6-methyl-1-(2',3'-O-isopropylidene-β-D-ribofuranosyl)pyrido<2,3-d>pyrimidine-2,4(1H,3H)-dione

1-(5-bromo-5-deoxy-2,3-O-isopropylidene-β-D-ribofuranosyl)-5-dimethylaminomethylenebarbituric acid

1-(5-chloro-5-deoxy-2,3-O-isopropylidene-β-D-ribofuranosyl)-5-dimethylaminomethylenebarbituric acid

6,5'-O-cyclouridin