TY - JOUR
T1 - Development of novel nitroxyl radicals for controlling reactivity with ascorbic acid
AU - Kinoshita, Yuichi
AU - Yamada, Ken Ichi
AU - Yamasaki, Toshihide
AU - Sadasue, Hiromi
AU - Sakai, Kiyoshi
AU - Utsumi, Hideo
N1 - Funding Information:
This work was partially supported by the Development of System and Technology for Advanced Measurement and Analysis grant from the Japan Science and Technology Agency and the Grant-in-Aid for Young Scientists (A) (No. 19689002) from the Japan Society for the Promotion of Science.
PY - 2009
Y1 - 2009
N2 - Piperidine and pyrrolidine nitroxyl radicals (nitroxide) contain unpaired electrons and have been widely recognized as antioxidants, contrast agents, spin probes, radiation protective agents and polymerization mediators. Nitroxyl radicals can react with free radicals and reductants and their reactivities depend on the basic structure of the nitroxyl radicals themselves. However, reductants easily reduce these radicals and they lose their paramagnetic nature and function. Therefore, the aim of this study was to develop various functional nitroxyl radicals, particularly focusing on stability towards AsA through the improvement of the synthetic route for a series of 2,6-substituted nitroxyl radicals. Tetraethyl-substituted piperidine nitroxyl radical 8 exhibited resistance to AsA reduction and 2,6-dispiro-4′,4″-dipyrane-piperidin-4-one-N-oxyl 5 had a second-order rate constant 10-times greater than those of hydroxyl-TEMPO and oxo-TEMPO. The 2,6-substituted compound offers various reactivities towards AsA and the possibility to be used as a new antioxidant, contrast agent and radical polymerizer.
AB - Piperidine and pyrrolidine nitroxyl radicals (nitroxide) contain unpaired electrons and have been widely recognized as antioxidants, contrast agents, spin probes, radiation protective agents and polymerization mediators. Nitroxyl radicals can react with free radicals and reductants and their reactivities depend on the basic structure of the nitroxyl radicals themselves. However, reductants easily reduce these radicals and they lose their paramagnetic nature and function. Therefore, the aim of this study was to develop various functional nitroxyl radicals, particularly focusing on stability towards AsA through the improvement of the synthetic route for a series of 2,6-substituted nitroxyl radicals. Tetraethyl-substituted piperidine nitroxyl radical 8 exhibited resistance to AsA reduction and 2,6-dispiro-4′,4″-dipyrane-piperidin-4-one-N-oxyl 5 had a second-order rate constant 10-times greater than those of hydroxyl-TEMPO and oxo-TEMPO. The 2,6-substituted compound offers various reactivities towards AsA and the possibility to be used as a new antioxidant, contrast agent and radical polymerizer.
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U2 - 10.1080/10715760902914575
DO - 10.1080/10715760902914575
M3 - Article
C2 - 19384748
AN - SCOPUS:67650928120
SN - 1071-5762
VL - 43
SP - 565
EP - 571
JO - Free Radical Research
JF - Free Radical Research
IS - 6
ER -