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Synthesis and Photoreaction of 5‐Aikenyloxypsoralen Derivatives
Author(s) -
GiménezArnau Elena,
Lepoittevin JeanPierre
Publication year - 1996
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1996.tb03010.x
Subject(s) - double bond , chemistry , degree of unsaturation , intramolecular force , heteronuclear molecule , pyrone , moiety , stereochemistry , adduct , nuclear overhauser effect , photochemistry , nuclear magnetic resonance spectroscopy , organic chemistry
— 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 1 H and 13 C NMR and fully assigned by l H NOE (nuclear Overhauser effect) and 1 H‐ 13 C HMQC (heteronuclear multiquantum correlation) spectroscopies. No traces of 4′,5′ adducts were detected.