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

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• 作者：Celewicz ; Lech
• 关键词：5-Fluorouracil ; 5-Fluoro-2&prime ; -deoxyuridine ; N^α ; -acetyl-l-tryptophan N-ethylamide ; Photocoupling reactions
• 刊名：Journal of Photochemistry and Photobiology B: Biology
• 出版年：1998
• 出版时间：April, 1998
• 年：1998
• 卷：43
• 期：1
• 页码：66-72
• 全文大小：572 K

文摘

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-[1-(2-deoxy-β-d-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.