.beta.-1-(5,6-Di-O-acetyl-2,3-dideoxy-3-phthalimido-D-ribo-hexafuranosyl)uracil 133488-30-9 4(1H,3H)-Pyrimidinedione, 1-[5,6-di-O-acetyl-2,3-dideoxy-3-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-.beta.-D-ribo-hexofuranosyl]- AIDS-002530 AIDS002530 DiOAcPhthN-D-ribo-ddU deriv.