- Characterization of 4-oxo-2-nonenal as a novel product of lipid peroxidation
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Fe (II)-mediated decomposition of 13-[S-(Z,E)]-9,11-hydroperoxyoctadecadienoic (hydroperoxy-linoleic) acid resulted in the formation of three α,β-unsaturated aldehydes. At low Fe (II) concentrations or at early time points after the addition of Fe(II), two major products were observed. The least polar product had chromatographic properties that were identical with those of 4-oxo-2-nonenal. Conversion of this product to its bis-oxime derivative with hydroxylamine hydrochloride resulted in two syn- and two anti-oxime isomers that had chromatographic and mass spectral properties identical with the properties of products derived from an authentic standard of 4-oxo-2-nonenal. This confirmed for the first time that 4-oxo-2-nonenal is a major product of the Fe(II)-mediated breakdown of lipid hydroperoxides. The more polar product had chromatographic properties that were similar to those of 4-hydroperoxy-2-nonenal. LC/MS analysis of its syn- and anti-oxime isomers confirmed this structural assignment. Thus, 4-hydroperoxy-2-nonenal is a previously unrecognized major product of lipid hydroperoxide decomposition. At high Fen concentrations and at longer incubation times, a third more polar product was observed with chromatographic properties that were identical to those of 4-hydroxy-2-nonenal. The syn- and anti-oxime isomers had chromatographic and mass spectral properties identical with the properties of products derived from an authentic standard of 4-hydroxy-2-nonenal. It appears that 4-hydroperoxy-2-nonenal is formed initially and that it is then converted to 4-hydroxy-2-nonenal in the presence of high Fe (II) concentrations or by extended incubations in the presence of low Fen concentrations. It is conceivable that some of the 4-hydroperoxy-2-nonenal is also converted to 4-oxo-2-nonenal. However, we cannot rule out the possibility that it is also formed by a concerted mechanism from a rearrangement product of 13-[S-(Z,E)]-9,11-hydroperoxyoctadecadienoic acid.
- Hwa Lee,Blair
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- Synthesis of (E)-4-Oxonon-2-enoic acid, a natural antibiotic produced by Streptomyces olivaceus
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(E)-4-Oxonon-2-enoic acid (1), a natural antibiotic produced by Streptomyces otivaceus, has been conveniently prepared in three steps starting from furan.
- Ballini,Bosica
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- In vitro synthesis of 1,N6-etheno-2′-deoxyadenosine and 1,N2-etheno-2′-deoxyguanosine by 2,4-dinitrophenol and 1,3-dinitropyrene in presence of a bacterial nitroreductase
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The formation of covalent nitro-PAH DNA adducts and nitro-PAH mediated oxidative lesions are two possible mechanisms for the initiation of nitro-PAH carcinogenesis. Sixty-minute incubation of 1,3-dinitropyrene (100 μM) or 1,4-dinitrophenol (100 μM) with a mixture of 150 μM NADH, 0.5 units of E. coli nitroreductase, 100 μM linoleic acid, 0.5 mM ferrous iron, and 100 μM 2′-deoxyadenosine (2′-dA) or 100 μM 2′-deoxyguanosine (2′-dG) were analyzed by liquid chromatography multistage mass spectrometry. Mixtures of 1,N6-etheno-2′-deoxyadenosine (εdA) plus 4-oxo-2-nonenal (4-ONE) and 1,N2-etheno-2′- deoxyguanosine (εdG) plus 4-ONE could be detected from 2′-dA and 2′-dG, respectively. Addition of 2% propanol inhibited the formation of etheno adducts. Analyses of disappearance kinetics of dA and dG showed that dG was more rapidly eliminated than does dA (t[1/2] = 23.3 min and 98.3 min for dG and dA, respectively). Curves of formation kinetics revealed that the peak of εdG was at 55.6 min while that of εdA was at 186.9 min. These peaks represented 1.43% and 1.25% of the original dG and dA, respectively. In both cases, the peaks were followed by rapid degradations of etheno adducts. The results, obtained in this system, do not allow any extrapolation to realistic cellular responses; nevertheless, these data questioned the validity of the use of unsubstituted etheno adducts as reliable oxidative stress and nitro-PAH exposure biomarkers.
- Chiron, Serge,Barbati, Stephane,De Meo, Michel,Botta, Alain
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- Independent synthesis, solution behavior, and studies on the mechanism of formation of a primary amine-derived fluorophore representing cross- linking of proteins by (E)-4-hydroxy-2-nonenal
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Lipid peroxidation in aging and degenerative disease results in the production of 4-hydroxy-2-alkenals that modify proteins and give rise to both protein cross-linking and fluorophore generation. Recent model studies demonstrated that the major ex/em 360/430 fluorophore formed from (E)-4- hydroxy-2-nonenal (HNE) or (E)-4-hydroxy-2-hexenal (HHE) and protein lysine- based amine is a 2-alkyl-2-hydroxy-1,2-dihydropyrrol-3-one iminium 1:2 cross- link (1), a structure that is further confirmed here using 15N-labeling, and which has pH stability characteristics the same as those of lipofuscin pigments isolated from human tissues. Fluorophore generation represents an overall four-electron oxidation, requires dioxygen, and is enhanced by the presence of Cu(II). The HNE-propylamine-derived fluorophore 1a was independently synthesized from either 3,4-dioxononanal (8) or (E)-4-oxo-2- nonenal (13), providing further evidence for its assigned structure and clues to how it forms from HNE. Mechanistic studies on HNE-derived fluorophore formation permit ruling out the initial reversible HNE-derived Schiff base Michael adduct (17) as an intermediate. In addition, the structurally related non-cross-link 2-pentyl-2-hydroxy-1,2-dihydropyrrol-3-one 9a that forms along with 1a from 8 does not form from HNE and does not serve as a precursor to 1a in the HNE-amine reaction system. A mechanism involving two 2e oxidations following initial Schiff base formation is proposed that is consistent with intermediates independently accessed from 8 and 13.
- Xu, Guozhang,Liu, Yahua,Sayre, Lawrence M.
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- Stereoselective Synthesis of cis-2-Ene-1,4-diones via Aerobic Oxidation of Substituted Furans Catalyzed by ABNO/HNO3
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We report a highly efficient and selective catalytic system, ABNO (9-azabicyclo-[3.3.1]nonane N-oxyl)/HNO3, for the aerobic oxidation of substituted furans to cis-2-ene-1,4-diones under mild reaction conditions using oxygen as the oxidant. The catalyst system is amenable to various substituted (mon-, di-, and tri-) furans and tolerates diverse functional groups, including cyano, nitro, naphthyl, ketone, ester, heterocycle, and even formyl groups. Based on the control and 18O-labeling experiments, the possible mechanism of the oxidation is proposed.
- Yang, Liqun,Wang, Jingyang,Wang, Yue,Li, Xiaotong,Liu, Wei,Zhang, Zhaoguo,Xie, Xiaomin
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p. 14311 - 14320
(2021/10/25)
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- Enantioselective Organocatalytic Cascade Approach to Different Classes of Benzofused Acetals
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A novel enantioselective organocatalytic strategy is presented for the synthesis of tetrahydrofurobenzofuran and methanobenzodioxepine natural product core structures. The strategy is based on a pair of divergent reaction pathways in which hydroxyarenes react with γ-keto-α,β-unsaturated aldehydes, catalyzed by a chiral secondary amine. One reaction pathway, which leads to chiral 5,5-fused acetals with two stereocenters—the tetrahydrofurobenzofuran scaffolds—proceeds in moderate yields and up to 96 % ee. The other reaction pathway provides 5,6-bridged methanobenzodioxepine scaffolds with three stereocenters in moderate to good yields and up to 95 % ee. The reaction is remarkable as it can proceed with catalyst loadings as low as 0.25 mol %, providing one of the highest known turnover numbers in iminium ion catalysis. Furthermore, the hemiacetal tetrahydrofurobenzofuran can undergo functionalizations including reduction, oxidation, and allylation. Finally, the effects involved in the substrate control for the divergent pathways, based on both experimental and computational studies, have been investigated. A model involving steric, electronic and stereoelectronic interactions is discussed to rationalize the observed selectivities.
- Paz, Bruno Matos,Klier, Lydia,N?sborg, Line,Lauridsen, Vibeke Henriette,Jensen, Frank,J?rgensen, Karl Anker
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supporting information
p. 16810 - 16818
(2016/11/16)
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- Synthesis of deuterium-labeled analogs of the lipid hydroperoxide-derived bifunctional electrophile 4-oxo-2(E)-nonenal
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Lipid hydroperoxides undergo homolytic decomposition into the bifunctional 4-hydroxy-2(E)-nonenal and 4-oxo-2(E)-nonenal (ONE). These bifunctional electrophiles are highly reactive and can readily modify intracellular molecules including glutathione (GSH), deoxyribonucleic acid (DNA) and proteins. Lipid hydroperoxide-derived bifunctional electrophiles are thought to contribute to the pathogenesis of a number of diseases. ONE is an α,β-unsaturated aldehyde that can react in multiple ways and with glutathione, proteins and DNA. Heavy isotope-labeled analogs of ONE are not readily available for conducting mechanistic studies or for use as internal standards in mass spectrometry (MS)-based assays. An efficient one-step cost-effective method has been developed for the preparation of C-9 deuterium-labeled ONE. In addition, a method for specific deuterium labeling of ONE at C-2, C-3 or both C-2 and C-3 has been developed. This latter method involved the selective reduction of an intermediate alkyne either by lithium aluminum hydride or lithium aluminum deuteride and quenching with water or deuterium oxide. The availability of these heavy isotope analogs will be useful as internal standards for quantitative studies employing MS and for conducting mechanistic studies of complex interactions between ONE and DNA bases as well as between ONE and proximal amino acid residues in peptides and proteins. Copyright
- Arora, Jasbir S.,Oe, Tomoyuki,Blair, Ian A.
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experimental part
p. 247 - 251
(2012/02/03)
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- SUBSTITUTED CYCLOALKENE DERIVATIVE
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[Object] To provide a substituted cycloalkene derivative having an action to supress intracellular signal transduction or cell activation induced by endotoxin and to suppress cell responses due to the intracellular signal transduction and cell activation such as an excess generation of inflammatory mediators such as TNF-α, pharmacologically acceptable salts therefor, a medicament containing them as an active ingredient, a preparation method therefor, and a medicament containing the aforementioned substituted cycloalkene derivative as an active ingredient which is superior in prophylaxis and/or treatment of diseases such as sepsis (septic shock, disseminated intravascular coagulation, multiple organ failure and the like), that are associated with intracellular signal transduction or cell activation induced by endotoxin and to cell responses to the intracellular signal transduction and cell activation. [Solution] A compound represented by the general formula (I): {wherein X and Y represent a group in which X and Y together with a carbon atom to which they are bound form ring A (the ring is 3- to 7-membered heterocyclyl ring or 3- to 7-membered cycloalkyl ring), each represents a hydrogen atom, or X and Y together represent a substituent of ring B. 1 and m, independently from each other, represent an integer of 0 to 3, and 1 + m is 1 to 3. R1 is an aliphatic hydrocarbon group and the like which may be substituted with a group selected from Substituent group β and Substituent group γ. n represents an integer of 0 to 3. R2 is a C1-C6 alkyl group and the like which may be substituted with a group selected from a hydrogen atom and Substituent group β. R3 is a phenyl group, 5- to 6-membered heteroaryl group and the like which may be substituted with a group selected from Substituent group ε. R5 is a C1-C6 alkyl group and the like which may be substituted with a group selected from a hydrogen atom and Substituent group β. Provided that in the case where R3 is a phenyl group which may be substituted with a group selected from Substituent group ε, X and Y represent a group in which X and Y together with a carbon atom to which they are bound form ring A, or X and Y together represent a substituent of ring B.
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Page/Page column 191
(2008/12/06)
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- Asymmetric synthesis of aliphatic α-amino and γ-hydroxy α-amino acids and introduction of a template for crystallization-induced asymmetric transformation
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The asymmetric synthesis of aliphatic α-amino and γ-hydroxy α-amino acids is described. The key step is an aza-Michael addition controlled by crystallization-induced asymmetric transformation (CIAT), affording excellent diastereomeric ratios (dr ≥96:4). C
- Jakubec, Pavol,Berkes, Dusan,Kolarovic, Andrej,Povazanec, Frantisek
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p. 4032 - 4040
(2008/03/11)
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- Selenium in Organic Synthesis: A Novel Route to 1-Phenylselenobutadienes and 1,4-Dicarbonyl Compounds
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Two approaches to 1-phenylseleno-1,3-butadienes 5 are reported, via phenylselenoalkenylidene phosphoranes and phenylselenoalkenals, respectively. 1,4-Dicarbonyl compounds are prepared from the 1-phenylselenobutadienes or from the phenylselenoalkenals.
- Comasseto, J. V.,Brandt, C. A.
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p. 146 - 149
(2007/10/02)
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- APPLICATION OF FURAN OXIDATIONS IN SYNTHESIS: TOTAL SYNTHESIS OF (+/-)-COROLIC ACID
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As a general synthesis approach to compounds containing the cis-trans allylhydroxy functionality ( subunit A), an appropriately substituted furan nucleus is oxidatively cleaved to provide an unsaturated 1,4-dicarbonyl moiety suitably disposed for further elaboration.The total synthesis of (+/-)-coriolic acid demonstrates the utility of the approach.
- Gunn, Bruce P.
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p. 3061 - 3067
(2007/10/02)
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