22574-12-5Relevant articles and documents
N-Aroyloxy-2-thiopyridones as efficient oxygen-radical generators: Novel time-controlled DNA photocleaving reagents
Theodorakis, Emmanuel A.,Wilcoxen, Keith M.
, p. 1927 - 1928 (1996)
N-Aroyloxy-2-thiopyridones efficiently cleave DNA upon visible light illumination via the formation of aroyloxyl radicals.
Photochemistry of N-hydroxypyridine-2-thione derivatives: Involvement of the 2-pyridylthiyl radical in the radical chain reaction mechanism
Aveline, Béatrice M.,Kochevar, Irene E.,Redmond, Robert W.
, p. 9699 - 9708 (2007/10/02)
The primary and subsequent photochemistry of four N-hydroxypyridine-2-thione esters has been investigated by laser flash photolysis (λexc = 355 nm). A simple, high-yield synthetic method is given for their preparation with high purity. UV irradiation of these ester compounds was shown to lead specifically to the formation of benzyl, diphenylmethyl, tert-butyl, and benzoyloxyl radicals in addition to the 2-pyridylthiyl radical. In all cases, the initial photoinduced nitrogen-oxygen bond cleavage was found to occur in high quantum yield (ΦN-O ≈ 0.5). The radical species generated by this process (2-pyridylthiyl radical and carbon-centered or oxygen-centered radicals) were characterized and their reactivity toward several radical scavengers has been studied. An efficient delayed depletion of the N-hydroxypyridine-2-thione esters was also observed, leading to overall bleaching quantum yields, ΦBl, close to unity. We have demonstrated that the delayed consumption of ground-state ester was due to the reaction of the 2-pyridylthiyl radical with its precursor, occurring with a rate constant, kr, of 3-4 × 109 M-1 s-1. This reaction, hitherto never proposed, leads to the formation of 2,2′-dipyridyl disulfide and further release of propagating radicals.
