Synthesis of C5-C6 Derivatives of 1,3-Dimethyl-5-Fluorouracil and 5-Fluorouracil. Screening for Antiviral Activity

5-Chloro-5-fluoro-6-alkoxypyrimidines were synthesized via Cl2 chlorination of 5-fluorouracil and 1,3-dimethyl-5-fluorouracil in various alcohols and were screened for antiviral activity. High antiviral activity was found for 5-chloro-5-fluoro-6-hydroxy-5,6-dihydrouracil against RS virus and human flu viruses A/H3N2 and A/H1N1pdm09.