Photochemical reactions of 5-fluorouracil and 5-fluoro-2′-deoxyuridine with N α-acetyl- L-tryptophan N-ethylamide in aqueous solution

Irradiation of 5-fluorouracil ( 1) and 5-fluoro-2′-deoxyuridine ( 2) with N α-acetyl- L-tryptophan N-ethylamide ( 5) in aqueous buffered (pH 7) solutions led to N α-acetyl-2-(uracil-5-yl) tryptophan N-ethylamide ( 6) and N α-acetyl-2-[l-(2-deoxy- β-l) erythro-pentofuranosyl)uracil-5-yl] tryptophan N...

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Bibliographic Details
Published in:Journal of photochemistry and photobiology. B, Biology Biology, 1998-04, Vol.43 (1), p.66-72
Main Author: Celewicz, Lech
Format: Article
Language:English
Subjects:
5-Fluoro-2′-deoxyuridine
5-Fluorouracil
N-ethylamide
Nα-acetyl-1-tryptophan
Photocoupling reactions
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Summary:Irradiation of 5-fluorouracil ( 1) and 5-fluoro-2′-deoxyuridine ( 2) with N α-acetyl- L-tryptophan N-ethylamide ( 5) in aqueous buffered (pH 7) solutions led to N α-acetyl-2-(uracil-5-yl) tryptophan N-ethylamide ( 6) and N α-acetyl-2-[l-(2-deoxy- β-l) erythro-pentofuranosyl)uracil-5-yl] tryptophan N-ethylamide ( 7), respectively, as the main photoproducts. In addition, compounds 6 and 7 were synthesized by photochemical coupling of 5-bromouracil ( 3) and 5-bromo-2′-deoxyuridine ( 4), respectively, with 5. The formation of cross-links between 5-fluorouracil-substituted nucleic acids and tryptophan-containing proteins can be detected by fluorescence characteristic of the uracil-tryptophan fluorophore. The mechanism proposed for the formation of photoproducts 6 and 7 involves electrophilic attack of the 5-uracilyl cation on the indole ring of 5.
ISSN:1011-1344
1873-2682
DOI:10.1016/S1011-1344(98)00090-6