Evaluation of N-hydroxy-2-thiopyridone as a nonmetal dependent source of the hydroxyl radical (HO·) in aqueous systems
✍ Scribed by Kathleen M. Hess; Thomas A. Dix
- Book ID
- 102988838
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 679 KB
- Volume
- 206
- Category
- Article
- ISSN
- 0003-2697
No coin nor oath required. For personal study only.
✦ Synopsis
N-hydroxy-2-thiopyridone (1), an established source of the hydroxyl radical (HO., Boivin, J., Crepon, E., and Zard, S. Z. (1990) Tetrahedron Lett. 31, 6869-6872), produced HO. under conditions directly applicable to biological studies. Generation of HO. by subjecting 1 to irradiation with visible light was monitored in the following "HO." assays: deoxyribose degradation, addition to dimethyl sulfoxide, and hydroxylation of salicylate and phenol. All four assays demonstrated the production of HO. from 1 (added as a sodium salt) under mild conditions in aqueous buffer systems. An improved analysis method was developed for the phenol assay. A time course analysis demonstrated that a flux of HO. is generated from 1 throughout the irradiation period, in contrast to the classical Fenton reaction of H2O2 with a transition metal in which a burst of HO. is generated in a short time period. While a thiyl radical is generated from 1 concurrent with HO. generation, this species does not contribute to, or interfere with, any of the HO. assays, suggesting that it is weakly reactive in aqueous buffers. Thus, irradiation of 1 can be used as an alternative, complementary, approach for the unequivocal generation of the biologically significant and reactive HO..