1-((2R,3S,4R,5R)-3-Fluoro-4-hydroxy-5-methyl-tetrahydro-furan-2-yl)-2,4(1H,3H)-pyrimidinedione 1-(2,5-Dideoxy-2-fluoro-.beta.-D-arabinofuranosyl)uracil 105281-08-1 5'-deoxy-FAU AIDS-191191 AIDS191191