5-Fluoro-1-(3,4,6-trideoxy-.beta.-L-glycero-hex-3-enopyranos -2-ulosyl) uracil 5-Fluoro-1-(6-methyl-3-oxo-3,6-dihydro-2H-pyran-2-yl)-2,4(1H,3H)-pyrimidinedione AIDS-134920 AIDS134920 NSC633971