ISSN:
1434-4475
Keywords:
2-Alkylidene-1,3-indandiones
;
Autoxidation
;
1-Hydroxy-2-vinylinden-3-ones
;
Photoenolisation
;
2-Vinyl-1,3-indandion-2-yl radicals
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The title compound,1, slowly decomposes in solution by autodixation, especially in daylight. The chemism of this photoinduced autoxidation has been investigated. Upon irradiation1 passes to the brick red isolable dienol2. The quantum yield is 0.3 at 313 nm in methanol. In solution an equilibrium is set up within several minutes between2 and the colorless deconjugated3. Unpolar or moderately polar solvents shift the equilibrium completely to3, whereas in highly polar solvents2 and3 coexist. In the dark the equilibrium1⇄2 (ca. 50∶1 in methanol) is established very slowly.3 upon irradiation reacts further to dimer8. 2 instantaneously reacts with oxygen. With high oxygen concentrations, hydroperoxide9 is formed, with lower ones dehydrodimer10, inter alia.9 and10 may further form12, 14, and15. These reactions, together with ESR spectroscopy, point to a central role of the free radical13 both in the autoxidation and in the reaction10→14. Basic catalysis sets up an equilibrium between1 and its dimer,17. The photoreaction1→2 has been investigated by sensitizing and quenching experiments.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00938736
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