<Review>A Novel Heterocyclic N-Oxide, Pyrimido[5,4-g]pteridinetetrone 5-Oxide, with Multifunctional Phot-oxidative Properties. : Efficient Agents for Photo-oxygenation and -dehydrogenation, and for Photochemical Generation of Hydroxyl Radicals.

During our search for heterocyclic N-oxides possessing high photo-oxidation capacity, pyrimido[5,4-g]pteridinetetrone 5-0xides were discovered to fulfill this role. Chemical and physico-chemical studies clearly indicated that the N-oxides behave as an electron acceptor to cause efficiently photo-oxygenation, photo-dehydrogenation and photochemical generation of hy-droxyl radicals, depending on the nature of the substrates and solvents employed. Thus, the N-oxides behave like oxygen under photochemical conditions and their multi-photooxidative functions mimic formally those of iron oxenoid. In this review, synthesis, photochemical properties and application of the novel N-oxides are described and discussed in the light of impetus for future investigation