N6-Substituent Effect on the Photooxidation of 2',3'-O-Isopropylideneadenosines with a Pyrimidopteridinetetraone N-Oxide. Chemical Evidence for the Generation and Reactivity of Adenosyl Cation Radicals

DOI: 10.1039/P19920001801

Source and publish data:

Journal of the Chemical Society. Perkin transactions I p. 1801 - 1806 (1992)

Update date:2022-08-03

Topics:

Authors:

Sako, Magoichi

Makino, Toru

Kitada, Yukio

Hirota, Kosaku

Maki, Yoshifumi

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Article abstract of DOI:10.1039/P19920001801

A comparative study on the photooxidation of 2',3'-O-isopropylideneadenosine 1a and its N⁶-benzoyl, N-⁶-monomethyl, and N⁶,N⁶-dimethyl derivatives, 1b-d, with a pyrimido<5,4-g>pteridinetetraone N-oxide (PPO) was carried out.The ease of photooxidative consumption of the adenosines by the PPO is in the order 1d > 1c > 1a > 1b, which is parallel to their oxidation-peak potentials.Although substrates 1a and 1b underwent oxidative intramolecular cyclisation to the corresponding 5'-O,8-cycloadenosines, 2a and 2b, even in low yield, substrates 1c and 1d were exclusively oxidised at the N⁶-methyl group to give the corresponding N⁶-formyl derivatives, 3 and 4, together with minor amounts of demethylated products, 1a and 1c.The present observations provide chemical evidence for the generation and reactivity of adenosyl cation radicals.