606-06-4Relevant academic research and scientific papers
New efficient synthesis of ubiquinones
Bovicelli, Paolo,Borioni, Giorgio,Fabbrini, Danilo,Barontini, Maurizio
, p. 391 - 400 (2008/04/01)
A strategy for the ecofriendly and high-yielding synthesis of ubiquinones starting from simple materials and using mild conditions is reported. CoQ1, CoQ2, CoQ3, and CoQ9 were prepared. Copyright Taylor & Francis Group, LLC.
Radical-scavenging polyphenols: New strategies for their synthesis
Bovicelli, Paolo
, p. 1703 - 1710 (2008/03/11)
New strategies for the synthesis of polyphenols, compounds with antioxidant properties contained in every kind of plants, are discussed. Syntheses of different classes of polyphenols, namely ubiquinones, present in many natural systems in which electron-transfer mechanisms are involved, hydroxytyrosol, one of the main components of the phenol fraction in olives, and flavonoids, widespread in the plant kingdom, were approached by simple and environmentally sustainable methods.
Synthesis and spectroscopic characterization of [1′-14C]ubiquinone-2, [1′-14C]-5-demethoxy-5-hydroxyubiquinone-2, and [1′-14C]-5-demethoxyubiquinone-2
Van Der Klei, Anita,De Jong, Robertus L. P.,Lugtenburg, Johan,Tielens, Aloysius G. M.
, p. 3015 - 3023 (2007/10/03)
[1′-14C]Ubiquinone-2, [1′-14C]-5-demethoxy-5-hydroxyubiquinone-2, and [1′-14C]-5-demethoxyubiquinone-2 have been synthesised from [1-14C]acetic acid. A common feature of these benzoquinones is the isoprenoid chain, and the 14C-label has therefore been incorporated in this isoprenoid. The coupling of the different quinone head groups and the isoprenoid chain is the last step in the total synthesis, to prevent unnecessary loss of the labelled material during synthesis. The products have been characterised by mass spectrometry, 1H NMR and 13C NMR.
NADPH and ferredoxin:NADP+ oxidoreductase-dependent reduction of quinones and their reoxidation
Bojko, Monika,Wieckowski, Stanislaw
, p. 203 - 208 (2007/10/03)
Molecular oxygen uptake was initiated by adding NADPH (1 mM) to the buffered medium containing 0.6 μM spinach ferredoxin:NADP+ oxidoreductase and 20 μM quinone (plastoquinone-2, decyl-plastoquinone, decyl-ubiquinone, or duroquinone). At pH 7.7 the rate of oxygen uptake was 2- to 12-fold higher during an initial phase (V1) than in a subsequent phase (V2). Except for duroquinone, the initial rate of oxygen consumption was ca. 2.7-fold higher in alkaline than in acidic medium. Ferredoxin was not essential, although it stimulated the reaction investigated. Oxygen uptake was not detectable with plastoquinone-9 or α-tocoquinone. The possible mechanisms of the NADPH and ferredoxin:NADP oxidoreductase dependent reduction of some quinones and their reoxidation are discussed.
Design, synthesis, and photochemical properties of a photoreleasable ubiquinol-2: A novel compound for studying rapid electron-transfer kinetics in ubiquinol-oxidizing enzymes
Wang, Guangyang
, p. 1657 - 1664 (2007/10/03)
The design and multistep convergent synthesis of the novel photoactive ubiquinol-benzoin adduct 1a,b has been accomplished. Optical spectra of the steady-state photolysis reactions showed a smooth conversion from 1a,b to 5,7-dimethoxy-2-phenylbenzofuran (13) and ubiquinol-2 with an isobestic point at 258 nm. HPLC analysis of the photoproducts was also consistent with the clean formation of the desired ubiquinol-2 (3) and the expected 5,7-dimethoxy-2-phenylbenzofuran (2). Transient photolysis at 355 nm was consistent with a rapid photolysis rate that exceeded the instrument response time (> 106 s-1). Accordingly, the study of rapid electron-transfer events in ubiquinol oxidizing enzymes is now feasible. Furthermore, the synthetic methods developed herein will be of general application for the facile synthesis of a variety of photoreleasable substrates for studying rapid kinetic events in enzymatic reactions.
Synthesis of crown ethers related to ubiquinones
Merz,Rauschel
, p. 797 - 802 (2007/10/02)
Crown ethers in which the two methoxy groups of ubiquinone-0 (2,3-dimethoxy-5-methyl-1,4-benzoquinone) are replaced by oligoethylene glycol bridges have been obtained in five straightforward steps in 35-40% overall yield from 5-methylpyrogallol. A Fremy salt oxidation of a phenolic precursor is used in the final step. The further elaboration of crown ether analogues of ubiquinone-2 was achieved by enol geranylation of cyclopentadiene adducts of the former quinones and subsequent retro-Diels-Alder reaction. The Claisen rearrangement of 2,2-dimethoxy-5-methylphenyl allyl ethers and related crown ethers affords ortho- and para-allyl-substituted phenols (3:1) that are oxidized to give bisnorubiquinone derivatives and their ortho-quinone isomers. All new compounds are characterized by high resolution NMR and mass spectrometry.
Total Synthesis of Linear Polyprenoids. 2. Improved preparation of the Aromatic Nucleus of Ubiquinone
Keinan, Ehud,Eren, Doron
, p. 3872 - 3875 (2007/10/02)
Highly efficient copper-catalyzed polymethoxylation of tribromocresol is the key process in a three-step, practical approach to obtain ubiquinone 0 from p-cresol.Short syntheses of several ubiquinones were achieved via direct, copper-mediated coupling of 2-lithio-3,4,5,6-tetramethoxytoluene to the appropriate polyprenyl bromide.
REGIOSELECTIVE POLYPRENYL REARRANGEMENT OF POLYPRENYL 2,3,4,5-TETRASUBSTITUTED PHENYL ETHERS PROMOTED BY BORON TRIFLUORIDE
Yoshizawa, Toyokichi,Toyofuku, Hatsunori,Tachibana, Koichi,Kuroda, Toshio
, p. 1131 - 1134 (2007/10/02)
4-Acetoxy-6-polyprenyl-2,3,5-trimethylphenols or 2,3-dimethoxy-5-methyl-6-polyprenylhydroquinones were obtained selectively by the BF3*OEt2 catalyzed polyprenyl rearrangement of polyprenyl 4-acetoxy-2,3,5-trimethylphenyl ethers or polyprenyl 2,3-dimethoxy-4-hydroxy-5-methylphenyl ethers.
