1-((2R,3S,4R,5S)-3-Fluoro-4-hydroxy-5-mercaptomethyl-tetrahydro-furan-2-yl)-5-methyl-2,4(1H,3H)-pyrimidinedione 1-(2,5-Dideoxy-2-fluoro-5-thio-.beta.-D-arabinofuranosyl)thymine 105281-19-4 5'-SH-FMAU AIDS-191193 AIDS191193