Abstract— 1,2‐bis(4‐Hydroxyphenyl)‐3,4‐dihydro‐6‐hydroxynaphthalene (6) is a non‐steroidal ligand for the estrogen receptor that displays photofluorogenic properties. It binds to the receptor with an affinity greater than that of estradiol (150%), and it is esentially non‐fluorescent. However, upon brief UV irradiation in protic media it is converted efficiently to an aryl tetraenedione system (8) that is highly fluorescent, but has low affinity for the receptor (0.35%). The aryltetraenedione has a complex electronic spectrum, with absorbance (and fluorescence excitation) bands extending beyond 450 nm. Both the maxima (εmax) and the intensity (φf of the fluorescence emission of the aryl tetraenedione are solvent dependent. The tetraenedione (8) is structurally related to a tetraenedione (13) obtained by photocyclization of diethylstilbestrol(l0); since tetraenedione 13 is essentially non‐fluorescent, it appears that the aryl dienone chromophore in 8 is responsible for its fluorescence. Photolysis of 6 in non‐protic media results in a direct photocyclization‐oxidation to benzodihydrochrysene system 9 that is unstable and has less desirable fluorescent properties. The formation of 8 from 6 in protic media (as contrasted to the formation of 9 in non‐protic media) is thought to arise from the competition that operates on the primary photocyclization product, dihydrophenanthrene (7): In protic media, ketonization proceeds more rapidly than oxidation (aromatization), while in aprotic media, oxidation is more rapid. This photofluorogenic ligand for the estrogen receptor should enable interesting fluorescence binding studies with the estrogen receptor to be performed.
|Original language||English (US)|
|Number of pages||6|
|Journal||Photochemistry and Photobiology|
|State||Published - Feb 1986|
ASJC Scopus subject areas
- Physical and Theoretical Chemistry