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

✍ Scribed by Lech Celewicz

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 765 KB
• Volume: 43
• Category: Article
• ISSN: 1011-1344
• DOI: 10.1016/s1011-1344(98)00090-6

✦ Synopsis

Irradiation of 5-fluorouracil ( 1) and S-fluoro-2'.deoxyuridine (2) with R;" -acetyl-t.-tryptophan N-ethylamlde (5) in aqueous buffered ( pH 7) solutions led to N"-acetyl-3.( uracil-5-yl jtryptophan N-ethylamide (6) and N"-acetyl-2-l I-( ?-deoxy-~-I,-c~r?tC;,r-o-pentofuranosyl)uracil-5-y] 1 tryptophan N-ethylamide (7), respectively, as the main photoproducts. In addition. compounds 6 and 7 u ere synthesized by photochemical coupling of 5-bromouracil (3) and %bromo--7'-deoxyuridine (4). respectively, with 5. The formation ot cl-o:,+links hetween S-fluorouracil-substituted nucleic acids and tryptophan-containing proteins can be detected by Ruorexcence charactznstic of the uracil-tryptophan tluorophore. The mechanism proposed for the formation of photoproducts 6 and 7 involves electrophilic attack of the 5-ul-acilyl cation on the indole ring of 5.