Abstract: | A series of novel 1‐(2′‐alkyl(or phenyl)thioethoxy)methyl‐5‐fluorouracils ( 6 ) were synthesized in three steps from 5‐fluorouracil. They were oxidized into sulfoxide ( 7 ) and sulfone ( 8 ) derivatives by NaIO4 and H2O2 30%/DEAD (diethyl azodicarboxylate), respectively, in high yields. In order to obtain structural information, sulfoxide 7g was characterized by X‐ray diffraction analysis. The preliminary bioassay indicated that the compounds 6a and 7g exhibit potential antitumor activity. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:543–548, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20059 |