Study on the Photoinduced Nitric-Oxide-Releasing Ability of 4-Alkoxy Furoxans
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Nitric oxide (NO) has a range of biological activities in living systems. Because NO is a gaseous and short-lived molecule, the development of methods to enable a temporally and spatially resolved NO supply has been a challenging task. Herein, 3-aryl-4-alkoxy furoxan is revealed as a potent photoinduced NO donor. Whilst negligible levels of NO release were observed under ambient fluorescent light, a significant amount of NO was released under UV irradiation (λ=300–400 nm). A thiol mediator that contains a pendant amino group was found to be indispensable for NO release from aryl alkoxy furoxans. Analysis of the NO-releasing mechanism of aryl alkoxy furoxan revealed that the main coproduct was the corresponding aryl nitrile, which was derived from fragmentation of the furoxan ring. Based on these results, we have proposed a plausible mechanism for photoinduced NO release, in which the key steps are nucleophilic attack of the thiol at the 3-position of the furoxan, thereby leading to fragmentation of the furoxan ring, and the formation of a tetrahydrothiazole that contains a C‐nitroso group. A comparison of fluorofuroxan and alkoxy furoxan is also discussed.
- Asian Journal of Organic Chemistry
Asian Journal of Organic Chemistry 6(5), 619-626, 2017-05