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Thymidine‐Psoralen Photoaddition: Stereoselective Formation of A trans‐syn Pyrone Adduct
Author(s) -
Décout JeanLuc,
Guendouz Amine,
Lhomme Jean
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.tb02423.x
Subject(s) - psoralen , thymidine , adduct , pyrone , chemistry , thymine , intramolecular force , stereochemistry , regioselectivity , stereoselectivity , derivative (finance) , dna , biochemistry , organic chemistry , financial economics , economics , catalysis
To study the photoreactions between thymidine and psoralen and to devise a synthetic route to prepare thymidine‐5‐methoxypsoralen adducts, we have synthesized a compound in which thymidine is linked to a 5‐methoxypsoralen derivative by a short flexible chain located to allow only the formation of syn intramolecular [2+2] cycloadducts. Irradiation at 365 nm carried out at usual concentrations (10 −2 ‐10 −3 M ) resulted in a regioselective dimerization involving the 3,4 double bonds. Extreme dilution ( c 5 × 10 6 M ) was necessary to observe the intramolecular photoaddition, which produces exclusively the 3,4‐ trans‐syn adduct. These results are compared to those obtained previously with similar heterodimers that lead exclusively to the 3,4‐ cis‐anti thymine or thymidine‐psoralen adduct on exposure to near UV light.