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A Combined Experimental and Theoretical Approach to the Photogeneration of 5,6-Dihydropyrimidin-5-yl Radicals in Nonaqueous Media
- Source :
- RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia, instname
- Publication Year :
- 2016
- Publisher :
- American Chemical Society (ACS), 2016.
-
Abstract
- The chemical fate of radical intermediates is relevant to understand the biological effects of radiation and to explain formation of DNA lesions. A direct approach to selectively generate the putative reactive intermediates is based on the irradiation of photolabile precursors. But, to date, radical formation and reactivity have only been studied in aqueous media, which do not completely mimic the micro environment provided by the DNA structure and its complexes with proteins. Thus, it is also important to evaluate the photogeneration of nucleoside-based radicals in nonaqueous media. The attention here is focused on the independent generation of 5,6-dihydropyrimidin-5-yl radicals in organic solvent through the synthesis of new lipophilic tert-butyl ketone precursors. Formation of 5,6-dihydro-2'-deoxyuridin-S-yl and 5,6-dihydrothymidin-5-yl radicals has first been confirmed by using a new nitroxide-derived profluorescent radical trap. Further evidence has been obtained by nanosecond laser flash photolysis through detection of long-lived transients. Finally, the experimental data are corroborated by multiconfigurational ab initio CASPT2//CASSCF methodology.<br />Spanish Government (CTQ2012-32621, CTQ2015-70164-P, CTQ2014-58624-P, RIRAAF RETICS RD12/0013/0009, Severo Ochoa program/SEV-2012-0267, Maria de Maetzu program/MDM-2015-0538, BES-2011-048326 and BES-2013-066566, JCI-2012-13431) and Generalitat Valenciana (Prometeo 11/2013/005 and GV2015-057) are gratefully acknowledged. Dr. M. Luisa Marin is also acknowledged for her help during laser flash photolysis experiments.
- Subjects :
- Ketone
THYMIDINE
DNA damage
Radical
Reactive intermediate
010402 general chemistry
Photochemistry
Hydrogen atom abstraction
01 natural sciences
QUIMICA ORGANICA
AQUEOUS-SOLUTIONS
QUIMICA ANALITICA
STRAND SCISSION
Reactivity (chemistry)
REPAIR
chemistry.chemical_classification
Aqueous solution
010405 organic chemistry
Organic Chemistry
INDEPENDENT GENERATION
0104 chemical sciences
5,6-DIHYDROTHYMID-5-YL
DNA-DAMAGE
chemistry
2ND-ORDER PERTURBATION-THEORY
RADIATION
Flash photolysis
HYDROGEN-ATOM ABSTRACTION
Subjects
Details
- ISSN :
- 15206904 and 00223263
- Volume :
- 81
- Database :
- OpenAIRE
- Journal :
- The Journal of Organic Chemistry
- Accession number :
- edsair.doi.dedup.....5fc23e8c5777095b1c97497b414fb5d1