Polymer Radicals - Free-Radical-Induced DNA Damage and Its Repair - page 190

The CO 2 yield considerably exceeds that of the acetylacetone-like product, and
although CO 2 is certainly also formed in other reactions (cf. the low molecular
weight model; Ulanski et al. 1996b), this observation may be taken as a hint that
the H-abstraction reaction does not proceed with neighboring groups only (via
a favorable six-membered transition state) but also with more distant sites. A
chain-type autoxidation has also been observed with poly(vinyl methyl ether)
and a related model compound (Janik et al. 2000a,b).
A polymer much closer to DNA is poly(U). With this polymer, base radicals
and base peroxyl radicals abstract an H-atom sugar moiety of the neighboring
or a close-by nucleotide [e.g., reaction (10); Deeble and von Sonntag 1984, 1986;
Deeble et al. 1986].

Compared to DNA, this H-transfer to the sugar moiety is especially favored in
poly(U) or poly(C) (Chap. 11.2) by the low C(2 ′ ) − H BDE induced by the OH group

in α -position (Chap. 6.5).