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Avraham E, Meyerstein D, Lerner A, Yardeni G, Pevzner S, Zilbermann I, Moisy P, Maimon E, Popivker I. Reactions of methyl, hydroxyl and peroxyl radicals with the DOTA chelating agent used in medical imaging. Free Radic Biol Med 2022; 180:134-142. [PMID: 34973364 DOI: 10.1016/j.freeradbiomed.2021.12.313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/13/2021] [Accepted: 12/27/2021] [Indexed: 12/30/2022]
Abstract
The mechanism of reaction of DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) with ·CH3, CH3O2· and ·OH radicals were studied. The radicals were formed in situ radiolytically. The methyl radicals react orders of magnitude slower with DOTA and with MIII(DOTA)- than the hydroxyl radicals. The various final products were identified and mechanisms for their formation are proposed. CH3O2· radicals do not react, or react too slowly to be observed, with DOTA and with MIII(DOTA)- as long as the central cation is not oxidized by the peroxyl radical. The results imply that synthesis of the MIII(DOTA)-(MIII = radioisotope) complexes in a water-organic solvent (ethanol or 2-propanol or acetonitrile) mixture is not only kinetically desired but the so formed complex also decreases the radiolytic decomposition of DOTA.
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Affiliation(s)
- Elad Avraham
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Dan Meyerstein
- Department of Chemical Sciences, The Radical Research Center and the Schlesinger Family, Center for Compact Accelerators, Radiation Sources and Application, Ariel University, Ariel, Israel; Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ana Lerner
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Israel Atomic Energy Commission, Tel Aviv, Israel
| | - Guy Yardeni
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Svetlana Pevzner
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Israel Zilbermann
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Philippe Moisy
- CEA, DES, ISEC, DMRC, Univ Montpellier, Marcoule, France
| | - Eric Maimon
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Inna Popivker
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel.
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Lerner A, Kornweitz H, Zilbermann I, Yardeni G, Saphier M, Bar Ziv R, Meyerstein D. Radicals in 'biologically relevant' concentrations behave differently: Uncovering new radical reactions following the reaction of hydroxyl radicals with DMSO. Free Radic Biol Med 2021; 162:555-560. [PMID: 33217506 DOI: 10.1016/j.freeradbiomed.2020.11.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/02/2020] [Accepted: 11/10/2020] [Indexed: 12/12/2022]
Abstract
Methyl radicals play key roles in various chemical and biological processes. Mechanistic studies of methyl radicals with their precursor, Dimethyl Sulfoxide (DMSO), were extensively studied. Though the involved mechanisms seemed to be clarified, essentially none of the studies have been performed at conditions relevant to both biological and catalytic systems, i.e. low steady state radical concentrations. A chain-like reaction, as an inverse function of the radicals concentrations ([•CH3]ss), increases the methyl radical yields. The nature of the additional products obtained differs from those commonly observed. Furthermore it is shown that methyl radicals abstract a methyl group from DMSO to yield ethane. Herein we report a novel mechanism relevant mainly at low steady state radical concentrations, which may change the understanding of certain reaction routes present in both biological systems and catalytic chemical systems. Thus the results point out that mechanistic studies have to be carried out at dose rates forming radicals at analogous concentrations to those present in the process of interest.
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Affiliation(s)
- Ana Lerner
- Chemistry Department, Ben-Gurion University, Beer-Sheva, Israel; Chemistry Department, Israel Atomic Energy Commission, Tel Aviv, Israel
| | - Haya Kornweitz
- Department of Chemical Sciences, The Center for Radical Reactions and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel, Israel
| | - Israel Zilbermann
- Chemistry Department, Ben-Gurion University, Beer-Sheva, Israel; Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Guy Yardeni
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Magal Saphier
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Ronen Bar Ziv
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Dan Meyerstein
- Chemistry Department, Ben-Gurion University, Beer-Sheva, Israel; Department of Chemical Sciences, The Center for Radical Reactions and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel, Israel.
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Mizrahi A, Maimon E, Cohen H, Zilbermann I. Reactions of carbonate radical anion with amino-carboxylate complexes of manganese(II) and iron(III). J COORD CHEM 2018. [DOI: 10.1080/00958972.2018.1496242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Amir Mizrahi
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
| | - Eric Maimon
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Haim Cohen
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Chemical Sciences Department and the Schlesinger Family Center for Compact Accelerators, Radiation Sources and Applications, Ariel University, Ariel, Israel
| | - Israel Zilbermann
- Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Mishra SK, Suryaprakash N. Study of H/D exchange rates to derive the strength of intramolecular hydrogen bonds in halo substituted organic building blocks: An NMR spectroscopic investigation. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.09.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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