Synthesis and spin-trapping properties of a new spirolactonyl nitrone.
Spin trapping using electron paramagnetic resonance (EPR) spectroscopy is commonly employed for the identification of transient radicals in chemical and biological systems. A spirolactonyl-nitrone with rigid H-bond acceptor, 7-oxa-1-azaspiro[4.4]non-1-en-6-one 1-oxide, CPCOMPO, has been synthesized and characterized, and its spin-trapping properties were investigated. The rate of formation of CPCOMPO-O2H was determined using competition kinetics between the superoxide/hydroperoxyl radical (O2*-/HO2*) trapping by CPCOMPO and the spontaneous dismutation of this radical in aqueous media. The rate constant of 60 M-1.s-1 is the highest rate constant thus far observed at neutral pH for any nitrones using the kinetic method employed. Decay kinetics were also experimentally investigated for CPCOMPO-O2H. The effect of rigid H-bond acceptor on the stability of the CPCOMPO-O2H were computationally rationalized and compared to that of EMPO-O2H, which has flexible H-bond acceptor, and results show the need of a "loose" H-bond acceptor for improved adduct stability.
Han
Yongbin
Y
Department of Pharmacology, The Ohio State University, Columbus, OH 43210, USA.
Tuccio
Beatrice
B
Lauricella
Robert
R
Rockenbauer
Antal
A
Zweier
Jay L
JL
Villamena
Frederick A
FA
D000838:Anions / Q000737:chemistry; D003198:Computer Simulation; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D006860:Hydrogen Bonding; D007700:Kinetics; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D009589:Nitrogen Oxides / Q000138:chemical synthesis* / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000737:chemistry; D019097:Spin Trapping / Q000379:methods*; D013148:Spironolactone / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism
D000838:Anions; D009589:Nitrogen Oxides; D017382:Reactive Oxygen Species; C015388:nitrones; D013148:Spironolactone