88-14-2Relevant articles and documents
Kinetic and mechanistic analysis of oxidation of 2-furoic hydrazide by hexachloroirradate(IV) in a wide pH range
Yao, Haiping,Tian, Hongwu,Xu, Liyao,Xia, Yanqing,Zhou, Li,Liu, Chunli,Shi, Tiesheng
, p. 771 - 777 (2019)
Oxidation of 2-furoic hydrazide (FH) by hexachloroiridate(IV) ([IrCl6]2?) was studied kinetically in a wide pH range in aqueous solution of 1.0?M ionic strength. The oxidation reaction followed well-defined second-order kinetics: ? d[IrCl6 2?]/dt = k′[FH]tot[IrCl6 2?], where [FH]tot denotes the total concentration of FH and k′ stands for the observed second-order rate constants. The established k′–pH profile displays that k′ increases drastically with pH and a plateau region exists between pH 4 and 6. A stoichiometric ratio of Δ[FH]tot/Δ[IrCl6 2?] = 1/4?was revealed by spectrophotometric titrations. 1H NMR spectroscopic studies indicated that FH was cleanly oxidized to 2-furoic acid. The kinetic data suggest a reaction mechanism in which all the three protolysis species of FH react with [IrCl6]2? in parallel, forming the rate-determining steps. Two stabilized hydrazyl radicals are generated in the rate-determining steps, in which a single electron is transferred to [IrCl6]2?. The two hydrazyl radicals react rapidly in consecutive steps requiring 3?mol of Ir(IV) to form 2-furoic acid as the final product. Rate constants of the rate-determining steps were deduced through a simulation of the rate expression to the k′–pH dependency data. Values of these rate constants demonstrate that the three protolysis species of FH have a huge reactivity span, changing by about 109 times toward reduction in [IrCl6]2? and that FH can be readily oxidized in neutral and basic media. Rapid scan spectra and the measured activation parameters suggest that an outer-sphere electron transfer is probably taking place in each of the rate-determining steps. This is the first kinetic study on the oxidation reactions of FH and provides concurrently the protolysis constants of FH (pKa1 = 3.04 ± 0.08 and pKa2 = 11.6 ± 0.1) at 25.0?°C and 1.0?M ionic strength.
Transformation of Thioacids into Carboxylic Acids via a Visible-Light-Promoted Atomic Substitution Process
Fu, Qiang,Liang, Fu-Shun,Lou, Da-Wei,Pan, Gao-Feng,Wang, Rui,Wu, Min,Xie, Kai-Jun
, p. 2020 - 2024 (2022/03/31)
A visible-light-promoted atomic substitution reaction for transforming thiocacids into carboxylic acids with dimethyl sulfoxide (DMSO) as the oxygen source has been developed, affording various alkyl and aryl carboxylic acids in over 90% yields. The atomic substitution process proceeds smoothly through the photochemical reactivity of the formed hydrogen-bonding adduct between thioacids and DMSO. A DMSO-involved proton-coupled electron transfer (PCET) and the simultaneous generation of thiyl and hydroxyl radicals are proposed to be key steps for realizing the transformation.
Synthesis, biological evaluation and molecular docking studies of indeno [1, 2-c] pyrazol derivatives as inhibitors of mitochondrial malate dehydrogenase 2 (MDH2)
Ahmadi, Farzaneh,Engel, Matthias,Baradarani, Mehdi M.
, (2021/03/15)
Hypoxia inducible factor-1 (HIF-1) is a pivotal transcription factor, which is strongly correlated with the induction of angiogenesis, tumor survival, metastasis, and cell proliferation, making it a pivotal therapeutic target for solid tumor therapeutic agents. Herein, a new series of multi-functional chemical probes were designed including principal groups, viz. adamantyl and indene, at various locations of the parent compound LW6. Molecular docking studies were performed on the designed compounds and their relationship with HIF-1α and malate dehydrogenase 2 (MDH2). Inhibition of MDH2 by our compounds was expected to decrease the NADH level. Indeed, treatment of the breast cancer cell line 4T1 led to a strong reduction of the NADH concentration. The greatest reduction in NADH production in mitochondria was observed with (E)-3-(4-((3r, 5r, 7r)-adamantan-1-yl) phenoxy)-N-(5-(piperidine-1-carbonyl)-1, 4-dihydroindeno [1, 2-c] pyrazol-3-yl) acrylamide (18: IC50 = 59 nM), and has the best inhibitory potential under hypoxic conditions (MCF-7: IC50 = 57 nM). This compound also gave one of the highest docking “higher than the score obtained with LW6 in parallel (?31.63 kcal/mol) in the initial docking runs (PDB Code: 4WLO). Other related compounds with good yields were also synthesized from docking results, and all the synthesized compounds (14, 18, 22, 26, 29, 30) were evaluated in vitro on human adenocarcinoma cell lines.
Hydrogen-Binding-Initiated Activation of O?H Bonds on a Nitrogen-Doped Surface for the Catalytic Oxidation of Biomass Hydroxyl Compounds
Liu, Xin,Luo, Yang,Ma, Hong,Zhang, Shujing,Che, Penghua,Zhang, Meiyun,Gao, Jin,Xu, Jie
, p. 18103 - 18110 (2021/07/14)
Hydrogen binding of molecules on solid surfaces is an attractive interaction that can be used as the driving force for bond activation, material-directed assembly, protein protection, etc. However, the lack of a quantitative characterization method for hydrogen bonds (HBs) on surfaces seriously limits its application. We measured the standard Gibbs free energy change (ΔG0) of on-surface HBs using NMR. The HB-accepting ability of the surface was investigated by comparing ΔG0 values employing the model biomass platform 5-hydroxymethylfurfural on a series of Co-N-C-n catalysts with adjustable electron-rich nitrogen-doped contents. Decreasing ΔG0 improves the HB-accepting ability of the nitrogen-doped surface and promotes the selectively initiated activation of O?H bonds in the oxidation of 5-hydroxymethylfurfural. As a result, the reaction kinetics is accelerated. In addition to the excellent catalytic performance, the turnover frequency (TOF) for this oxidation is much higher than for reported non-noble-metal catalysts.