Synthesis and Photoreaction of 5-Aikenyloxypsoralen Derivatives |
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Authors: | Elena Giménez-Arnau Jean-Pierre Lepoittevin |
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Institution: | Laboratoire de Dermatochimie associéau CNRS, UniversitéLouis Pasteur, Clinique Dermatologique, Strasbourg, France |
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Abstract: | Abstract— In order to investigate the intramolecular "quenching" of the photoexcitation of some 5-alkenyloxypsoralen derivatives, we have prepared model compounds in which a psoralen moiety was linked at position 5 to a terminal double bond via a polymethylenic chain of various length (n = 2-9). The isolation and characterization of photocycloadducts obtained for each compound after irradiation at 365 nm in a polar solvent was performed. The results on the photoreactivity of this series of compounds show that the 3,4-pyrone double bond of 5-alkoxypsoralens is the most reactive. Four kinds of intramolecular photocycloadducts between the 3,4-pyrone double bond and the chain unsaturation were obtained according to the length of the linking chain: cis-syn, trans-syn, cis-anti and trans-anti. Their structures were established by a combination of 1H and 13C NMR and fully assigned by lH NOE (nuclear Overhauser effect) and 1H-13C HMQC (heteronuclear multiquantum correlation) spectroscopies. No traces of 4',5' adducts were detected. |
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