl ring B, exhibited high antioxidant activity (k 7 ≈ 107 l mol-1 s-1); this is consistent with the lowest bond strengths D(ArO-H) of 79.2 and 76.6 kcal/mol, respectively. The abstraction of a hydrogen atom by the ROO? radical is the main reaction path of these compounds; however, the low stoichiometric coefficients of inhibition (f = 0.3-0.7) suggest a contribution of secondary and/or side reactions of ArOH and OAr?. In the other chalcones, the ArO-H bond is stronger (D(ArO-H) = 83-88 kcal/mol) and the antioxidant activity is lower (k7 = 104-105 l mol-1 s -1).
Benzylic Hydroperoxidation via Visible-Light-Induced Csp3-H Activation
Inoa, Joan,Patel, Mansi,Dominici, Grecia,Eldabagh, Reem,Patel, Anjali,Lee, John,Xing, Yalan
, p. 6181 - 6187 (2020/05/22)
A highly efficient benzylic hydroperoxidation has been realized through a visible-light-induced Csp3-H activation. We believe that this reaction undergoes a direct HAT mechanism catalyzed by eosin Y. This approach features the use of a metal-free catalyst (eosin Y), an energy-economical light source (blue LED), and a sustainable oxidant (molecular oxygen). Primary, secondary, and tertiary hydroperoxides as well as silyl, benzyl, and acyl peroxides were successfully prepared with good yields and excellent functional group compatibility.
Indium-Mediated Synthesis of Benzylic Hydroperoxides
Hou, Yuxuan,Hu, Jinjin,Xu, Ruigang,Pan, Shulei,Zeng, Xiaofei,Zhong, Guofu
supporting information, p. 4428 - 4432 (2019/06/17)
An indium(0)-metal-mediated efficient synthesis of benzylic hydroperoxides is described. The reaction proceeds efficiently with a broad range of benzyl bromides under aerobic conditions at room temperature to afford benzyl hydroperoxides in good to excellent yields. In addition, the tandem hydroperoxidation-Michael addition of (E)-1-(bromomethyl)-2-(2-nitrovinyl)benzene was also demonstrated.
Fabrication of CuCr2O4 spinel nanoparticles: A potential catalyst for the selective oxidation of cycloalkanes via activation of Csp3-H bond
Acharyya, Shankha S.,Ghosh, Shilpi,Adak, Shubhadeep,Tripathi, Deependra,Bal, Rajaram
supporting information, p. 145 - 150 (2015/01/09)
We report here preparation of CuCr2O4 spinel nanoparticle catalyst, mediated by cationic surfactant CTAB in hydrothermal route. XRD revealed the formation of CuCr2O4 spinel phase and TEM showed the particle size of 30-60 nm. The catalyst was speculated to be highly active for selective oxidation of cyclohexane to cyclohexanone with H2O2. A cyclohexane conversion of 70% with 85% cyclohexanone selectivity was achieved over this catalyst at 50 °C temperature. Moreover, the catalyst did not show any significant activity loss even after 8 reuses and proved its efficacy in the oxidation of other cycloalkanes also.
Rate Constants for Reduction of substituted Methylperoxyl Radicals by Ascorbate Ions and N,N,N',N'-tetramethyl-p-phenylenediamine
Neta, P.,Huie, R. E.,Mosseri, S.,Shastri, L. V.,Mittal, J. P.,et al.
, p. 4099 - 4104 (2007/10/02)
Absolute rate constants (k) for reduction of substituted methylperoxyl radicals by ascorbate ions and by TMPD (N,N,N',N'-tetramethyl-p-phenylenediamine) in aqueous solutions have been determined by pulse radiolysis.The rate constants vary from 1E6 to 1E9 M-1 s-1, increasing as the electron-withdraving capacity of the substituent on the peroxyl group increases.Linear correlations are observed between log k and the Taft substituents ?* for a wide variety of substituents, but not all substituents fit the same line.In the case of ascorbate as reductant, the points for peroxyl radicals that contain halogens on the α-carbon lie on a different line (ρ*=0.41) than that for the other substituents (ρ*=1.25).In the case of TMPD there are alsotwo families of peroxyl radicals: Those comprimising the electron-donating groups Me through t-Bu (ρ=5.6) and those containing electron-withdrawing substituents (ρ*=0.64).
