抗坏血酸自由基 | 213530-28-0

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 二氢呋喃
• 中文名称: 抗坏血酸自由基
• 英文名称: ascorbic acid radical
• 英文别名: Semidehydroascorbic acid
• CAS: 213530-28-0；1141863-90-2；1141863-91-3
• 化学式: C₆H₇O₆
• 分子量: 175.118
• InChiKey: LHFJOBMTAJJOTB-JLAZNSOCSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  -1.8
• 重原子数：
  12
• 可旋转键数：
  2
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.5
• 拓扑面积：
  88
• 氢给体数：
  3
• 氢受体数：
  5

反应信息

• 作为产物：
  描述：

  sodium ascorbate 在 乙二胺四乙酸 、 manganese(III)(5,10,15,20-tetrakis(N-ethylpyridinium-2-yl)porphyrinate) chloride 作用下， 以 aq. buffer 为溶剂， 生成 抗坏血酸自由基
  参考文献：
  名称：

  Rational Design of Superoxide Dismutase (SOD) Mimics: The Evaluation of the Therapeutic Potential of New Cationic Mn Porphyrins with Linear and Cyclic Substituents

  摘要：

  Our goal herein has been to gain further insight into the parameters which control porphyrin therapeutic potential. Mn porphyrins (MnTnOct-2-PyP5+, MnTnHexOE-2-PyP5+, MnTE-2-PyPhP5+, and MnTPhE-2-PyP5+ that bear the same positive charge and same number of carbon atoms at meso positions of porphyrin core were explored. The carbon atoms of their meso substituents are organized to form either linear or cyclic structures of vastly different redox properties, bulkiness, and lipophilicities. These Mn porphyrins were compared to frequently studied compounds, MnTE-2-PyP5+, MnTE-3-PyP5+, and MnTBAP(3-). All Mn(III) porphyrins (MnPs) have metal-centered reduction potential, E-1/2 for (MnP)-P-III/(MnP)-P-II redox couple, ranging from -194 to +340 mV versus NHE, log k(cat)(O-2(center dot-)) from 3.16 to 7.92, and log k(red)(ONOO-) from 5.02 to 7.53. The lipophilicity, expressed as partition between n-octanol and water, log POW, was in the range -1.67 to -7.67. The therapeutic potential of MnPs was assessed via: (i) in vitro ability to prevent spontaneous lipid peroxidation in rat brain homogenate as assessed by malondialdehyde levels; (ii) in vivo O-2(center dot-) specific assay to measure the efficacy in protecting the aerobic growth of SOD-deficient Saccharomyces cerevisiae; and (iii) aqueous solution chemistry to measure the reactivity toward major in vivo endogenous antioxidant, ascorbate. Under the conditions of lipid peroxidation assay, the transport across the cellular membranes, and in turn shape and size of molecule, played no significant role. Those MnPs of E-1/2 similar to +300 mV were the most efficacious, significantly inhibiting lipid peroxidation in 0.5-10 mu M range. At up to 200 mu M, MnTBAP(3-) (E-1/2 = -194 mV vs NHE) failed to inhibit lipid peroxidation, while MnTE-2-PyPhP(5+) with 129 mV more positive E-1/2 (-65 mV vs NHE) was fully efficacious at 50 mu M. The E-1/2 of (MnP)-P-III/(MnP)-P-II redox couple is proportional to the log k(cat)(O-2(center dot-)), i.e., the SOD-like activity of MnPs. It is further proportional to k(red)(ONOO-) and the ability of MnPs to prevent lipid peroxidation. In turn, the inhibition of lipid peroxidation by MnPs is also proportional to their SOD-like activity. In an in vivo S. cerevisiae assay, however, while E-1/2 predominates, lipophilicity significantly affects the efficacy of MnPs. MnPs of similar log P-OW and E-1/2, that have linear alkyl or alkoxyalkyl pyridyl substituents, distribute more easily within a cell and in turn provide higher protection to S. cerevisiae in comparison to MnP with bulky cyclic substituents. The bell-shape curve, with MnTE-2-PyP5+ exhibiting the highest ability to catalyze ascorbate oxidation, has been established and discussed. Our data support the notion that the SOD-like activity of MnPs parallels their therapeutic potential, though species other than O-2(center dot-), such as peroxynitrite, H2O2, lipid reactive species, and cellular reductants, may be involved in their mode(s) of action(s).

  DOI：

  10.1021/ic501329p

文献信息

• The thermal charge-transfer reduction of uranyl UO22+(VI) to UO2+(V) by various functionalized organic compounds, and evidence for possible spin-spin interactions between UO2+(V) and hydroxymethyl ( CH2OH) radical and between UO2+(V) and diphenyl sulfide radical cation (Ph2S+)
  作者：Xiaoping Sun、Derrick R.J. Kolling、Seth Deskins、Ethan Adkins

  DOI：10.1016/j.ica.2018.07.049

  日期：2018.11

  ArO radical (singlet, g = 1.98), respectively. Both EPR and UV-Vis studies indicate that the reactions followed the ground-state charge-transfer mechanisms similar to that of the UO22+/methanol reaction. EPR evidence supported formation of the [UO2+, Ph2S+ ] ion-radical pair in the charge-transfer reaction of UO22+ and Ph2S and spin-spin interactions within the ion-radical pair. The sulfuric-acid-catalyzed

  摘要线性铀酰UO22 +（VI）阳离子（D∞h对称）在无水甲醇和甲醇-水混合物中的UV-Vis光谱中于350–400 nm处显示强而宽的吸收。吸收强度（由375 nm处的吸光度表示）分别直接与甲醇和UO22 +（VI）的摩尔浓度成正比。线性关系表明形成了电子给体-受体（EDA）络合物[UO22 +，CH3OH]。在350–400 nm处的吸收来自[UO22 +，CH3OH]络合物中从CH3OH（电子供体）到UO22 +（电子受体）的电荷转移（单电子转移）。对UO22 + -CH3OH和UO22 + -CH3OH-H2O各种混合物的电子顺磁共振（EPR）研究表明，电荷转移在黑暗中也很缓慢，导致CH3OH将UO22 +（VI）热还原为UO2 +（V）（单峰，g = 2.08），并且CH3OH被氧化为羟甲基C H自由基（产生轴向信号）。据信电荷转移氧化还原反应是通过EDA [UO22 +，C
• Differential Coordination Demands in Fe versus Mn Water-Soluble Cationic Metalloporphyrins Translate into Remarkably Different Aqueous Redox Chemistry and Biology
  作者：Artak Tovmasyan、Tin Weitner、Huaxin Sheng、MiaoMiao Lu、Zrinka Rajic、David S. Warner、Ivan Spasojevic、Julio S. Reboucas、Ludmil Benov、Ines Batinic-Haberle

  DOI：10.1021/ic3012519

  日期：2013.5.20

  in large differences in the E1/2 values of MIIIP/MIIP redox couples. The presence of hydroxo ligand labilizes trans-axial water which results in higher reactivity of Fe relative to Mn center. The differences in the catalysis of O2•– dismutation (log kcat) between Fe and Mn porphyrins is modest, 2.5–5-fold, due to predominantly outer-sphere, with partial inner-sphere character of two reaction steps

  阳离子 Fe 和 Mn 吡啶基卟啉在大肠杆菌和小鼠研究中的不同生物学行为促使我们重新审视和比较它们的化学性质。为此，合成了一系列Fe(III)内消旋-四-N-烷基吡啶基卟啉的邻位和间位异构体，烷基是甲基到正辛基，并通过元素分析、紫外/可见光谱、质谱、亲脂性、轴向水的质子化平衡，金属中心还原电位，M III P/M II P 氧化还原对的E 1/2（M = Fe，Mn，P = 卟啉），k cat用于催化 O 2 •–歧化、对过氧化物驱动的卟啉氧化降解的稳定性（由 MP 催化抗坏血酸氧化产生）、影响 SOD 缺陷型大肠杆菌生长的能力以及对小鼠的毒性。金属位点的缺电子由卟啉配体调节，这使得 Fe(III) 卟啉比类似的 Mn(III) 卟啉酸 ≥5 个数量级，如轴向配位水的 p K a1所揭示。卟啉中 Mn 和 Fe 位点之间酸度的 5 log 单位差异转化为四阳离子 (OH)(H 2 O)FeP
• Pispisa, Basilio; Venanzi, Mariano; Palleschi, Antonio, Gazzetta Chimica Italiana, 1995, vol. 125, # 10, p. 445 - 452
  作者：Pispisa, Basilio、Venanzi, Mariano、Palleschi, Antonio

  DOI：——

  日期：——
• An ESR study of free-radical protonation equilibria in strongly acid media
  作者：H. F. Davis、H. J. McManus、Richard W. Fessenden

  DOI：10.1021/j100281a066

  日期：1986.11