Aminyl Radical Generation via Tandem Norrish Type I Photocleavage, β-Fragmentation: Independent Generation and Reactivity of the 2'-Deoxyadenosin- N6-yl Radical.

ABSTRACT: Formal hydrogen atom abstraction from the nitrogen-hydrogen bonds in purine nucleosides produces reactive intermediates that are important in nucleic acid oxidation. Herein we describe an approach for the independent generation of the purine radical resulting from hydrogen atom abstraction from the N6-amine of 2'-deoxyadenosine (dA•). The method involves sequential Norrish Type I photocleavage of a ketone (7b) and β-fragmentation of the initially formed alkyl radical (8b) to form dA• and acetone. The formation of dA• was followed by laser flash photolysis, which yields a transient with λ_max ≈ 340 nm and a broader weaker absorption centered at ∼560 nm. This transient grows in at ≥2 × 10⁵ s^-1; however, computations and reactivity data suggest that β-fragmenta

SUBMITTER: Zheng L 

PROVIDER: S-EPMC5494259 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature