BETA-PHOSPHORYLATED NITROXIDES IN THE PYRROLIDINE SERIES - REDUCTION BY ASCORBATE

Reduction-resistant nitroxides are particularly interesting for biomed ical applications. beta-Phosphorylated pyrrolidinyl nitroxides, a new series of stable pyrrolidinoxyl radicals prepared in our laboratory, w ere tested toward ascorbate reduction in phosphate buffer at pH 7.4. T he kinetics of decay were monitored by ESR and compared to those of tw o reference nitroxides, PCA and Proxyl. The introduction of a beta-pho sphoryl group on a pyrrolidinoxyl structure resulted in a moderate inc rease of the reduction rate constant. However, inside the phosphorylat ed series, slight structural modifications can induce significant chan ges in the rate constants. Copyright (C) 1997 Elsevier Science Inc.