.beta.-1-(5,6-Di-O-acetyl-3- phthalimido-2,3-dideoxy-D-ribo-hexofuranosyl)-5-chlorouracil 133488-36-5 2,4(1H,3H)-Pyrimidinedione, 5-chloro-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-002535 AIDS002535 DiOAcPhthN-D-ribo-ddU deriv.