29903-62-6Relevant academic research and scientific papers
What are the differences between ascorbic acid and NADH as hydride and electron sources in vivo on thermodynamics, kinetics, and mechanism?
Zhu, Xiao-Qing,Mu, Yuan-Yuan,Li, Xiu-Tao
, p. 14794 - 14811 (2011)
Ascorbic acid (AscH2) and dihydronicotinamide adenine dinucleotide (NADH) are two very important natural redox cofactors, which can be used as hydride, electron, and hydrogen atom sources to take part in many important bioreduction processes in vivo. The differences of the two natural reducing agents as hydride, hydrogen atom, and electron donors in thermodynamics, kinetics, and mechanisms were examined by using 5,6-isopropylidene ascorbate (iAscH-) and β-d-glucopyranosyl-1, 4-dihydronicotinamide acetate (GluNAH) as their models, respectively. The results show that the hydride-donating ability of iAscH- is smaller than that of GluNAH by 6.0 kcal/mol, but the electron-donating ability and hydrogen-donating ability of iAscH- are larger than those of GluNAH by 20.8 and 8.4 kcal/mol, respectively, which indicates that iAscH- is a good electron donor and a good hydrogen atom donor, but GluNAH is a good hydride donor. The kinetic intrinsic barrier energy of iAscH- to release hydride anion in acetonitrile is larger than that of GluNAH to release hydride anion in acetonitrile by 6.9 kcal/mol. The mechanisms of hydride transfer from iAscH- and GluNAH to phenylxanthium perchlorate (PhXn+), a well-known hydride acceptor, were examined, and the results show that hydride transfer from GluNAH adopted a one-step mechanism, but the hydride transfer from iAscH- adopted a two-step mechanism (e-H?). The thermodynamic relation charts (TRC) of the iAscH- family (including iAscH-, iAscH?, iAsc?-, and iAsc) and of the GluNAH family (including GluNAH, GluNAH?+, GluNA?, and GluNA+) in acetonitrile were constructed as Molecule ID Cards of iAscH- and of GluNAH in acetonitrile. By using the Molecule ID Cards of iAscH- and GluNAH, the character chemical properties not only of iAscH- and GluNAH but also of the various reaction intermediates of iAscH- and GluNAH all have been quantitatively diagnosed and compared. It is clear that these comparisons of the thermodynamics, kinetics, and mechanisms between iAscH- and GluNAH as hydride and electron donors in acetonitrile should be quite important and valuable to diagnose and understand the different roles and functions of ascorbic acid and NADH as hydride, hydrogen atom, and electron sources in vivo.
LDA-Mediated Synthesis of Triarylmethanes by Arylation of Diarylmethanes with Fluoroarenes at Room Temperature
Ji, Xinfei,Huang, Tao,Wu, Wei,Liang, Fang,Cao, Song
supporting information, p. 5096 - 5099 (2015/11/03)
A practical and convenient approach for the secondary C(sp3)-H arylation of diarylmethanes with various fluoroarenes is described. The reaction proceeds smoothly in the presence of LDA (lithium diisopropylamide) at room temperature and affords triarylmethanes in moderate to high yields.
A classical but new kinetic equation for hydride transfer reactions
Zhu, Xiao-Qing,Deng, Fei-Huang,Yang, Jin-Dong,Li, Xiu-Tao,Chen, Qiang,Lei, Nan-Ping,Meng, Fan-Kun,Zhao, Xiao-Peng,Han, Su-Hui,Hao, Er-Jun,Mu, Yuan-Yuan
, p. 6071 - 6089 (2013/09/12)
A classical but new kinetic equation to estimate activation energies of various hydride transfer reactions was developed according to transition state theory using the Morse-type free energy curves of hydride donors to release a hydride anion and hydride acceptors to capture a hydride anion and by which the activation energies of 187 typical hydride self-exchange reactions and more than thirty thousand hydride cross transfer reactions in acetonitrile were safely estimated in this work. Since the development of the kinetic equation is only on the basis of the related chemical bond changes of the hydride transfer reactants, the kinetic equation should be also suitable for proton transfer reactions, hydrogen atom transfer reactions and all the other chemical reactions involved with breaking and formation of chemical bonds. One of the most important contributions of this work is to have achieved the perfect unity of the kinetic equation and thermodynamic equation for hydride transfer reactions. The Royal Society of Chemistry.
